The Start: Department of Natural 
Philosophy & Astronomy, 1826-1865
LARDNER: 1827-1831
   Museum of Natural Philosophy
   The Lecture Courses
RITCHIE: 1832-1837
   Resumption of Teaching
   The Apparatus
   Ritchie's Researches
SYLVESTER: 1837-1841
POTTER: 1841-1843
BROOKE: 1843-1844
POTTER: 1844-1865
Department of Mathematical & Experimental
Physics, 1865-67
   CAREY FOSTER: 1865-7
   The Courses
Department of Physics: 1867
   Developments in Practical Physics
   Admission of Women Students
   Academic Assistants
   Development of Lecture Courses
   New Accommodation
   Old Students
   Carey Foster Obituary
   William Grant
CALLENDAR: 1898-1902
TROUTON: 1902-1914
BRAGG: 1915-23
PORTER: 1923-28
ANDRADE: 1928-50
      1914 war
      Back in College
   Quain Professor
      Viscosity of Liquids
      Physics of Metals
      Other researches
   Extra space for research
   The War Years, Bangor 1939-44
   Back in Gower Street
   At the Royal Institution and afterwards
   Andrade: concluded
   Outstanding members of Andrade's department
      Nicholas Eumorfopoulos
      Dudley Orson Wood
      Leonard Walden
MASSEY: 1950-75
      Hoddles Creek, 1908-20
      Queen's University of Belfast, 1933-38
      Mathematics Department, U.C.L., 1938-39
      The War Years, 1939-45
      Mathematics Department, 1945-50
   Quain Professor; Department of Physics:1950-72
   60th birthday
Department of Physics and Astronomy: 1972
   Departmental Resources
   Resources Survey of the Department
      High Energy Physics
      Astronomy and Space Research
      Image Processing
      General Comments on the Research Work
      Effective Staff-Numbers
      Quain Professor
   Survey of Research A: Experimental
      Gas Discharge Studies
      Optical Techniques
      Atomic Physics
      Atomic Physics Group
      Ionic and Electronic Physics Group
      High Energy Atomic Collisions Group
      The Microtron Group
      Double Magnetic Lens Spectrometer
      The Emulsion Group
      Cloud Chambers
      Nuclear Physics Group
      The Bubble Chamber Group
         Search for evidence of C-violation
         Track-sensitive target
      Spark Chamber/High Energy Physics
      Counter Group
      Space Science
         Mullard Space Science Laboratory
         Solar X-ray and Ultra-Violet Astronomy
         Cosmic X-ray and Ultra-Violet Astronomy
         Involvement in UV Satellites
      Space Science & Atmospheric
      Structure Group
      Ultra-violet and Optical Astronomy Group
         Satellite UV astronomy
         Balloon UV astronomy
         Optical astronomy (IPCS)
      The Observatory Group
         Stellar studies
         Planetary Geology
      Infra-red Astronomy Group
      Positron Physics Group
      Image Processing Group
      Molecular Beam Group
   Survey of Research B: Theoretical
      Atomic Physics & Astrophysics Group
      High Energy Physics Group
      General Physics Group
      CUSC (Computers in the Undergraduate Science Curriculum)
   Review of other Departmental Affairs
      Degree Courses
      Teaching Administration
      Professors' Meetings
      Academic Staff Meetings
      Staff-Student Consultative Committee
      Students' Societies
      Tea parties
      Cumberland Lodge Weekend
      Annual Cricket Match
      Institute of Education Courses
      Student Numbers
      Postgraduate Students
   Massey: concluding biographical memoirs
      Space Research (1953-78)
      Science Policy (1953-83)
      Royal Society
      Honours and Distinctions
   Scientific papers

The Observatory Group

After becoming Perren Professor in 1972, Wilson continued with research carried out in his previous position as Director of the SRC Astrophysics Research Unit, Culham, namely the means of heating the solar corona and some studies of plasma spectroscopy. He began studies of the current data arriving from the sky-survey telescope on TD-1, and he continued to be involved in the IUE project on the UK management side, firstly as a consultant in 1973, and then as director, nominally on a half-time basis, from May 1975.

Ultra-violet observations of g2 Velorum (WC8 + OPI) were made by the sky-survey telescope on TD-1 in 1972 and 1973 at different phases in the period and analysed by Wilson and Willis. The luminosity ratio of the two components showed that the O9I star was the brighter in the UV, as well as the visible, by between 1.4 and 1.8 mag. The spectrum of the WC8 component agreed well with the UV spectrum observed for a single WC8 star, HD 192 103. Considerable variations in the spectra of g2 Velorum were interpreted in terms of an eclipse of the O9I component by the stellar wind resulting from the expanding WC8 envelope. An estimate was made of the mass loss from the WC8 component, but its accuracy was severely limited by the uncertainty of the carbon abundance in the WR component.

Wilson & Boksenberg had collaborated with the Culham Laboratory in the second successful launching from Woomera on 16 June 1973 of a star-pointing Skylark rocket. The vehicle was equipped with a three-axis attitude stabilisation system and instrumentation for high resolution UV spectroscopy of g2 Velorum and z Puppis. The objective of the flight was to record the spectra with adequate spectral resolution to observe interstellar absorption lines and to study line profiles produced in the stellar atmosphere and the expanding circumstellar region. The instrumentation included three objective grating spectrographs giving three overlapping ranges to cover the wavelength band from 900 to 2300 Å. The linear dispersion was 0.12 mm/Å with a theoretical optimum spectral resolution of c. 0.3 Å. The first star was observed for 103 s and then a programmed change of vehicle attitude was made to acquire the second star, which was observed for 62 s, the period being terminated by loss of stabilisation when the altitude of the payload decreased below 120 km. The high-quality spectra obtained of both stars gave new information about their stellar atmospheres and the interstellar gas in the direction of the Gum Nebula.

Wilson and Willis studied the most extensive set of observations then available of the UV spectra of Wolf-Rayet stars; they were made by the sky-survey telescope on TD-1 and covered nine objects - three WC, three WN and three WC + O binaries. The observations, combined with ground-based observations, were analysed for both the continuum energy distributions and line strengths. The flux distributions, corrected for interstellar extinction, were compared with model atmosphere calculations to give colour temperatures, and Zanstra temperatures were computed from the intensity of the He II 1640 Å line resulting in some 30,000 K, somewhat lower than previously thought. The strengths of He, C and N lines in four WR stars (one WC and three WN) were analysed theoretically to obtain the abundances of these species, it being known that the H/He ratio was negligible in WR stars. In the WC star the C/He and N/He ratios lay close to the normal cosmic value whereas for the WN stars the N/He ratio was slightly higher, and the C/He ratio much lower than normal. Thus it appeared that the C abundance was the controlling factor in determing the spectral characteristics of the WN and WC sequences, and it was concluded that WR stars were in the helium-burning phase, the WN stars being less evolved than the WC.

Wilson with K. Nandy & G. I. Thompson of the Royal Observatory, Edinburgh, and C. Jamar & A. Monfils of the University of Liege, Institute of Astrophysics undertook a systematic study of UV interstellar extinction with the sky-survey telescope. Firstly c. 100 reddened stars located in the three directions of Cygnus, the galactic centre and the anticentre were studied to derive mean extinction curves, remarkably similar with a strong maximum at 2200 Å. The curves were derived from a comparison of reddened and unreddened stars of the same spectral type, although the accuracy was limited by the relatively restricted number of sufficiently unreddened stars suitable for comparison. This number was therefore increased in a second study of several hundred stars by the inclusion of slightly reddened stars to obtain a sufficient sample in each spectral type and luminosity class. The stars were divided into groups according to their galactic positions and a mean extinction curve derived for each galactic region situated in the local arm, the Carina-Sagittarius arm and the Persus arm. The curves did not show any significant differences so all the observations including UVB data were used to give a single mean curve in terms of total extinction for unit visual colour excess. The apparent constancy of the interstellar extinction law was confirmed by the same mean value per unit visual colour excess in each galactic region. However in the case of the colour excess E(2190-2500), which is linearly related to the 2200 Å feature, a few individual stars appeared to show anomalous behaviour.

Wilson & D. J. Carnochan with Nandy & Thompson studied the galactic distribution of the agents causing the extinction bump near 2200 Å and the UV colour excess E(1550-2740) within 2 kpc of the Sun in the galactic plane. The mean reddening - distance relation in the galactic plane was obtained for different longitudes. A study of the extinction parameter with galactic latitude showed a strong concentration of the dust towards the galactic plane with a scale height of 110 pc.

Using the sky-survey data, Willis and Wilson showed that the UV extinctions of the WR stars, WN6 HD 192163 and WC7 HD 156385, exhibited a pronounced excess in the 2200 Å absorption band. Although the former was surrounded by the nebulosity NGC 6888, no nebulosity associated with the latter was detected. Because of their similarity to WR stars, in sharing the characteristics of extended atmospheres and mass loss, the UV data for 23 Of stars were analysed, but no extinction anomalies were found.
The launch of IUE on 12 January 1978 opened up the study of astronomical objects from normal stars to quasars and clusters of galaxies enabling Wilson and his colleagues to gain an international reputation as one of the leading centres of cosmic ultra-violet astronomy. Wilson was elected FRS in 1975; awarded the CBE in 1978; succeeded Heymann as Head of Department in 1987; received the USA 1988 Presidential Award for Design Excellence on behalf of the British scientists involved in IUE; and was created a Knight Bachelor in 1989.

D. McNally having developed a spherically symmetric model of star formation, had relaxed that constraint in order to include the effects of rotation and magnetic fields. The problems were severe, but two methods of solving the equations appeared promising. Approximate studies suggested that previous ideas about the inhibition of star formation by rotation could be wrong, and questioned the entire problem of stellar instability produced by rotation. His study of the interstellar medium from which stars are formed also involved W. B. Somerville. It was based on the analysis of interstellar absorption lines in the spectra of distant stars observed with large telescopes, mainly the 74 inch Radcliffe telescope in S. Africa, and the 100 inch telescope at Mt. Wilson. The work benefited from observations in the ultra-violet and infra-red spectral regions by other groups in the department, and would be extended by use or the IUE.

W. B. Somerville was also developing theoretical models of stellar atmospheres for the analysis of observed stellar spectra to determine the temperature, density and chemistry of the atmosphere. In addition quantum mechanical calculations of atomic structure were being made (see p.132).

D. R. Fawell was analysing observed spectra on the basis of model atmospheres to determine the chemical composition of metallic-deficient and metallic-excess stars, the former being very old stars, whose composition is representative of a very early stage of the galaxy, and the latter having an anomalous chemistry not fully understood. Ultra-violet spectra from TD 1 were adding to those in the visible region.

J. E. Guest was involved in a geological study of the Moon and planets using pictures received from the American space programme in which he was accorded scientific investigator status. The Apollo mission led to studies of lunar volcanism and the mechanism of impact cratering. The flybys of Mercury by Mariner 10 on 29 March and 21 September 1974 led to a series of joint papers on the geologic/terrain map; tectonism and volcanism; and some comparisons of impact craters on Mercury and the Moon. The Viking project launching two unmanned spacecraft to Mars in 1975 led to another series on some Martian volcanic features; Martian impact craters and emplacement of ejecta by surface flow; geology of Chryse planitia; geological observations in the Cydonia region; geology of the Valles Marineris; and geologic map of the Casius quadrangle of Mars. The work indicating the importance of volcanism as a planetary process led to the study of the eruptive mechanisms on the volcano Etna as a complementary programme.

Infra-red Astronomy Group

As mentioned on p. 63, this group was started by Massey in 1966 to make observations in the far infra-red spectral region, the one in which very few astronomical observations were being made, by using a telescopic system carried on a plastic-film balloon to altitudes where the atmospheric absorption, particularly of water vapour, was negligible. Jennings, whose work on the microtrons had ended, became leader of the group, being joined by his associate, Aitken, who was to concentrate on ground-based observations, and Dr. T. A. Clark, a newcomer to the department, who had some experience in the use of high altitude balloons.

In 1965 interest in the use of balloon platforms for scientific observations had led to a National Balloon Programme to facilitate the work of the universities in this field. Having completed their work on the liquid bubble chamber, Tomlinson, Towlson and Venis of the Engineering Design Group, were free to undertake a design study for a balloon-borne stabilised platform for general use on which scientific equipment could be mounted. A tour of USA studying balloon payloads built there, convinced Tomlinson that no single platform could meet the diverse requirements of all balloon experiments. Hence the design study concentrated on stabilising a telescope to point accurately at selected stars. The proposed design did not materialise owing to financial restraints, but the experience gained was put to good use when in 1967 Tomlinson put forward a a design for a balloon-borne telescope system, tailored to the requirements of the infra-red group, which was able to be built in the departmental workshop. The platform of dimensions 1.7m x 1m and 2.3m height and loaded weight 340 kg carried a 40 cm, f/5.5, Cassegrain, Dall Kirkham, telescope, biaxially pointed and stabilised to ±1 min arc by a star sensor with a 2 deg field of view and + 5 guide star magnitude requirement. Acquisition of a selected star was programmed or commanded by reference to a magnetometer and the elevation angle, and for scanning the telescope was offset sequentially from the star tracker to cover an area of ± 5 deg arc from the guide star. A plane, Nasmyth, mirror reflected the beam through a hollow elevation shaft, where a gold-plated mirror reflected the infra-red radiation into the photometer while transmitting visible radiation to a photomultiplier tube. The photometer used a gallium-doped germanium bolometer, together with a quartz Fabry lens, filters, and an aperture stop, all cooled to 1.8 K in a liquid helium cryostat. The telescope, when built, was taken to Australia, where with the help of Professor Hopper's group at the RAAF Academy, Point Cook, Victoria, it was assembled and taken to Mildura for its first flight in July 1970. A second platform was constructed in the department for Boksenberg's ultra-violet astronomy studies.

Meanwhile, in order to test the suitability of observing sites, the group developed a simple, portable instrument for making observations of the water vapour content of the earth's atmosphere from the ground by comparing the intensity of solar radiation in and on the edge of water vapour bands at 0.94 or 1.87 m, both spectral bands in the operating region of lead sulphide detectors being selected by interference filters. Messrs. R. A. Hirst and J. Todd, visitors from the University of Melbourne, Australia were associated with Jennings in this work. A Michelson interferometer, of the type developed by Dr. H. A. Gebbie of NPL, was built and used by Jennings and A. F. M. Moorward with Fourier transform multiplex techniques and a vacuum thermocouple detector in a flight made from the National Centre for Atmospheric Research (NCAR) Balloon Flight Station, Palestine, Texas on 19 August 1969 to measure the thermal radiation from the atmosphere in the range 100-1000 cm-1 (10-100 m), with a mean resolution of 34 cm-1, as a function of height up to 38 km. The results showed that considerable emission was still present at aircraft altitudes and that radiation from the 15 m CO2 band was still received at 38 km. Only at altitudes above 30 km could the transmission in the 100-300 cm-1 (33-100 m) region be considered complete. Then in the following September measurements were made of the brightness temperature of the Sun in the range 65 to 180 cm-1 by Clark, Jennings and G. R. Courts during a balloon flight to a height of 32.6 km from NCAR using the Michelson interferometer with a Golay cell detector. A platform built for the SRC by the Hi-Altitude Instrument Co. Inc., Denver was used in this work.

Observations were made with the UCL telescope, using the 40-350 m waveband, the short wavelength 'cut-on' being determined by the quartz Fabry lens and a black polythene filter and the upper limit by diffraction effects. The system's relative response, having been determined by laboratory measurements in a vacuum tank using a Michelson interferometer, was made absolute by observing a suitable planet during flight. Progress was rapid, the group establishing a leading position in the field. At the Eighth ESLAB Symposium, held during 4-7 June 1974 in Frascati, Italy, on H II regions and the Galactic Centre, 40-350 m fluxes were presented for 56 sources, observed within the telescope's pointing accuracy to be coincident with thermal galactic radio sources of known G numbers. The infra-red and radio continuum data were used to investigate the relationship between infra-red and radio flux, and to estimate effective dust absorption depths and dust-to-gas ratios within the ionised regions.

Two flights of the UCL balloon-borne telescope took place from NCAR in September, 1971, the performance being satisfactory. Broad-band, 40-350 m, flux measurements were made for the far infra-red sources in the Orion Nebula (M42) and NGC 2024, and an upper limit was established for the far infra-red flux from the Crab Nebula (M1). These observations were made on the second flight, when Saturn was observed to determine the flux sensitivity of the system. Mars was observed for calibration purposes on the first flight, when four sources, not previously observed in the far infra-red, were detected. Of these, one appeared coincident with the continuum radio source, G133.7 + 1.2, in W3, classed as a compact H II region, another was identified with a dark nebula, Lynds 1962, but no identifications with known objects were found for the others.

There followed a series of flights from NCAR during September 1972 and April to May 1973 bringing the total of galactic sources observed up to 56. In the former series, based on observations of Jupiter for absolute calibration, large 40-350 m fluxes were measured from a variety of H II regions, the far-infrared luminosities being mostly in the range 1 - 20 x 105L‰. Each source was observed several times, and contour maps of the two extended regions, NGC 6357 and NGC 6334, were constructed from a series of close scans. The sources DR 15, G351.6 + 0.2, RCW 117 and IC 4628 had not been observed before in the infra-red, and G334.4 - 0.4, together with the three components in NGC 6334 were new identifications. Three objects, namely KE 52, RCW 122 and RCW 117, lying on the edge of the Sagittarius arm, in a region where considerable star formation was taking place, were found to have luminosities greater than 106 L‰, and surprisingly high luminosities were found for DR 15 and G351.6 + 0.2. A scan of the reported position of HFE 28 failed to reveal any object of the required intensity to support its correspondence to G353 - 0.4, a compact H II region, associated with a class I OH source. The discovery of IC 4628, based on only one scan, required confirmation. The infra-red maps of NGC 6357 and NGC 6334 showed similar structure to that observed at radio-continuum frequencies. In the former case the two infra-red components corresponded to the two compact H II regions, the brighter infra-red component being associated with the weaker of the two radio sources.

However, in the case of NGC 6334 the brightest infra-red source did not coincide with a compact H II region, but was associated with an OH/H2O maser source.

During the Spring 1973 flights, there were obtained a map of the W3 region and broad-band fluxes of RCW 36, RCW 38, W 49 and 24 objects mostly in H II regions lying along the galactic plane between longitudes 327 deg and 349 deg, the named objects being specifically searched for, and the rest identified later from raster scans in complex regions such as Norma. Three distinct 40-350 m emission regions were observed in W3, agreeing in position, to within 1', with the centres of the radio components on a 2 cm map, but the main continuum component, coinciding with the optically visible nebula IC 1795, showed a new feature, namely a pronounced extension. W3(OH), a weaker continuum source, but the strongest centre of OH emission in the region and containing an H2O maser, had a far infra-red flux 3.3 times greater than the 2 cm flux for W3 (continuum). The third source, W3(N), not previously measured in the infra-red, had a ratio of far infra-red to 2 cm flux only about half that of W3 (continuum). Three sources were detected in the region containing the optically identified and extended nebulosities, RCW 38 and RCW 36. W49 having a far infra-red luminosity of 22.5 x 106 L‰, appeared to be the most luminous far infra-red source outside the galactic central region. Seventeen sources all lying along 11 deg of the galactic plane in the direction of the constellation Norma and six along the galactic plane in the direction of the Scorpius constellation were observed. The Norma group included one source, identified with the optical nebula, RCW 99; two corresponding to thermal peaks associated with the optically identified nebula, RCW 106; and G333.6-0.2, one of the brightest radio sources, whose radio flux and far infra-red luminosity, of 2 x 106 L‰, implied the presence of of more than one early-type star in the region. The 8-13 m spectrum, measured by Aitken and Jones, clearly showed the 12.8 m line of Ne II, but was otherwise featureless; they considered the emission to arise from optically thin dust containing silicates, with extinction in a cold dust envelope cancelling the silicate emission feature (see p. 112). The Scorpius group included RCW 120 and two sources apparently associated with the single radio peak, G347 - 0.2.

Maps were also obtained of W51, a highly obscured region consisting of a number of compact H II sources, and also of the Galactic Centre region in the 40-350 m band. A low resolution spectrum (32 cm-1 apodised) was obtained of the main component of W51, namely G 49.5 - 0.4, using a Michelson interferometer, following one of Saturn. Two raster scans of the W51 region were made, the first having 15 individual scans and the second 18, the scanning direction being approximately along the the line of the sources. Comparison of the final map with a radio map at 15 GHz showed that in general there was very close agreement between the infra-red and radio contours. The radio and infra-red positions of the four main components agreed to within 2', except in the case of G 48.9-0.3, which was unresolved from the small radio source, G 49.0-0.3, on the infra-red map. The peak infra-red fluxes of the four components G 49.5 - 0.4, G 49.4 - 0.3, G 49.2 - 0.4 and G 48.9 - 0.3 were 60, 19.5, 12.5 and 14.0 x 10-10 W/m2 respectively.

G 49.5 - 0.4, was known to consist of at least eight separate radio sources, the four strongest lying within a circle of radius c. 11/2' and accounting for over 85% of the radio flux. The infra-red spectrum was based on a simple spherical model of the complex source, various measurements up to 1000 cm-1 being used, including the series between 100 and 250 cm-1 obtained by the Michelson interferometer during the flights. The agreement of the latter with a 100 K curve normalised from the photometric measurements was reasonably good, but the points did not lie on a smooth curve. It was found that for a grain temperature of 48 K both water ice and silicates gave reasonable fits to the data, with water ice showing fluctuations between 100 and 200 cm-1 similar to those observed, but somewhat displaced, possibly due to impurities.

50 individual scans were made of the Galactic Centre region, the resultant map showing reproduction in the far infra-red of many of the radio features of a 5 GHz map. As well as the main components, Sgr A, Sgr B2, Sgr C and Sgr D, there was a marked similarity between the contours to the north of Sgr A and the two radio sources to the south of Sgr C. The six sources of infra-red emission observed by Messrs. Hoffmann, Frederick & Emery (HFE) in their 100 m survey were confirmed except for the most southerly source, Sgr E in their paper, which was not seen. Separated fluxes, sizes and integrated luminosities were obtained for the main components, Sgr A, Sgr B2 and Sgr C, the separated luminosities of 36.5, 13.0 and 12.0 x 106 L‰ respectively, being approximately half the values reported by HFE for a smaller spectral band, 75-125 m. This was not necessarily inconsistent since the fluxes had been separated from the 'intensity ridge' which runs from Sgr B2 to Sgr C and were considerably smaller than the HFE ones.

Members of the group involved with Jennings in the foregoing observations and analysis of the data were Messrs. J. A. Alvarez, J. P. Emerson, I. Furniss, K. J. King and A. F. M. Moorwood; W. A. Towlson, with R. W. Catch, R. Want and A. H. Watts, prepared the system for flights and provided valuable assistance during the flights.

The construction at UCL of a Mk II balloon telescope having a larger aperture, 60 cm, and better stabilization, some 4" r.m.s., than its predecessor, led to a programme of astronomical spectroscopy at 0.05 cm-1 resolution between 100 and 250 cm-1, using a Michelson interferometer, designed primarily for measurements of fine structure emission lines from H II regions. The first flight of the system took place at NCAR in October 1976, when only atmospheric results were obtained owing to an early power failure on the telescope system, and unfortunately a free-fall destroyed the gondola. After rebuilding the system was launched on a successful series of flights, starting in the Spring of 1978, when observations were made of O III, O I, and N III fine-structure lines in H II regions, this being the first time that both [O III] lines had been measured simultaneously. Observations continued to concentrate on the measurement of far infra-red fine structure lines in different regions, including the Orion Nebula and M17. They gradually came to an end as interest turned to satellite observations, in particular, on the Infra-red Astronomical Satellite, a joint effort effort by the USA, Holland and the UK, which operated continuously from January to November 1983.

As mentioned earlier, the group soon became involved in the use of ground-based instruments for observations through the so-called atmospheric windows where the attenuation is relatively small, Aitken taking a leading part in this side of the work. Working at the Mill Hill Observatory with the 24-inch reflector, firstly a Golay cell was used with a preliminary chopping and phase sensitive detection system. Then a more refined chopping system was developed for use with a gallium-doped germanium bolometer, cooled to 1.8 K by liquid helium. This was used with P. G. Polden to measure the 10 m flux from the Crab Nebula on four nights in January and February, 1971, the effective diameter of the telescope being reduced to 18 inch to optimize performance of the bolometer. The results of the observations indicated a flux of 170 ± 50 f.u. at 10 m, greatly in excess of 30 f.u., the expected value from the usual synchrotron model, the most likely explanation of the excess being thermal emission from graphite grains.

Instead of using variable interference filters for spectral observations, Aitken substituted a diffraction grating to attain higher and more consistent resolution. With Barbara Jones the 8 to 13 m spectrum of Jupiter was observed with resolution (fractional increment of wavelength) of 0.007 on two successive nights in May 1972 using the 60-inch Tenerife infra-red telescope, probably the first observations made with the telescope since it had become operational only a few weeks earlier. The spectrophotometer consisted of a grating mounted in a modified Czerny-Turner configuration and driven by a stepping motor, the radiation being detected by a gallium-doped germanium bolometer at 1.8 K. Resolution was defined by an aperture in front of a KBr Fabry lens forming an image on the bolometer. The aperture, lens and filters defining the 10 m region were in thermal contact with the base of the cryostat at 1.8 K.

The grating spectrometer and germanium bolometer were used by Aitken and Jones on the 98-inch Issac Newton Telescope at Herstmonceux in November 1972 to make observations of NGC 7027 from 10 - 12 m with resolution 0.005 and a beam size large enough to include the greater part of the H II region; they were undertaken to obtain further data on the S IV line at 10.5 m and the 11.3 m feature seen by Messrs. Gillet, Forrest & Merrill (GFM) when observing NGC 7027 between 8 and 13 m using a narrow band interference filter with resolution 0.015. The S IV line was clearly seen, as was the GFM feature, maybe resulting from thermal emission by MgCO3 grains, and a previously unobserved sharp feature was detected at 11.9 m. A sulphur abundance between 6.86 and 7.12, relative to H = 12.00, was deduced from the intensity of the S IV line, and the possibility that the 11.3 and/or 11.9 m features were due to unresolved clusters of lines was considered. Further observations with the INT were made on 29 November 1972, namely medium-resolution spectra in the 8 to 13 m range of the infra-red source IRS 5 discovered earlier in the month by Messrs. Wynn-Williams, Becklin and Neugebauer during detailed mapping at 20 m of part of the compact H II region, W3. It appeared that IRS 5 was a luminous object suffering a large extinction by an extended dust cloud and that the cool source in W3, which had been observed at 100 m, was probably associated with this obscuring cloud. When compared with similar spectra of the Becklin-Neugebauer (BN) object in Orion and the galactic centre, IRS 5 appeared to be an extremely compact dust cloud, optically thick at 10 m and of high luminosity, probably containing a massive protostar. The 10 m emission from the galactic centre and the BN object could be thermal radiation from optically thin dust of the same composition as that obscuring all these scources. J. M. Penman joined Aitken and Jones in observations of ionized neon in the galactic centre, made with the grating spectrometer mounted on the 60-inch telescope at Izana, Tenerife, during May 1974 and then in September 1974, February and May 1975. In the first observations of the 12.8 m Ne II fine structure line from Sgr A (West) the thermal nature of the source was confirmed, the neon abundance in the region appearing approximately normal, and the gas to dust ratio very large. In the more extensive study, a search for Ne II line emission was made in a number of nearby regions. The line was found to peak at 12.81 ± 0.005 m, the source being established as a thermal H II region of low excitation with a near normal abundance of at least one heavy element. No northerly extension of the emission was found, as suggested by radio synthesis maps. Aitken, J. Griffiths and Jones investigated the effect of heavy element abundances in stellar atmospheres on the ionization structure of the galactic centre. They concluded that observations of ionized neon were most readily fitted on the basis of heavy elements being overabundant by a factor of three compared with solar values, and ionization provided by stars with effective temperatures around 40,000 K.

Spectral observations of G333.6 - 0.2, the compact and very bright radio and infra-red source, were made by Aitken and Jones with the Ratcliffe 74-inch telescope at Pretoria during two nights in July 1973, the wavelength range 8-13 m being explored in equal intervals of 0.021 m with resolution 0.005. The fine-structure Ne II line at 12.80 m was detected and a neon abundance in the range 7.63-7.93 found in agreement with estimates of the cosmic value. The continuum radiation was considered to be thermal emission from optically thin dust with extinction in a thicker cold dust envelope, both distributions containing silicates, and the optical depth of the dust in emission being consistent with the observed ratio of infra-red to Ly alpha excess. They were joined by Griffiths in the further observations of the source made in July 1975, the spectrometer/ photometer being mounted at the Cassegrain focus of the 150-inch Anglo-Australian telescope on Siding Spring Mountain. High resolution maps of the source were obtained in the Ne II line and infra-red continuum emission at 12.5 m, the remarkably similar distributions showing a simple, compact and nearly symmetric source. The spatial observations and the radio continuum properties of the source were explicable in terms of a simple distribution of density surrounding the ionizing source, the similarity between the neon line and infra-red continuum spatial distributions providing independent evidence for a region severely depleted of dust, especially in the compact core, compared with the interstellar medium.

Aitken and Jones mapped the nova-like, h Carinae at 12 and 20 m with a resolution limited by diffraction of the 74-inch Radcliffe during July 1972 and 1973. The results of this mapping, together with 10 m spectra of the inner and outer regions and a 20 m spectrum, showed a remarkable similarity to the visible spatial distribution and provided evidence for more complex infra-red structure, and indicated an optically thin inner region surrounded by cooler thicker dust. They were joined by Messrs. J. D. Bregman, D. F. Lester and D. M. Rank of the Lick Observatory, University of California, in making further observations of the nebula on the nights of 9-13 July 1976. The 4 m spectral observations were made with the Anglo-Australian telescope, the measurements being taken by the more sensitive, liquid helium-cooled, grating spectrometer with an array of 24 Hg:Ge detectors. The Brackett-alpha line of hydrogen and the adjacent continuum were observed at several positions along an E-W line through the centre of the nebula extending to the edge of the outer shell, the greater part of the line and continuum radiation arising in a small central source, slightly narrower in the line radiation. In the spatial and spectral studies of an ionization front region in the Orion nebula using the Mauna Kea Observatory 2.2 m and the Cabezon 1.5 m telescopes, the array of 24 Hg:Ge detectors were replaced by an array of 5 As:Si photoconductors, the central three, sampling adjacent spectral elements with a resolution of 0.045 m, and the outer two having a resolution of 0.015 m and separated in wavelength by 0.85 m. This type of photoconductor continued to be used with various telescopes including the 3.8 m UK Infra-red telescope in Hawaii, a notable instance being the use of between 3 and 30 photoconductors involved in the 8-13 m spectrophotometric study of 24 compact planetary nebulae and other emission line objects, resulting in 19 being published for the first time.

After becoming a Reader in the 1979-80 Session, Aitken left UCL at the end of the 1981-82 Session to join the Department of Physics at the University of Melbourne.

Positron Physics Group

This was another group started in 1968 at the suggestion of Massey. His interest in positrons stretched back to the theoretical prediction of their existence by the work of Dirac and Oppenheimer. In 1952 his old friend and collaborator in theoretical atomic physics, C. B. O. Mohr of Melbourne University, spent his sabbatical year in Massey's room and they made a preliminary survey of the collision processes of positrons and positronium in gases. With A. H. A. Moussa, a research student from Eygpt, Massey considered positronium formation in helium, and D. A. Fraser spending some time in the department, undertook calculations concerning positromium collisions in hydrogen and helium. Meanwhile Massey was anxious to develop an experimental research programme on positrons in gases. He persuaded Heymann and Duff, who were actively involved in experimental particle physics, to take on a new research student, J. J. Veit, to work on the quenching of positronium. Although some good measurements were made of quenching rates, the plan that new research students in high energy physics should gain experience with some positron experiments never materialised. However with the completion of the experimental research programme using the 50 MeV proton linac at Harwell to measure polarization parameters in double and triple scattering of nucleons by protons, Massey suggested to T. C. Griffith that he should switch to experimental work with slow positrons. The availability of radioactive positron sources enabling work to be carried out in the department being an added advantage, Griffith not only agreed, but persuaded Heyland, an electronics expert, who was in charge of the third-year undergraduate laboratory, to join them. Massey suggested that the aim should be directed towards obtaining information about cross-sections for positron excitation of molecular vibration and rotation by accurate measurement of decay time spectra for pure molecular gases and for mixtures with other gases - a future programme as it turned out. In 1970 L. O. Roellig spent a sabbatical year with the group and in the following year K. F. Canter, who had worked with Roellig on positron annihilation in helium at low temperatures, joined the group enabling it to make a good start.

The work of the group developed along two lines running in parallel, one leading to the determination of total cross-sections for positrons in gases and the other to the measurement of lifetime spectra of positrons in gases. In the former, the group pioneered the use of MgO powder to produce positrons of energy c. 1 eV and, in the latter, it increased the rate of accumulation of data by at least an order of magnitude in comparison with the standard method, and formulated an exact method of evaluating and removing the background due to random events leading to the derivation of the true lifetime spectra from the raw data. It soon became one of the leading groups in the field of experimental, low energy, positron physics

The development of positron beam technology advanced dramatically with the discovery and design of efficient moderators to produce low-energy positrons. A striking discovery was announced by Groce et al in 1969 when moderating positrons to low energies, namely, that the number of positrons per unit energy interval in a band of energies around 1 eV was several orders of magnitude greater than expected. Coleman, Griffith and Heyland using a sodium 22 source and a moderator involving the 'backscattering' of fast positrons from a gold-lined cylinder found a yield of one slow positron per one million fast positrons, a factor of ten better than that observed by Groce et al. Canter joined them in the use of the same apparatus when a further factor of ten improvement was achieved by allowing fine MgO powder to settle on the gold lining of the cylinder. Further improvement of moderator design was achieved by replacement of the cylinder with gold vanes coated with a layer of MgO powder, and then it was shown that the yield was not greatly reduced if the powder was deposited on a fine grid provided it did not block the holes between the wires.

Applying the time of flight method to deduce the positron energy, Coleman et al initiated the timing sequence by detection of each positron as it traversed a thin plastic scintillator at the start of the flight path and ended it with a single NaI well counter at the target end of the path. The positrons from the scintillator entered the flight tube through a thin Melinex window aluminised on the surface in contact with the scintillator. The flight tube had a straight section of length 70 cm, diameter 5 cm, followed by a 15 cm section, curved in an arc of 25 cm radius; it could be maintained at a vacuum pressure of c. 10-6 Torr. An axial magnetic field confined the positrons to a helical path close to the axis all the way to the target. The last 2 cm of the tube was inserted into the well of the NaI counter and ended in an insulated Al foil target, biassed at a negative potential of 90 V to attract the positrons and ensure their annihilation in the target. The moderator used to produce the slow positrons was a short narrow copper cylinder, inlaid with gold foil, surrounding the axis of the flight tube at the radioactive source. The corresponding yield of low-energy positrons was one per million disintegrations of the Na 22 source or about 500 timed positrons per hour. The yield was substantially less for materials of lower Z than gold, e.g., copper, aluminium and polythene. A ten-fold increased yield was achieved when the gold surface was covered with a thin layer of fine MgO powder, obtained by holding the open end of the cylinder above burning magnesium, the energy of the positrons being 1.0 ± 0.5 eV. Further improvement in moderator design was achieved by replacing the tube with gold vanes, coated with a thin layer of MgO powder and inclined at 45 deg to the axis of the flight tube, a system similar to one stage of a venetian blind electron multiplier. The slow positrons from this moderator were produced almost in a plane normal to the axis and consequently suffered less time spread than those produced over the inner surface of the tube.

The time of flight of the positrons was measured by arranging for the light pulses from the detectors to be transformed into fast logic start and stop pulses, fed to a time-to-amplitude convertor, whose output was fed to a multichannel analyser where the time of flight was stored and displayed; it was also necessary to count the total number of of start and stop pulses accurately and, where necessary, allow for any loss of counts due to dead time effects. Fast counting electronics were essential, the high counting rates of c. 1.5 x 106 counts/sec in the source counter presenting some special problems; this limited the source strength to c. 100 mCi. Slow positrons in the 1 eV peak were detected at a sufficiently high rate (c. 1-3/s) to enable the determination of accurate cross-section measurements.

Canter, Coleman, Griffith and Heyland made total cross-section measurements for positron-helium collisions in the energy range 2-20 eV using the gold-vanes moderator, the attenuation of the positrons being measured when high purity helium was continuously leaked into the flight tube. A preliminary value of the 8 eV cross-section for krypton was also obtained. Then they made the first measurements above 20 eV by extending the energy range to 400 eV in helium, neon, argon and krypton. The helium cross-sections were also determined by the static method in which alternate runs of duration 200 s were taken, firstly with the flight tube evacuated and then filled to the appropriate pressure; the results were the same as for the dynamic method. The attenuation was measured at several gas pressures and the cross-section was deduced from a logarithmic plot of the total number of positrons in the peak, which had a FWHM of 1 eV, as a function of gas density; no departure from exponentiality was observed in any of the measurements. Using the same apparatus and method over the same energy range as for the inert gases, Coleman, Griffith and Heyland investigated H2, D2, N2, O2, CO and CO2.

With no forward scattering the time of flight spectra have the same shape for both vacuum and gas runs, the latter having reduced intensity. The cross-section may then be deduced from the ratio of the integral of the number of counts under the peaks for the two runs. With significant forward scattering the peak for the gas run is changed in shape, there being a tail on the low energy side of the peak, and the attenuation value at each channel in the peaks varies. Spectra for positrons in helium at 3, 30 and 300 eV showed that the ratio of counting rates per channel with and without gas was constant across the 3 and 30 eV peaks, implying no distortion, but it varied continuously across the 300 eV peak and only approached a constant value near channel 1 at the leading edge of the peak, where the contribution from scattered positrons tends to zero. The true attenuation, A, was therefore taken as the asymptotic value at the leading edge of the peak and the total cross-section was given by ln A /I, where I is the integral of the number density of gas atoms over the length of the flight path. This procedure was therefore introduced to make allowance for small angle scattering and for inelastic scattering involving small energy losses.

A plot of total cross-section against positron energy for all the inert gases illustrated a general pattern of increasing cross-section with energy, a relatively rapid rise occurring at the positronium threshold, to a maximum, the cross-section at a given energy increasing with atomic number. The rapid rise was most pronounced in the case of helium, the threshold being 17.8 eV and the maximum around 50 eV. In all cases the decrease of cross-section with decreasing energy at the lowest observable energy raised the possibility that a Ramsauer-Townsend minimum, such as occurs for electrons in argon, krypton and xenon, occurs at still lower energies. Theoretical analysis of the He results at energies below the positronium threshold, where only elastic scattering occurs, was carried out by J. W. Humberston and R. I. Campeanu. The variation of the elastic cross-section with positron wave number was in excellent agreement over the range corresponding to energies 2 to 20 eV.

The cross-sections in H2 and D2 were approximately the same at all energies, showing a rapid rise around 9 eV. Later results for hydrogen showed a distinct minimum between 2 and 4 eV followed by a gradual and then a rapid rise, starting at an energy near 8.63 eV, the positronium threshold; the rise in cross-section between 4 and 8.8 eV was assigned to elastic scattering, rotational and vibrational excitations since the break-up of H2 is very small between the dissociation energy, 4.48 eV, and 8.8 eV. In the heavier gases the cross-sections were much larger than those for H2 and D2. In N2, O2 and CO there was a gradual increase from 2 eV to a maximum around 20 to 25 eV, followed by gradual decrease to higher energies. In CO2 there was a sharp increase in cross-section close to the ionization threshold of 14.4 eV.

In the earlier experiments the correction for forward scattering did not fully compensate for the scattering which occurred near the target end of the flight path. A significant improvement in experimental technique was therefore made by the introduction of a gas cell into the flight path of the positrons to restrict the scattering close to the positron source. The cell of length 8 cm was mounted in a 20 cm diameter chamber inserted into the 90 cm flight path directly after the source assembly. Positrons entered and left the cell through small cylindrical apertures, from which the gas leaked out and was pumped away by a 4" diffusion pump beneath the scattering chamber. A 2" diffusion pump maintained constant conditions in the moderator region for vacuum and gas runs. A pressure differential of c. 50:1 between the cell and the main flight path resulted in some 80% of the scattering taking place in the localised region. Localisation of the scattering minimised the error due to failure of detection of small-angle-forward scattering and eliminated the spread of transit times arising from positrons scattered with uniform probability at all points on the flight path between moderator and detector. A series of time of flight spectra, obtained with this system for positrons in helium in the energy range 50 - 170 eV by Coleman, Griffith, Heyland & T. L. Killeen, exhibited the characteristic secondary peak corresponding to inelastically scattered positrons, not observed in the earlier experiments. A typical time of flight spectrum for 61 eV positrons in helium showed a secondary peak corresponding to positrons of energy 31 ± 1 eV, which had undergone inelastic scattering through small angles. Preliminary values for the total inelastic cross-section were deduced, namely 0.6 to 0.45 p ao2 for positrons with energies between 50 and 170 eV.

In an improved system, the scattering chamber had two stages of differential pumping arranged symmetrically on either side of the 8 cm gas cell, most of the gas therefrom being removed by a 4" diffusion pump mounted below, the remainder being removed by 2" diffusion pumps, one on either side of the cell; another 2" pump, 10 cm from the target end of the flight path, ensured that a minimum of target gas remained in that region under gas-flow conditions. Measurements of pressure at various points during gas-flow conditions indicated that c. 96% of the scattering occurred in the gas cell, the pressures in the moderator region and flight path being < 10-5 Torr. Thus constant conditions were maintained in the moderator region both for vacuum and gas runs. Using a 150 mCi Na 22 source and a moderator consisting of two overlapping tungsten grids coated with fine MgO powder, Griffith, Heyland, K. S. Lines and T. R. Twomey remeasured the total cross-section for positrons of energy 20-1000 eV scattering in helium, neon and argon. In order to study inelastic positron-helium collisions in detail, vacuum and gas runs lasting over several hours were taken. The peak due to inelastic scattering was clearly separated from the unscattered peak at energies between 50 and 300 eV, but outside this energy range the separation was not so clearly defined. The same general features were exhibited by neon and argon, although the separation between the scattered and unscattered peaks was less since inelastic scattering forms a smaller fraction of the total cross-section. The total cross-sections for helium and neon agreed with recent results of Brenton et al, but those for argon were significantly lower; in all cases they were consistently higher than the results of Coleman et al. The helium and neon data agreed with the sum rule predictions of Bransden et al. Replacing the NaI well counter by a channel electron multiplier to detect the positrons, the same team investigated the inelastic scattering of positrons by helium at intermediate energies. A much higher signal to background ratio, namely 20:1, was obtained with the modified detector, up to 7 timed positrons per second being detected in favourable conditions. The measured time of flight spectra, based on runs of duration up to c. 200,000s were analysed and a partition of the cross-sections amongst the various inelastic channels at energies between 20 and 500 eV were attempted. M Charlton and G. L. Wright joined Griffith and Heyland in using the system to measure the total scattering cross-sections for positrons in the energy range 15-600 eV in H2, O2, N2, CO2 and CH4. The modified measurement techniques and improved methods of correcting for forward scattering yielded results of higher absolute accuracy than the earlier measurements of Coleman et al. The new values of the cross-sections were higher than the earlier ones at all energies, confirming that the latter were not fully corrected for forward scattering.

The lifetime spectrum of positrons and positronium in a gas consists of the 'prompt' peak, due to the decay of para-positronium and positrons annihilating in the walls of the gas chamber and in the source; the shoulder region which persists while the positrons are slowing down due to collisions with gas atoms until they reach thermal equilibrium; and a composite region consisting of two overlapping exponential decay curves, one due to the thermalised positrons and the other to ortho-positronium. The decay constants for free positron and ortho-positronium annihilations are given by:

lf = wrZeff ; lp = olp + 4 r 1Zeff

where r is the gas density in amagats; wr is the Dirac rate for a free electron gas; olp the vacuum decay rate of ortho-positronium; and Zeff and 1Zeff are measures of the corresponding effective numbers of annihilating electrons per atom. Another important parameter is the fraction F of positrons forming positronium and this is deduced from the amplitudes of the aforementioned decay curves. This can be compared with values based on the Ore model, namely that positronium will only be produced permanently by positrons with energies in the comparatively small range, the so-called Ore gap,

Eex > E > Ei - Eps

where Eex is the threshold energy for excitation of the atom, which is not much less than its ionization energy, and Eps is the binding energy, 6.8 eV, of the ground state of positronium.

At the start of their work on the lifetime of positrons and positronium in gases, Coleman, Griffith and Heyland used a thin plastic scintillator for direct detection of the positrons from the Na 22 source. This method of defining the 'start' pulse gave high counting rates with a weak source since some 30% of the positrons from the source entered the gas and were detected instead of the much less efficient detection of the prompt 1.28 MeV g rays in the standard method. The 'stop' pulse was defined by one of the g rays from annihilation of the associated positron, both g rays being detected in a fast plastic scintillator. The rate of accumulation of data was an order of magnitude greater than in previous work, more than 107 events due to annihilation being recorded in a 24 hr period. Lifetime data were obtained with this system for argon, krypton and nitrogen. Coleman and Griffith also made a determination of the vacuum lifetime of ortho-positronium using Freon gas. However difficulties were experienced in ensuring a clean system owing to plastic therein, and the thin aluminium through which the positrons entered the vessel limited the gas density up to c. 15 amagats.

Coleman, Griffith, Heyland and Killeen developed a conventional lifetime system to exploit the exact signal restoration method for the data analysis. A small cylindrical pressure vessel, length 7 cm, diameter 3 cm, was machined from a drawn copper rod and had its inner surface electroplated with gold. A 5 mCi source of Na 22 was deposited on a gold spatula, mounted close to the wall of the vessel. The backscattering of positrons from the gold enhanced the proportion of positrons annihilating in the gas. The source was viewed by two 11.2 cm diameter x 7.5 cm fast plastic scintillators, mounted on photomultipliers. One scintillator was positioned behind the source to maximise the solid angle for detection of the prompt 1.28 MeV g ray, emitted within 3 x 10-12 sec of each positron, which initiated the 'start' pulse of the timing sequence, the other being on the opposite side of the vessel to detect one of the 0.5 MeV annihilation g rays for the 'stop' pulse. 'Stop' pulses due to the 1.28 MeV g rays accounted for less than 20% of the background events; the rates for the 'start' and 'stop' pulses were c. 104 and 2 x 104 sec-1 corresponding to detection efficiencies of 6% and 12% respectively; the delayed coincidence rate was 103 sec-1; depending on gas density up to 65% of the events were due to positrons annihilating in the gas; and the overall time resolution was better than 1.4 ns FWHM.

Lifetime parameters were determined for the inert gases, He, Ne, Ar, Kr and Xe, over various density ranges. As an example of the measurements at 297 K, the following values are reproduced for He over the density range, 2-60 amagat: Zeff = 3.94 ± 0.02; 1Zeff = 0.125 ± 0,002; the shoulder width = 1700 ± 50 ns amagat; and F = 0.23. Compared with theory the calculated value of 3.88 for Zeff at room temperature agreed well with the measured value and the shoulder region was well reproduced by the calculated phase shifts. The results included the first measurement of the shoulder width for Ne, namely 1700 ± 200 ns amagat. The measurements of F were consistent with the extreme predictions of the Ore model, as were those for neon and argon but those for krypton and xenon were far too low. The positronium formation fractions taken in conjunction with the positron beam total cross-sections enabled estimates to be made for the values of positronium formation and positron excitation cross-sections for helium and, with reduced accuracy, for neon and argon in the energy range from the positronium threshold Eo to the ionization potential Ei. These cross-sections were found to be c. 0.2 pao2 at Ei for helium and somewhat larger for neon and argon.

Measurements of the lifetime parameters for the molecular gases were also made for D2, H2, N2, CO, CO2, O2 and CCl2F2. The shoulder region in N2, the only molecular gas to exhibit this feature, was clearly established at 0.3 amagats. 1Zeff was found to be constant over a wide density range for N2. CO, CO2, H2 and D2, whereas for O2 it was large and decreased from 80 at 7 amagats to 14 at 200 amagats. Zeff decreased with density for N2, CO, H2, D2 and O2 whereas for CO2 it increased from 60 at low density to 120 at 50 amagats and for CCl2F2 from 750 to 1500 over the density range 0.3 to 5 amagats. F for N2, CO, CO2 and O2 increased with density, a notable feature in N2 being the increase from 0.19 near zero density to a maximum at 0.40 near 140 amagats followed by a gradual to 0.36 at 234 amagats.

All of the lifetime parameters are affected to some degree by the level of impurities in the gases under investigation, F and the shoulder widths being sensitive to small amounts of impurities. It was shown that as little as 50 ppm impurity in commercial grade helium increased F from 0.23 to 0.35, shortened the shoulder width by about 10%, but hardly affected Zeff and 1Zeff . Measurements of F in krypton-helium gas mixtures gave a maximum value of 0.46 at a concentration of c. 0.1% of krypton in the mixture, this value exceeding the sum of the fractions for low densities for the pure components. Measurements were also made for argon-helium mixtures, the slope So of the graph of F against argon concentration at zero concentration determining the probability of positronium formation in positron-argon collisions and thus being a measure of the positronium formation cross-section for argon. Later Charlton, Griffith, Heyland and Lines derived the formulae for determining the cross-section from Ssub>o; determined the enhancements of F for small quantities of Ne, Ar, Kr, Xe, H2, N2, O2, CO, CO2, CCl2F2 and C4H10 in He; and obtained the corresponding cross-sections from the experimental values of So. Wright joined in the measurement of the energy dependence of the positronium formation cross-section for the gases He, Ar, H2 and CH4 by passing a beam of slow positrons through a scattering chamber and detecting the positronium formed by counting the triple coincidences from the 3g decay of ortho-positronium. This was the first direct determination of relative positronium formation cross-sections using the beam technique; it clearly revealed the energy dependence of the O-Ps formation cross-section and showed that positronium formation occurs mainly in the energy region between Eps and Ei.

The decay rate of ortho-positronium was determined by Griffith, Heyland, Lines and Twomey as a function of gas density, the vacuum decay rate being deduced by extrapolation to zero density. Two conventional lifetime systems with sources of strengths, 1 and 2 mCi, respectively giving different signal-to-background ratios were used to check the signal restoration and analysis procedures. Two determinations were made with Freon-ammonia-helium mixtures, proportions c. 42, 42, 16%, respectively, two with iso-butane, one with n-butane and one with pure Freon-12 for comparison with the earlier data of Coleman and Griffith. The decay of the free positron component is so rapid for ammonia that the restored signal, after subtraction of the background, could be fitted to a single exponential term even for the lowest gas densities used. The most accurate results were obtained using iso-butane; n-butane had a smaller useful density range. The restored signal for Freon had to be fitted to the sum of two exponentials below 1 amagat with consequent loss of accuracy. The final value obtained for olp was (7.045 ± 0.006)/ms, which agreed with the existing theoretical value.

The Group continued to flourish, Griffith being appointed Professor in the 1980-81 session; it continued to attract first-rate postgraduate students, one of whom, Michael Charlton, who had made the first measurements of the cross-section for positronium formation in gases, later succeeded Griffith as Head of the Group.

Image Processing Group

The leader of this Group, Dr. M. J. B. Duff, was a research student in the Department of Physics from 1953-56, working on the design of the fast recycling high pressure cloud chamber. After two years as a development engineer in the Infra-red Group at EMI Ltd., he returned to the Department as a Research Assistant to develop automatic devices for the measurement of tracks in nuclear emulsions, bubble and spark chamber photographs, and became a Lecturer in 1962. The group was originally known as the Automatic Methods Group, but by 1968 it had combined with the Data Machines Development & Maintenance Group to form the Technical Physics Group, which occupied the ground floor of the UCL Annexe in Flaxman Terrace. Facilities included electronic and mechanical workshops, dark rooms, a chemical and a clean laboratory, a drawing office, and offices for staff and research students. The technical services provided for the department and, to a limited extent for other departments in UCL and the University, included design and construction of special purpose circuits and equipment, provision of printed circuit boards and a wide range of thin film devices, produced by means of a 19" vapour coating and r.f. sputtering plant. Some development work, supported by the SRC, was also carried out on gallium doped germanium in an attempt to produce high sensitivity, low noise equivalent power, infra-red bolometers for the Infra-red Group.

Having developed his own research work into the general field of pattern recognition, or image processing, both from the theoretical and experimental point of view, Duff founded and then became the Organising Secretary of the national Pattern Recognition Group. Formed in 1967, it included representatives of nearly all the pattern recognition groups in England and met thrice yearly at UCL. Between 1971 and 1975 he received from the SRC grants totalling c. £70,000 for the investigation of parallel processing networks, a programme involving collaboration with scientists at the Laboratorio di Cibernetica, Naples, the University of Maryland, USA and the University of Sao Paulo, Brazil. A grant was also made for the development of an automatic method for optical recognition of vehicles during a traffic census. Further grants of c. £100,000 each were made in 1976 and 1978 respectively for the design and assessment of the fourth in the series of Cellular Logic Image Processors, namely CLIP4, and then the development of the system. CLIP4, the first largest working processor array constructed, was the winner of the British Computer Society Technical Award in 1985, the year when Duff was appointed the first Professor of Applied Physics in the department.

The first development by Duff was the Digiscat, a digitally controlled device providing a semi-automatic method for the measurement of multiple scattering of particle tracks in nuclear emulsions. The operations required for the measurement of multiple scattering by constant cell and constant sagittal methods were performed automatically each time an operator set a crosswire onto the track and pressed a footswitch. A printed list of y coordinates, their second differences and the sum of the modulii of the second differences were provided; a punched tape was also available. With J. Cox and L. J. Townsend an automatic following microscope was developed to search for, find, follow and read co-ordinates of black, grey and minimum tracks in nuclear emulsions with following speeds up to 10 mm. per min. Being particularly suitable to computer control, it was transferred to the Centre for Nuclear Research, Strasbourg for further development on-line to a computer. A digitised microscope for the measurement of bubble chamber track photographs was designed with C. J. Robinson, the coordinates points of tracks being recorded with an accuracy of ±211/2 microns over a measuring area of 20 cm2. Six microscopes were constructed, the last four being provided with a small plug-in unit at the back of the central control chassis to enable changes in the logic to be made for the analysis of spark chamber photographs. Then they devised a polar flying spot scanner to provide an intermediate speed measuring device for bubble chamber photographs. The scanner examined film in the neighbourhood of a vertex and, by means of a set of concentric circles, recorded the polar coordinates of sets of points at frequent intervals along each track radiating from the vertex. In all of the devices it was necessary at some stage to use human operators, e.g. to select photographs worthy of measurement or to guide the device to make measurements on relevant parts of the photograph. They lacked some form of built-in pattern recognition capability in the recording or scanning system. Hence by the mid sixties the Group commenced a study of pattern recognition, both from a fundamental point of view and also with the aim of constructing certain pattern recognition systems.

The research programme under the general heading 'Pattern Recognition Matrices' was originally divided into four parts: a preliminary study of existing techniques for the design and construction of logical networks with many elements; application of one of these techniques to the design of a network for vertex detection in bubble chamber photographs; construction of the vertex detection system; and a long term study of logical networks. Appreciating that human recognition of visual patterns is dependent on the operation of a highly elaborate parallel array of photodetectors, coupled through to many layers of parallel processing nervous circuitry, it was decided to restrict consideration to systems using multiple parallel inputs with highly interconnected logical arrays and using components which were intrinsically capable of microminiaturization. A library of Fortran subroutines was written, optimized and stored on a magnetic disk for use on the IBM 360/65 computer, the subroutines simulating many of the more important, parallel processing pattern recognition algorithms. The library was intended to test pattern recognition schemes in a range of practical applications. There followed a self-organising programme replacing the intuitive selection and application of algorithms by a systematic series of evaluations of the input data resulting in optimal selection of subroutines from the library.

B. M. Jones and L. J. Townsend collaborated with Duff in producing UCLPR1, the first parallel processing recognition system designed to find vertices in bubble chamber photographs. It was originally intended as a preliminary stage of processing to precede the polar scanner device. UCPR1 was a fixed logic, 400-processor system arranged as a 20 x 20 square array of photodetectors onto which were projected charged particle images. The outputs from the photodiodes, suitably thresholded, were first summed over three by three windows and then over a five by five ring of outputs from the first summation. Finally a global threshold was applied, reducing from a maximum until at least one output exceeded the current threshold level, when one or more miniature indicator lamps lit up in the corresponding positions in the output array indicating the approximate position of a vertex in the input image in about 20 ms. With a small circuit modification to ensure that detected points were elements of the input particle track image, the same system operating with an increasing threshold was able to locate line ends. By combining the two functions and by partitioning the output into regions, simple recognition of line figures, such as a subset of alphanumerics, was achieved. However it soon became clear that a simple four-layer processing array, comprising input, two summations and output, was only applicable to a few elementary tasks. Moreover the hand-assembled multilayer printed circuit boards were too restrictive. Consideration was given to the possibility of constructing an array with ten or more layers of logic, each performing a fixed function but allowing data to be moved in either direction between layers, but the technical difficulty of making the necessary connections between the layers was too formidable.

Discussions with Prof. S. Levialdi of the Laboratorio di Cibernetica, Naples, who had shown that simple array of switches, connected to detect closed loops in binary figures, was capable of passing information between processors over long distances in the array, led to a study of the intrinsic processing capability of an array of processing elements containing the smallest set of components consistent with the objective: input and output for image data, paths between adjacent processors, and means for inverting or switching on or off the outputs from the processors. A processing cell incorporated a two-pole, double throw toggle switch, a neon indicator with series resistance, and diodes linked to input and output buses surrounding each cell. A trial 5 x 5 cell array was constructed and at the same time a Fortran simulation was written and linked to a Monte Carlo programme exploring arbitrary connection schemes, chosen at random and applied to a standard test image. In a typical result, the programme taking about 30 minutes in the IBM 360 computer, c. 4000 trials generated c. 70 schemes each with different processing properties, and all 10 schemes which had been devised and wired into the actual array emerged from the Monte Carlo search after about 20 minutes. The diode array proved valuable for developing ideas about arrays of mesh-connected processors, but attempts to describe propagation algebraically were thwarted by the bidirectionalty of the diode paths for signals of opposite polarity. This led to the specification of a processing element in terms of pure logic functions rather than real circuit components.

The translation of the logic specification into the then newly available small scale integrated circuit led to the building of the first Cellular Logic Image processor, CLIP1. The processing element circuit consisted of eight two-input and two four-input NAND gates in three small scale integrated circuit packages. One hundred elements were mounted on a large printed circuit board to form a 10 x 10 array in which each element was connected to its nearest neighbours. A binary image, generated by a flying spot scanner, was stored in the input memory, a shift register. One of three possible functions was selected by appropriate control lines and the contents of the shift register connected to the array element inputs through 100 parallel output lines, the output data being buffered before re-entry to the shift register for display. The three functions chosen were extraction of the contents of closed loops of 1-elements, extraction of sets of 1-elements connected to the array border, and extraction of the outer edges of objects composed of 1-elements. Images were displayed by modulation of the brightness of a 10-line raster on the display oscilloscope. The input image was alterable pixel by pixel by means of a light pen interacting with the display of the input image stored in the shift register.

In CLIP2, a 16 x 12 hexagonally-connected array of processing elements, every element comprised two programmable Boolean processors each implementing independently the full set of functions of two inputs. The output of one processor was transmitted to its six neighbours, whilst that of the other went into an image memory for subsequent further processing or display. The two inputs were either both binary images or else a binary image at one input and the Ored interconnection signals at the other. Additional circuits allowed a second image to be Ored in with the the interconnection signals at the second input. As before, the input image was generated by means of a flying-spot scanner and light pen. Instructions were entered manually as 12-bit words and stored in a 32-word memory. As had been anticipated from the outset, the system was severely limited by the non-directionality of its operations. However its study, which was completed in 1972, led to the processor enhancement required to enable the array capable of performing any image operation.

This enhancement appeared in CLIP3, the interconnection structure between processors being improved by individually gating each direction, then 6 or 8 to provide hexagonal or square connectivity, and by replacing the OR gate by a threshold gate. The instruction word was increased to 24 bits and the instruction memory to 256 words; 16 bits of local image memory were provided at every processor, and various modes for loading data into this memory were allowed. Many programmes were written for CLIP3, ranging from conventional image processing to non-image operations such as maze solving, electrostatic field calculation, and lay planning - fitting together garment patterns for the economic use of cloth. By constructing a scanning system covering a 96 x 96 pixel image with the 16 x 12 processor array, the image area was increased sufficiently to enable programmes to be written to process grey-level images by the use of bit-serial algorithms.

In CLIP4 the processor specification was refined to produce a significant improved performance with the view to fabrication as a large scale integrated circuit so that larger arrays could be built at a reasonable cost. The performance of the scanned version of CLIP4, some 3000 times slower than CLIP3 itself, led to the 96 x 96 processor array, which overcame the loss of speed in the scanning operation. A chip including eight processors, each with 32 bits of local memory, was designed, the target price in 1974 being £6. However a full array of 96 x 96 CLIP4 circuits was not available until some 6_ years after placing the design contract. The CLIP4 system consisted of an array of 9216 bit-serial processors configurable as either a square or hexagonal array, interfaced to two framestores holding 6-bit images. The input store was loadable from a variety of television camera optical workstations via an A/D converter sampling the central part of a non-laced standard television frame; the output memory offloaded through a D/A converter for display on a standard television monitor, means being available for mixing, at variable intensities, the original analogue image and one or other of the input or output digital images. Communication with CLIP4 was via a DEC PDP-11 computer operating under UNIX. Although the serial host was time-shared, CLIP4 itself was only available to one user at a time, but control could be switched to another within seconds and the UNIX file system enabled users to keep track of the locations of both their programmes and their image data.

In the preface to 'Cellular Logic Image Processing', edited by Michael Duff and Terry Fountain, Duff traces the origins of the Image Processing Group from the Digiscat project in 1958 through the development of interest in all types of images to the extensive studies of computer architectures designed specifically for the analysis of two-dimensional data arrays, the emphasis in the CLIP programme being the building of systems primarily to study the relationships between architectures and algorithms. Various aspects of the CLIP system are described in representative extracts from the Ph.D. theses of some of the postgraduates using it in the five years after its commission, namely 'Basic Clip Processing' (S. D. Pass); 'Propagation in Cellular Arrays' (G. P. Otto); 'Software for CLIP4' (A. M. Wood & D. E. Reynolds); 'Serial Section Reconstruction' (H. H-S. Ip); 'Colony Counting and Analysis' (D. J. Potter); 'Computer Tomography' (K. A. Clarke); 'Motion Analysis' (A. M. Wood); and 'Automatic Segmentation' (D. E. Reynolds). In the final chapter Fountain, who directed the construction programme for the CLIP system, describes the CLIP7 project aimed at high-resolution (512 x 512 pixel) images processable at CLIP4 rates, and investigation of the concept of local autonomy within an array of processors, including alternative system architectures - particularly three-dimensional structures having novel connectivity nets.

Molecular Beam Group

This group started work in 1967 as a joint project with the Department of Chemistry, the main object being the investigation of some low energy atomic and molecular collision processes involved in chemical reactions. Its members were Profs. A Maccoll and D. J. Millen from Chemistry and Prof. Massey, Drs. S. J. B. Corrigan and J. Wilson, and research students G. D. Lempert and C. R. Howard from Physics. In order to study a range of reactions without the limitations imposed by the use of surface ionization detectors, a detector using electron impact ionization followed by mass analysis was used. The factors determining the signal to noise ratio of such a system were investigated by means of a commercial quadrupole residual gas analyser arranged as a molecular beam detector in an ultra-high vacuum system. The analyser was also used to explore a modulation system to improve discrimination against signals arising from ionization of the residual gas in the chamber. An apparatus was constructed in which two intersecting beams were formed by nozzles working under hydrodynamic flow conditions, it being known that such suitably designed nozzle sources gave very intense beams with velocity distributions much narrower than those from the Knudsen type of source; pumps capable of dealing with the large rates of gas flow were essential. From the fundamental point of view it was very important to make a detailed study of the reactive scattering of hydrogen atoms by the molecules H2 and D2 since it was only possible in such simple cases of comparing experiment with theory.

Investigations by Physics research students included a study of the velocity dependence of the total collision cross-sections of He-Ar, He-N2, He-O2, He-CH4, He-CCl4, Ne-Xe and Ne-Kr at thermal energies by observing the signal intensities due to the different velocity components of a molecular beam of one gas as it passed through a chamber at room temperature containing the other gas at different pressures (G. D. Lempert); the development of an arc-heated supersonic molecular beam source producing Ar beams with energies in the range 1.8-3.0 eV., Mach No. 5-6.5 and intensities of c. 2 x 1019 mol str-1 sec-1 observed and 2 eV H beams with Mach No. and intensities of c. 5 and 1020 mol str-1 sec-1 predicted (L. S. Marvin); and a study of the dissociation of CO2 by an electric swarm in a Townsend discharge and also by radiation of wavelength 1849 Å (P. Papacosta).

Survey of Research B: Theoretical

Atomic Physics & Astrophysics Group

The leader of this group, Michael John Seaton, on obtaining first-class honours in physics in 1948, declined an invitation to join Andrade's research team in favour of going over to the Mathematics Department to work under the supervision of David Bates. Between 1949 and 1951 during the work for his Ph.D. on quantal calculations of some reaction rates and their applications to astrophysical and geophysical problems he published six papers, three in the Monthly Notices of the Royal Astronomical Society and three in physics journals. On moving back to the Physics Department in October 1950 with Massey he continued with his research in atomic physics and astrophysics with great enthusiasm and skill to become one of the leading international authorities in the field, understanding the detailed methods for the calculation of atomic data and the requirements for these data in astrophysics. Seaton spent the 1954-5 session at the Institut d'Astrophysique in Paris, thus beginning a close association with H. van Regemorter and what was to become a close collaboration between UCL and the Observatoire de Paris at Meudon. Later this collaboration was extended to include the Observatoire de Nice. In 1961 he visited the University of Colorado at Boulder when the Joint Institute for Laboratory Astrophysics was being established, and in 1964 he was appointed a Fellow-Adjoint of the Institute in recognition of his contributions to its scientific activities; there followed an active collaboration with JILA in both atomic physics and astrophysics.

By the early seventies the group contained some twenty members including Drs. Gillian Peach and David Moores as lecturers, Hannelore Saraph as senior programmer, research fellows, visitors from other institutions and research students. Highlights included the development of some general computer programmes for the calculation of properties of highly ionized atoms, good results being achieved for the energy levels by making allowance for fairly complicated relativistic effects; calculations were also made on other properties such as radiative transition probabilities, and collisional excitation or ionization cross-sections. The development of generalized quantum defect theory and its application to problems in atomic structure and in electron-ion scattering, including radiative transition probabilities and dielectronic recombination led to a series of fourteen papers by Seaton and his collaborators over some twenty years. Work in astrophysics was mainly concerned with the properties of the solar corona, gaseous nebulae and the interstellar medium, quasistellar objects, and hot stars. Interest in the properties of the central stars of planetary nebulae led to a joint paper with R. J. Harman obtaining for the first time a well-defined track for these objects on the Hertzsprung-Russell diagram; they showed that these hot stars represented a natural stage in stellar evolution.

Some of the fields in which Seaton (and his group) have worked are described in articles by some of his colleagues and former students in 'Atoms in Astrophysics', published by the Plenum Press, to honour his sixtieth birthday on the 16th of January 1983. Edited by Messrs. P. G. Burke, W. B. Eissner, D. G. Hummer and I. C. Percival, these articles are on 'Low-Energy Electron Collisions with Complex Atoms and Ions', by P. G. Burke and W. Eissner; 'Numerical Methods for Asymmetric Solutions of Scattering Equations', by D. W. Norcross; 'Collisions between Charged Particles and Highly Excited Atoms', by I. C. Percival; 'Proton Impact Excitation of Positive Ions', by A. Dalgarno; 'Applications of Quantum Defect Theory', by D. L. Moores and Hannelore Saraph; 'Electron-Ion Processes in Hot Plasmas', by J. Dubau and H. van Regemorter; 'The University College Computer Package for the Calculation of Atomic Data - Aspects of Development and Application', by H. Nussbaumer and P. J. Storey; 'Planetary Nebulae', by D. R. Flower; and 'Forbidden Atomic Lines in Auroral Spectra', by D. R. Bates.

The modern theory of low-energy electron collisions with complex atoms and ions may be traced to Seaton's 1953 classic study of the Hartree-Fock equations for continuum states and his application of them to calculate transitions between the 3P, 1D, and 1S terms of the ground-state configuration of atomic oxygen. The calculations on atomic oxygen were extended to O II and N II and N I, providing the first-time quantitative estimates of the electron impact excitation and de-excitation of the forbidden lines of the ground state configurations for these systems. These results were of fundamental importance in many applications, e.g., forbidden atomic lines in auroral spectra and gaseous nebulae, as illustrated by the aforementioned articles of Bates and Flower. Seaton's theory required the solution of sets of coupled integro-differential equations for the motion of the scattered electron. Since it was not possible to solve these equations exactly, Seaton developed approximate methods of solution and obtained results very close to the later exact numerical ones. Following the development of the general theory of e-H excitation by Ian Percival and Seaton, the latter initiated in late 1956 the intensive effort at UCL required to solve the resultant equations. This led to the general computer programme for e-H scattering on the English Electric Pilot ACE and DEUCE computers by Phil Burke, his wife Valerie, Percival and R. McCarroll. In the late sixties Seaton decided to exploit the new generation of computers to obtain accurate data on atomic structure and atomic collisions for application to the interpretation of solar spectra acquired by rocket and satellite launchings. Most of the lines arose from electric dipole transitions in highly ionized atoms. The corresponding collision strengths could be calculated with sufficient accuracy in the distorted-wave approximation provided good bound-state functions were produced; these functions would then also allow transition probabilities and oscillator strengths to be calculated. The outline of such a project in 1967 led to the programme, STRUCTURE, for calculating atomic wave functions by his colleagues, W. Eissner and H. Nussbaumer, in 1969. The extension of STRUCTURE to include relativistic corrections to the energy levels by M. Jones and the further extension allowing the calculation of transition probabilities by Eissner and Nussbaumer resulted in SUPERSTRUCTURE. Hannelore Saraph developed the programme SIMMEG in the late sixties for the transformation of reactance matrices calculated in LS coupling to collision strengths, and then JAJOM for such use in intermediate coupling. In their 1972 paper on computer programmes for calculating electron-atom collision cross-sections, Eissner and Seaton were mainly concerned with the excitation of neutral atoms and positive ions at near-threshold energies for astrophysical application, two approximations being discussed. The distorted wave approximation was applicable when the coupling of the integro-differential (ID) equations is not too strong, i.e., for highly ionized systems (in practice for more than about two or three times ionized). The ID approximation (often called the 'close-coupling' approximation) could be used when the DW method failed. A prototype version of IMPACT, a general computer programme based on numerical methods to replace the ID equations by a system of linear algebraic equations, was working in 1969, but the final version was not published until 1978 by M. A. Crees, P. M. H. Wilson and Seaton. Other programmes in the UCL package include PHOTUC written by Hannelore Saraph to calculate photoionization cross-section from solutions of the close-coupling equations, and RANAL, originally written by Seaton, for fitting calculated reactance matrices as functions of energy and the extrapolation and interpolation of scattering data. Throughout the package programmes were written for certain types of problems and not particular cases, Seaton's intention being to get away from the "one man - one cross-section" approach to programming.

The departmental list of publications for the 1954-55 session, which he spent in Paris, records twelve papers by Seaton, three being in Comptes Rendus. Two of the three papers in Comptes Rendus were on the approximate calculation of atomic photoionization cross-sections, the second being his first publication on quantum defect theory. Then in 1958 he extended the theory to continuum states, providing a basis for general formulae for radiative transition probabilities applicable to singly excited states. There followed the extension to bound-free transitions by A. Burgess and Seaton, giving their general formula for calculating atomic photoionization cross-sections, and the general formula of Gillian Peach for the calculation of absorption cross-sections for free-free transitions in the field of positive ions. She revised the Burgess-Seaton formula, and wrote a general computer programme, which was available on request, for calculations on the basis of her general formula. Then in 1971 she published extensive results for continuous absorption coefficients for non-hydrogenic atoms. Detailed comparisons of the results of the Peach programme and the close-coupling method for photoionization were made for O IV by Hannelore Saraph showing agreement to within 10% for the background cross-section from states 2s2nl, including nl = 2p, and from 2s2pml states the Peach formula results were not generally reliable for ml = 2p, but quite good for m > 2. Although the one-channel theory was very successful for calculating photoabsorption rates, it soon became evident that a multi-channel theory, applicable to systems with more than one electron in open shells, was required for interpretation of a wider range of phenomena. The first paper on multi-channel defect theory appeared in the Proceedings of the Third International Conference on the Physics of Electronic and Atomic Collisions held at UCL in 1963, the authors being O. Bely, Moores and Seaton. There followed a series of thirteen papers, QDT I-XIII, by Seaton and his collaborators between 1966 and 1982, deriving powerful interpolation and extrapolation techniques to describe perturbed Rydberg series and complicated resonance structures. In QDT I Seaton generalised the theory to the many-channel case and included a number of new results, and in QDT II he gave some illustrative examples of applications of one-channel and two-channel problems, an improved value being obtained for the ionization energy of He. QDT III by Bely dealt with the scattering of electrons by He+ with some inclusion of the effects of the dipole coupling potential in the analytic description. In QDT IV Moores applied the many-channel theory to the calculation of radiative transition probabilities and photoionization cross-sections of Ca, including the effects of autoionizing states. A semi-empirical method was applied, using experimental data for the perturbed series. QDT V by Moores was concerned with the autoionizing and bound states of Be. N. A. Doughty, V. B. Sheorey and Seaton extended the theory to extrapolations along isoelectronic sequences in QDT VI. Seaton in QDT VII developed the theory for the analysis of complex resonance structures in inelastic electron-ion scattering, obtaining expressions for the widths and positions of resonances and for the cross-sections averaged over resonances in regions just below the excitation thresholds. In QDT VIII P. de A. Martins and Seaton considered resonances in the collision strengths for O+ 2p3 2D3/2-2D5/2. D. W. Norcross and Seaton introduced the concept of a complex quantum defect and applied it to an analysis of the Be spectrum in QDT IX. The many-channel theory was applied to the problem of the calculation of photoionization cross-sections, including detailed resonance analysis, in QDT X by J. Dubau and J. Wells. In QDT XI Seaton gave a summary and clarification of the development of the theory and clarification of some of its aspects. Dubau in QDT XII extended the theory for cases of dipole coupling potentials, overcoming the problems encountered in QDT III. In QDT XIII Dubau and Seaton gave further consideration to autoionization processes in excitation and photoionization processes of importance in the study of dielectronic recombination.

In 1957 Seaton with Ian Percival gave the first rigorous treatment of the partial-wave theory of electron-hydrogen collisions and in 1960 they collaborated with Leonardo Castillejo in the consideration of the theory of the long-range interactions between electrons and hydrogen atoms, showing that the leading term of the interaction at large separation was a/(2r4), where a is the static dipole polarizability of hydrogen. Then in 1977 Seaton with L. Steenman-Clark showed that the next long-range term was a'/(2r6), where a' is linearly dependent upon the energy of the elastically scattered electron and can be calculated analytically; this was followed in 1978 by a numerical study of the non-local nature of the effective potentials for electron-hydrogen scattering. In her comprehensive review of interactions in atoms and diatomic molecules, Gillian Peach cites two of her own papers, namely (i) a consideration of the model potentials involved in low-energy scattering of excited helium atoms by rare gases (1978) and (ii) an examination of the relative merits of model potentials and pseudopotentials and their application to problems of atom-atom scattering (1982), as illustrations of her particular interest in the two-centre system.

In his 1955 paper on cross-sections for 2s-2p transitions in H and 3s-3p transitions in Na produced by electron and proton impact Seaton pointed out that, when the energy of DE of a transition is much less than the mean thermal energy kT, the rate coefficient for proton impact excitation of neutral targets is greater than that for electron excitation by a factor equal to the square root of the ratio of the proton to electron mass. Thus proton collisions are effective in redistributing angular momenta in high-lying Rydberg levels. In 1962 Seaton applied the impact parameter method to obtain cross-sections for optically allowed transitions by electrons. It consists of a series of approximations that provides simple analytical forms and is therefore particularly suitable to collisions involving highly excited states, the results within their range of validity being adequate for many astrophysical and other applications. In 1964 there followed three papers on recombination spectra: (i) R. M. Pengelly solved the capture cascade equations for a hydrogenic system in the limit of low densities, but the agreement with observations in planetary nebula were unsatisfactory, leading to the conclusion that l-changing collisions should be taken into account; (ii) Pengelly and Seaton calculated the cross-sections for such collisions using a modified form of the impact parameter method; and in (iii) Seaton used them in a further study of recombination spectra. In the excitation of positive ion targets the Coulomb interaction diminishes the rate coefficients for proton impact while enhancing those for electron impact. In (ii) it was shown that for collisions involving l-changing of He+ by protons the effects of the Coulomb interaction were small for large values of n at the temperatures of the order of 104 K, characteristic of astrophysical plasmas. In 1964 Seaton also investigated the proton impact excitation of coronal lines, showing that the excited fine-structure level, Fe13+(3p2P3/2), may radiate with the emission of the coronal greenline at 5304.3 Å. He showed that the proton excitation rate exceeds the electron excitation rate at temperatures above 1.3 x 106 K. At the end of his article Dalgano points out that although most of Seaton's research has involved electron impact phenomena it was his aforementioned studies that established the importance of proton impacts with the ionized constituents of astrophysical nebulae and laboratory gases and initiated a lengthy series of calculations, particularly on proton-impact excitation of fine-structure transitions, which broadened to include metastable transitions and ionization processes, all of which participate in determining the ionization structure and the emissivity and energy loss from hot plasmas.

Work by the group on gaseous nebulae started with the extension of Seaton's 1953 calculations on atomic oxygen to O II and N II and then to N I providing for the first time quantitative estimates of the electron excitation and de-excitation of the forbidden lines of the ground state configurations of these systems. This was followed by his work on the relative line intensities for [O II] and [S II] 2D to 4S; the interpretation of the Orion spectra; and the relative [O II] intensities (with Osterbrock). On the planetary nebulae there were papers on electron temperatures and electron densities; local density variations; and continuum intensities. The sixties started with his paper on H I, He I and He II intensities, and that on the ultra-violet radiation field of the central stars (with Hummer). There followed eight papers on the ionization structure of planetary nebulae: (i) pure hydrogen nebulae; (ii) collisional cooling of pure hydrogen; (iii) the ionization of helium (Hummer & Seaton); (iv) optical thickness of the nebulae and temperatures of the central stars ( R. J. Harman & Seaton); (v) radii, luminosities and problems (Seaton); (vi) the Lyman continuum problem (D. van Blerkom & Hummer); (vii) the heavy elements (Flower); and (viii) models of NGC 7662 and IC 418 (Flower). A joint paper with Harman obtained for the first time a well-defined track for the central stars on the Hertzsprung-Russell diagram, the final stage of evolution of these exceptionally hot stars being down to white dwarfs, and processes involving neutrino emission probably being responsible for the rapid evolution of the stars. Other papers by Seaton involved excitation of spectrum lines in nebulae by resonant scattering of radiation from the central stars; recombination spectra of gaseous nebulae; abundance of He in gaseous nebulae; distances of planetary nebulae; forbidden line radiation from gaseous nebulae (with Flower); and electron densities in planetary nebulae (with Saraph). With M. Brocklehurst he made a study of radio recombination lines emitted by gaseous nebulae taking into account all relevant collisional and radiative processes, including maser action and pressure broadening. Results calculated on the basis of a spherically symmetric model constructed for the Orion nebula agreed with radio observations. Then with M. Salem he considered the interpretation of continuum flux observations from thermal radio sources, covering continuous spectra and brightness contours, leading to the consideration of three-dimensional models by Salem and the construction of another spherical one for the Orion nebula, which was compared with the previous one. Brocklehurst and Salem wrote a computer programme for the calculation of the intensities and profiles of helium and hydrogen radio recombination lines emitted by a thermal source.

The ionization balance in high temperature plasmas was shown to be very strongly affected by the process of dielectronic recombination. By studying the behaviour of a large number of specific cases a simple general formula was obtained for the estimation of dielectronic recombination rates in low-density plasmas such as the solar corona by Burgess. He also considered dielectronic recombination and the temperature of the solar corona, and, with Seaton, discussed the ionization balance for iron in the solar corona. Their success in explaining the ionization structure of the solar corona led to dielectronic recombination being usually associated with coronal conditions in which collisions dominate ionization and the electron temperature corresponds approximately to the temperature of maximum abundance of the emitting ion. Later Storey carried out calculations to investigate the contribution of dielectronic recombination to line excitation and ionization balance under conditions where the temperature is far too low to cause collisional ionization. The calculation of dielectronic recombination coefficients, bringing together electron scattering, bound-free and bound-bound radiative processes, embodied in one process all the problems that the UCL computer package was designed to solve. The calculated rate coefficients for dielectronic recombination of a number of ions of C, N, and O were found to exceed the corresponding radiative recombination coefficients at Te = 104 K. P. C. W. Davies and Seaton gave a rather general formulation of dielectronic recombination, essentially a generalisation of radiation damping theory, which laid the basis for its development by rigorous quantum mechanical theory, which was carried out by R. H. Bell and Seaton.

Seaton became keen to make astronomical observations and agreed to interchange posts for a year with D. E. Osterbrock. Osterbrock came to UCL for the 1968-69 session and his interpretation of the observed Fe X and Fe XIV lines in Seyfert Galaxies was the first publication using the distorted wave approximation; he also calculated C III collision strengths for the excitation of semiforbidden lines in quasars and nebulae. It was not until ten years later that Seaton started to make observations with the IUE, but soon made up for lost time, collaborating in ten papers between 1978 and 1981 which included observations of novae and nebulae with theoretical interpretations. With J. I. Castor and J. H. Lutz a detailed analysis was made for the central star NGC 6543 finding stellar wind velocities as high as 2100 km/s and mass loss rates greater than five times that attributable to radiation pressure alone. Nova Cygni 1978 was observed for 300 days from the fourth day after the outburst on 7 September 1978. The spectra obtained included emission lines of He II, C II, III and IV; N II, III, IV and V; and O I, II, IV and V. Seaton and his colleagues (D. J. Stickland, C. J. Penn, M. A., J. Snijders and P. J. Storey) analysed the results, finding 88 days after the outburst an electron concentration of 8 x 1013 m-3 and electron temperatures ranging from 9500 K derived from the ionization balance for C III to 14,000 K from that for N V. The derived abundances of He, C, N and O showed that those of the three heavier elements were much greater than in the sun, especially that of N. This was understandable on the basis of production of the nova by a runaway nuclear reaction leading to ejection of a shell of material. Seaton was also involved in two of the best studied nebulae, namely NGC 7662 and IC 418. In an exhaustive study of NGC 7662, J. P. Harrington with Lutz, Stickland and Seaton considered the reasons for the discrepancies between determinations of the temperature of the central stars based upon the Zanstra method and upon UV continuum observations. They recorded 24 UV line intensities ranging from the N V l1240 line to the He II l3203 line. Abundances of C, N, O and Ne relative to H were obtained on the basis of sophisticated models incorporating all the important physical processes after careful attention to the reduction of the UV observations of both the nebula and the central star. The C III l2297 was interpreted as being produced by dielectronic recombination of C3+ via low-lying autoionizing states with the consequence that C/O > 1. A C3+ abundance derived from the intensity of l2297 and a total C abundance almost twice larger than the value deduced from the intensity of the collisional excited resonance line doublet C IV l1550 led to the conclusion that l1550 undergoes dust absorption. Only an upper limit being established for the intensity of Mg II l2800 implied an abundance of magnesium at least 50 times less than the solar value; silicon is also depleted by a factor of c. 4 owing to both elements having been removed from the gas phase by grain formation. Measurements were made of the UV line intensities of C+, C2+, O+ and Mg+ in IC 418 and values of the carbon and carbon ionic abundances were derived from the observed intensities of the l2326 and l1908 relative to Hb and measurements of the O III and N II electron temperatures. There was good agreement with the values of total carbon abundance obtained by Torres-Pembert et al but differences in the abundances of individual ions. Both groups of workers found an enhancement of the C/O ratio of IC 418 compared with that of the sun. They also noted that the observed C+/C2+ ratio was significantly greater than predicted by model calculations. The inclusion of dielectronic recombination in the calculations on IC 418 would tend to bring the two ratios into better agreement.

Seaton's expertise in computing was recognised by his appointment as a member of the "Flower's Committee" which investigated the future needs of computing equipment in British universities; its report, accepted by the Government in 1966, resulted in major changes and led to the Computer Board, setting the pattern for the next twenty years. He served as Chairman of the UCL Computer Board of Management for some ten years, and was a member of the Board of Management of the University of London Computer Centre and of the University's Central Coordinating Committee for Computing Services. For UCL his efforts in 1965 were largely responsible for the installation of the IBM 360/H65 computer at the College with provision for its use by other Colleges. He served as Acting Head of department when Heymann had a sabbatical year at CERN. In 1968 he played a major role in establishing and supporting the international journal Computer Physics Communications, both as an Advisory Editor and contributor of programmes. He was involved in launching the Journal of Physics series in 1968 and became the first Honorary Editor of the B series on Atomic and Molecular Physics. His elections to the Fellowship of the Royal Society in 1967 and UCL in 1972 were followed by the award of the Honorary Doctorate of the Observatoire de Paris in 1976, the Presidency of the Royal Astronomical Society in 1979-81, the award of the Honorary D. Sc. degree by the Queen's University of Belfast in 1982, the Royal Astronomical Society Gold Medal in 1983, and the Guthrie Medal of the Institute of Physics in 1984.

Gillian Peach joined Seaton's group as a Research Assistant in October 1960, having graduated and obtained her Ph.D. degree at Royal Holloway College; she became a Lecturer in October 1966. Having gained an international reputation as a theoretical atomic physicist with special interests in astrophysical applications of the theory of atomic collision processes, she became a Reader in the 1983-84 session. Her comprehensive work in the field of ionisation of atoms and atomic ions by electron and proton impact covered all atoms from hydrogen to argon as well as some iso-electronic sequences; in many cases her results were the first on these ionization cross-sections. Later the data found a wide range of applications by others ranging from the interpretation of features of the atmosphere of Io to processes of interest in energy production in thermonuclear fusion.

The development of general formulae based on quantum defect theory for the photo-ionization and free-free absorption of photons by atoms and atomic ions enabled cross-sections for particular cases to be obtained simply by the insertion of known spectroscopic data for the appropriate atomic system. This work was widely applied to provide estimates of the many thousands of cross-sections required in astrophysical problems. Her extensive tables of continuous absorption coefficients for non-hydrogenic atoms were widely utilized by astrophysicists in the interpretation of stellar spectra.

In the field of the theory of the broadening and shift of spectral lines by pressure effects she covered the first fully quantum-mechanical treatment of the pressure broadening of an atomic spectral line by electron collisions; this required a synthesis of the impact theory of line broadening with the close-coupling approach and the many-channel quantum defect theory for electron-atomic ion collisions.

She developed good model and pseudo-potentials as well as extensive computer programmes for application in the field of low-energy atom-atom interactions. Her article in honour of Seaton's sixtieth birthday is a 58-page review, of the then-current status of the field of long-range interactions in atoms and diatomic molecules.

David Moores entered the Department in October 1959 and on graduation started research on applications of many-channel quantum defect theory under the supervision of Seaton, gaining his Ph. D. degree in 1965. From 1965-67 he was a Research Assistant in Ian Percival's group in the Department of Mathematics at Queen Mary College. His research was undertaken mainly at UKAEA, Harwell in collaboration with Phil Burke; they carried out one of the first accurate calculations of electron-impact excitation of positive ions. He returned to College in 1967 as a Lecturer, joining Seaton's group, and gaining promotion to the Readership grade in the 1984-85 session for his research in theoretical atomic physics, a distinctive feature being work on problems closely related to experimental work.

Following his collaboration with Burke, Moores developed techniques for the computation of scattering amplitudes and various parameters of great value to experimentalists, and that led to studies of electron scattering by alkali atoms and the related problem of photo-detachment from alkali negative ions. Much of the interest in the work arose from developments in laser technology which enabled the detachment cross-sections to be measured with high precision and resolution. Comparison of the theoretical and experimental results provided a good check on methods applied in a wide range of problems in theoretical atomic collision physics.

Some of his most original work was concerned with the electron scattering by molecular systems. The multi-centre nature of molecular systems leads to slow convergence with the commonly used single-centre expansions of the atomic-system type. Moores noted that it is possible to obtain exact electronic wave functions for the simplest molecule, the positive hydrogen molecular ion, using prolate spheroidal co-ordinates, and he showed that the use of such co-ordinates led to greatly accelerated convergence for electron-molecule scattering.

Much of his then most recent work was concerned with electron impact ionization of atoms and atomic ions, the theory of which is very difficult owing to the need to allow for correlations between two electrons in the continuum. Rates for impact ionization were urgently required for studies of laboratory and astrophysical plasmas; experimental results were available for some ions, but for many one had to rely on calculated values and various semi-empirical approaches. The distinguishing feature of Moores's work in this field was to make accurate ab initio calculations for complex atomic systems, calculations greatly superior to any previous ones. His 45-page article with Hannelore Saraph in honour of Seaton's sixtieth birthday follows the evolution of quantum defect theory and its applications from the 1960s, the emphasis being on work inspired by developments at UCL.

High Energy Physics Group

This group was really formed in 1960 when James Hamilton came from Christ College, Cambridge to take up the second established chair in the department. His interests had been particularly in the theoretical side of nuclear physics and fundamental particles, and he was the author of the book on "The Theory of Elementary Particles", published by the Oxford University Press, 1959. However he left at the end of the 1963-4 session for a Professorship at the Nordic Institute for Theoretical Physics in Copenhagen. Meanwhile he had established a thriving group studying low-energy pion-nucleon scattering and pion-pion interactions, sponsored in part by the Air Force Office of Scientific Research, OAR, through the European Office, Aerospace Research, United States Air Force. By the time he left, the group consisted of two lecturers, Drs. A. Donnachie and W. S. Woolcock, two research assistants, Drs. A. T. Lea and G. C. Oades, and seven research students. Incidentally Woolcock came to UCL with Hamilton to complete the last year of his Ph.D. degree, being given leave of absence from Cambridge University; he was appointed lecturer at UCL in 1963, having in the meantime being lecturer in the Mathematics Department of the University of Queensland. Donnachie returned to Glasgow in 1996, having spent his last session on leave at CERN. Leonardo Castillejo returned in January 1967 to take up the chair left vacant by Hamilton's departure to Copenhagen and become head of the group. Dr. Zienau and research students, H. Osborn and P. Cordero, moved over from the General Physics Theoretical Group, and Drs. C. Wilkin and B. R. Martin joined the group as lecturers in 1968. Woolcock left in 1968 to take up an appointment at the Institute of Advanced Studies, Australian National University, Canberra.

A method was developed for obtaining information about pion-pion interactions from low-energy pion-nucleon scattering based on the dispersion relations for the partial p-N amplitudes. It was shown how low-energy s-wave p-N scattering could be broken down into its constituent contributions from T=0 and T=1 p-p interactions, core (short-range) effects, crossed a33 resonance effect, and rescattering. Then the same was done for the p-wave p-N scattering but with the addition of the long-range Born term. The p-wave p-N breakdown showed that the position of the (3/2,3/2) resonance could not be calculated without taking the T=0, J=0 p-p interaction as well as the short-range attraction. T.D. Spearman, P. Menotti, G. C. Oades and L. L. J. Vick collaborated with Hamilton in these researches, Oades and Vick being UCL research students. In a 50-page article (Rev. Mod. Phys., 35, 737,1963) Hamilton and Woolcock give an account of the application of single variable dispersion relations to calculate the main parameters of low-energy pion-nucleon scattering and the low-energy phase shifts, the input data being information on the total cross-sections and the dominant resonances of the p-N system. They discuss in particular the high-energy behaviour, the subtractions and sum rules in the application of dispersion relations, as well as the convergence of the Legendre series for the expansion of scattering amplitudes in the partial waves. The rates of convergence are of basic importance for the prediction of low-energy pion-nucleon phase shifts by dispersion relations. An account is also given of Woolcock's calculations in his 1961 unpublished Cambridge Ph.D. thesis, and other determinations, of the parameters of low-energy pion-nucleon physics. Finally the fixed momentum-transfer dispersion relations are used to predict the s-wave and p-wave pion-nucleon phase shifts at low energies.

On the photodisintegration of the deuteron, Donnachie and P. J. O'Donnel extended the former's 1961 calculations of the differential cross-sections and polarizations for photon laboratory energies up to 130 MeV by including more transitions, final-state couplings and investigating retardation effects. The results were found to be insensitive to the deuteron D-state probability but markedly dependent on the omission or inclusion of retardation, even at low energies. Detailed comparison with experiment showed that the best fit over the whole energy range to the available data was achieved with a 6% deuteron D-state probability and with retardation included. The deuteron photodisintegration process was used to study nucleon-nucleon phase shift parameters. In the photoproduction of pions from nucleons, Donnachie and G. Shaw used fixed-momentum dispersion relations to evaluate transition amplitudes which lead to final s-, p- and d-wave scattering states. Using pion-nucleon scattering phase shifts up to 700 MeV, the coupled integral equations for the dominant M1+, E0+ transitions were solved explicitly by an iterative method. Good agreement with experiment was obtained up to 550 MeV photon laboratory energy and a much better determination was made of the g-r-p coupling constant. Donnachie and Hamilton developed a variational method of solving p-N dispersion relations, an application of the method confirming an earlier analysis of s-wave p-N scattering. With Lea they developed a peripheral method, in which the very-short-range part of the interaction was almost completely suppressed, for predicting p-N phase shifts up to moderate energies. Precise values were given for the p-, d-, and f-wave phase shifts, with the exception of p11, up to 400 MeV, and the general behaviour reproduced up to around 1 GeV. The 600- and 900-MeV p--p resonances were identified with the D13 and F15 amplitudes respectively, and the 1.35 GeV p+-p resonance probably in F37.

Donnachie and Lee collaborated with P. Auvil and C. Lovelace of Imperial College in a phase-shift analysis of pion-nucleon scattering up to 700 MeV, finding a phase family in the 300-700 MeV region in excellent agreement with practically all the experiments, and also with predictions from partial wave dispersion relations.

Using the techniques of energy-independent phase shift analysis, with simultaneous fitting to the partial-wave dispersion relations, Donnachie, Lea and Lovelace obtained a unique solution to p+p scattering below 1100 MeV pion laboratory energy. The most striking feature of this solution was that the main content of the 800 MeV shoulder was an inelastic S31 resonance, such an object being required by SU(6) in the 70- multiplet to which the known D13 resonance belongs. Donnachie, Kirsopp and Lovelace carried out a sophisticated analysis of low energy experimental results, including those of the UCL spark chamber group, on p elastic scattering. On the basis of phase shift analyses at 59 energies, linked with partial wave dispersion relation fits,18 nucleon resonances were proposed in the mass range 1236-2265 MeV, 9 in the range 1680-2190 MeV being new ones, all with very small branching ratios to the elastic channel.

Donnachie and Hamilton showed that the quantum numbers of the 200, 600, 900 MeV and 1.35 GeV nuclear isobars are determined by the systematic properties of the longer range part of the pion-nucleon interaction, thus making possible the understanding of the Regge plot in terms of the interactions which produce the several families of isobars. They also showed that the requirement of dispersion relations for partial-wave amplitudes to obey a high-energy boundary condition gave rise to a unitary sum rule, which could be used to estimate the short-range parts of the pion-nucleon interaction. This made possible accurate predictions of the non-resonant p-, d- and f-wave p-N amplitudes up to around 650 MeV in good agreement with an analysis of experimental data.

The partial-wave expansions of invariant amplitudes for various scattering processes involving spin 1/2 particles were studied by Woolcock and G. Rasche using a general representation for the Dirac gamma matrices. They extended the study to cover the general formalism of some scattering processes involving photons and investigated ambiguities in the solution of partial-wave dispersion relations in which the left-hand cut contribution is approximated by a finite set of poles. Woolcock showed that the necessity for subtractions in dispersion relations in order to make the integral over the left-hand cut converge implies an oscillatory behaviour of the discontinuity across that cut, the violence of the oscillations increasing with the number of subtractions. He investigated the properties of dispersion integrals (Stieljes Transforms), firstly obtaining results for their asymptotic behaviour for large z and then extended them to prove theorems holding uniformly for all directions in the complex plane. Special additional assumptions, to hold for all sufficiently large values of the argument of the function, were required to obtain the extended results.

G. D. Froggatt made an analysis of the Regge Pole Model for Vector Meson production with G. V. Dass (from RHEL), considering the reaction pN -> eN and then KN -> K*N. An analysis of (+-) dipion production, which indicated that the extrapolated production cross-section did not vanish at t=0 as it would for pure one-pion exchange, led him and D. Morgan (RHEL) to propose a model for the phenomenon, giving a new prescription for performing Chew-Low extrapolations. The Reggeized Deck amplitude for the pN -> prN reaction was partial-wave analysed in the A1 region of the pr subsystem by Froggatt and Gisela Ranft (on attachment to the group from RHEL). It was found that the state was predominantly 1+ s-wave, in agreement with a local duality interpretation, and this was followed by a general discussion of the spin-parity structure of a two-particle subsystem for a double-Regge expansion of a three-body production amplitude. Gisela Ranft then published four papers on a review of the current evidence for multi-Regge pole processes: the annihilation reaction p + p -> 2p+ + 2p- and a multi-Regge model; the double-Regge model and an 'anticornering' effect in three-particle production processes; and a double-Regge analysis of the reaction K-p -> K-wp.

A study of composite particles in field theory was undertaken resulting in the following papers: 'Z=0 and compositeness', 'Poles of the two-body Green function', 'Conditions for composite particles with special reference to Lagrangian field theory', 'Relativistic centre of mass variables for two particle systems with spin' and 'Relativistic corrections to non-relativistic two particle dynamical calculations - demonstration of the validity of the Drell-Hearn-Gerasimov sum rule for weakly bound composite particles' by Osborn; 'Equivalence of the Lee and Zachariason models' by Osborn and Zienau; and 'Conditions for compositeness in field theory' by Cordero.

Castillejo received his early education at the international schools in Madrid and Geneva, his family leaving Spain during the Civil War. A year at the Polytechnic in Regent Street, followed by one at Imperial College, resulted in the award of the B. Sc. degree in engineering in 1942. After four years of work on the land, he entered King's College, Cambridge, gaining the B. A. degree in mathematics in 1948. He then joined UCL as a Research Assistant in the Mathematics Department under Massey working on high-energy (83 MeV) nucleon-nucleon scattering and became an Assistant Lecturer in physics in 1950 when Massey assumed the headship of the department. During a year's leave of absence as a U. S. Foreign Aid Administration Fellow at Cornell University in 1954, he collaborated with Dalitz and Dyson on what was to became known as the Castillejo-Dalitz-Dyson ambiguity, which had a major impact on the application of analyticity and bootstrap ideas to particle physics in the 1960s. They realised that it was possible to add arbitrary poles to the denominator function of a scattering amplitude without creating extra singularities in it. In a sense such poles express the physical possibility that stable particles are present even when the interactions are switched off. In 1957 when P. Matthews left Birmingham to join A. Salam at Imperial College, Peierls approached Massey to persuade Castillejo to move to Birmingham at rather short notice. In 1963 he went to Oxford with Peierls, becoming a Fellow of Wadham College. When Massey approached Peierls in 1965 about Castillejo returning to UCL to fill the chair vacated by Hamilton, Peierls wrote "...I am, of course, very distressed about the proposal since I have greatly valued having Castillejo here and would greatly deplore losing him....he would be an excellent person to meet the requirements of the post as described in your letter. He is knowledgeable, energetic, and passionately interested in physics though, of course, along somewhat different lines from Hamilton's; he is excellent and kindness itself with students, and very interested in problems arising from experiments. His chief disability, as no doubt you know, is that he does not publish very much - partly because of his high standards, which make it very hard for him to be completely satisfied with his own results, and partly because he is always so willing to help other people with their problems and worries that he often disregards things which would bring him the greater personal credit. However, this tendency is a disadvantage to him personally and not to the Department to which he belongs." By the time he returned to College, the Annual Reports had listed just two papers, namely the famous CDD one (1955) and the one in atomic physics with Percival and Seaton on exchange effects in the elastic scattering of electrons from hydrogen, formulating the problem in the more consistent time-dependent approach (1960). The next listings were two 1973 papers, the first with B. J. Berriman on 'Comparison of eikonal amplitudes for potential scattering' and the second, the somewhat surprising 'Are there real limits to growth? - A reply to Beckerman,' in the Oxford Economic Papers, 23, with L. S. Brown, H. F. Jones, T. W. B. Kibble & M. Rowan-Robinson. Some six years later, on leave at the State University of New York at Stony Brook, he wrote a paper on 'Little-Group Classification of Gauge Fields', with M. Kugler & R. Z. Roskies in which was proposed a new way to treat the classification of the Yang-Mills gauge fields at a space-time point, the main tool being a consideration of the structure of the Little group which left the field invariant; this approach reproduced the standard classification of the Weyl tensor and of the electromagnetic field. This was followed by he and Kugler investigating a class of solutions of the classical SU(2) Yang-Mills equations, the symmetry of which prescribed a natural set of gauge-invariant degrees of freedom. Meanwhile at Stony Brook he had published a paper on 'Optimal and nearly optimal distribution functions for 4He', with A. D. Jackson, B. K. Jennings & R. A. Smith, in which the properties of the Euler-Lagrange equation obtained by minimizing the hypernetted-chain energy of a boson fluid were studied. A consideration of the asymptotic form of the resulting two-body distribution function g(r) showed that g(r)-1 was proportional to r-4 for short-ranged potentials; the stability conditions for g(r) were expressed as an eigenvalue problem and the relation to the adiabatic compressibility was established. Previous numerical results for liquid 4He were shown to describe an energy minimum. The existence of the low-lying eigenvalues for all l and the nature of the related non-spherically symmetric eigenfunctions suggested the existence of 'crystalline' solutions of the Euler-Lagrange equation. Castillejo then began working on rather specialist esoteric models, closely linked to the more fashionable areas of modern particle theory, much of this work being carried out with Andrew Jackson from Stony Brook. First there was the case of the toroidal nucleus - a doughnut model of a nucleus of 150 quarks which might have a lower energy than a spherical model - the so-called anomalon. Another topological problem was the Skyrme model of the nucleus, in which he investigated the nucleon-nucleon interaction and played an important role in establishing its connection to more familiar meson exchange interaction. Interest in the phase structure of the Skyrme model and its connection to chiral symmetry restoration led to a more general investigation of collective co-ordinates in effective field theories, possible connections to high-temperature superconductivity fascinating him.

Castillejo's undergraduate lectures frequently perplexed the audience owing to his habit of deriving new proofs on the blackboard, yet his tutorials were excellent. The 1976 Departmental Booklet for distribution to schools included a photograph of him with four undergraduates, tutor and students all smiling, during a tutorial on relativity, the caption being 'Someone has spotted the deliberate mistake in the formulae on the blackboard.' He was an excellent supervisor of postgraduates, readily stopping his own work to sort out their problems. After retirement he remained in the department and started demonstrating in the first-year laboratory, critically examining all the scripts.

After graduating and obtaining his Ph. D. degree at Birmingham University, Colin Wilkin spent the next two years as a Research Fellow at CERN and then in 1965 proceeded to the Brookhaven National Laboratory, USA, as a Research Associate, working on the interpretation of the Brookhaven K+-p(d) total cross-sections, followed by participation with an experimental group measuring the angular distributions with spark chamber and counters. He joined Castillejo's group as a Lecturer in 1968. A theoretical physicist with a critical insight into lots of experimental problems and the ability to explain them in simple terms, he was appointed Reader in the 1973-4 session on the basis of his work on a variety of topics - analytic properties of scattering amplitudes, particle symmetries, Eikonal approximations and interaction of elementary particles with nuclei, having become one of the foremost experts in the latter two fields. Many experimental groups throughout the world consulted him for explanation and analysis of their results and suggestions for the direction that their next experiments should take, both high-energy experimental groups at UCL benefiting from his collaboration. His expertise in lecturing led to many invitations to participate in summer schools and his fluency in French being a real asset. At the time of his promotion he was working on the coherent production of particle resonances from nuclei to study the resonance-nucleon cross-section (with the UCL spark chamber group); low energy pion-nucleus scattering and its interpretation in terms of Glauber theory and optical potentials; Coulomb effects in p+/- nucleus total cross-section measurements, and tests of charge symmetry ; and three-body studies in one dimension.

In the late sixties he collaborated with R. H. Bassel in the multiple scattering interpretation of the experiment involving high-energy (1.7 GeV/c) p - a scattering by H. Palevsky et al at the Cosmotron. Then they analysed elastic and total cross-sections of 1 GeV protons on H2, He4, C12 and O16, in conjunction with the corresponding electron scattering measurements, on the basis of Glauber's high-energy approximation, leading to information unobtainable from the electron data alone. Elastic pion-deuteron scattering at 3.65 and 3.75 GeV/c was analysed with C. Michael on the basis of Glauber theory, particular attention being paid to the deuteron D-state and to the spin dependence and phase variation of the pion-nucleon amplitudes; the good overall agreement between theory and experiment could be improved with a larger value of the deuteron quadrupole form factor than that given by a Hamada-Johnston type of wave function. The Glauber theory of multiple scattering was used by Wilkin and N. Straumann to compute the rising-mass spectrum for protons scattered off a deuterium target, the relatively clean separation of the single and double-scattering peaks making possible the determination of the high-energy p-n differential cross-section. Then with O. Kofoed-Hansen the theory was used as a basis for computations to examine the possible effects of short-range dynamical nucleon-nucleon correlations on high-energy hadron scattering on 4He; it was concluded that only very small effects could be expected for elastic and total inelastic scattering of commonly available projectiles. In a paper partly based on his Cambridge Ph.D. thesis, R. Smith collaborated with Wilkin in the development of a theory for large momentum transfer quasi-elastic electron-deuteron scattering using a diagrammatic technique and the derivation of expressions for those triply and doubly differentiated cross-sections which are experimentally measured; the effects of spin were included in an approximate way, and the results compared with relevant recent experiments. N. S. Craigie and Wilkin calculated the large-angle elastic, proton-deuteron, differential cross-sections at around 1 GeV from a triangle graph including as the input pp -> pd amplitude. Although the predicted cross-sections were rather low, the shape was in good agreement with experiment; a maximum in the 180 deg. cross-section was predicted for a proton K. E. of 700 MeV. Ten years later in a paper in which the deuteron stripping reaction A(d,p)B was estimated in terms of the cross-section for pion production with a proton beam A(p,p+)B for the same nuclear states, A and B, Wilkin extended the triangle graph model, stripping data on 2H, 3He and 12C being described successfully for deuteron energies of about 800 MeV. The inelastic scattering of medium-energy pions from carbon was investigated by C. Rogers and Wilkin. They also investigated in a simple model the effect of inelastic scattering on the determination of unstable particle cross-sections, pointing out that information, complementary to that obtained from forward production rates off a variety of nuclei, might be deduced from a production angular distribution off a light nucleus.

During his 1972-4 years at CERN, Wilkin was involved in a number of papers: with F. Scheck in the pion-nucleus optical potential and mesic atoms, the description of pionic atoms by a local pion-nucleus potential rather than the more conventional momentum-dependent potential was considered, it being pointed out that although in simple form they gave remarkably different answers for the energy shifts and level widths of such systems, after inclusion of the effects of short-range correlations, there was very little difference between them, the local potential requiring a slightly more positive isoscalar pN scattering length than the non-local one.

The CERN synchrocyclotron was used by K. Gabathuler, C. R. Cox, J. J. Domingo, J. Rohlin, N. W. Tanner and Wilkin in studying pion-deuteron elastic scattering near the 3-3 resonance with a scintillating target to detect the recoil deuteron. In addition to the measurement of the angular distribution for 256 MeV incident energy, the energy variation of the fixed-angle cross-section (Jlab = 160 deg.) was determined between 141 and 256 MeV. The former was in qualitative agreement with a simple multiple-scattering calculation, but the energy dependence was poorly reproduced. With Gabathuler, he analysed elastic pion-deuteron elastic scattering at medium energies on the basis of the Brueckner model, paying particular attention to the kinematic approximations that have to be made; in contrast to the earlier Glauber-type calculation, the energy dependence of the large-angle cross-section was reasonably well reproduced. Gabathuler, Cox, Domingo, Rohlin, Tanner and Wilkin were joined by E. Pedroni and P. Schwaller in a comparison of p+ and p- total cross-sections of light nuclei near the 3-3 resonance, involving the measurement of the total cross-sections of 4He, 6Li, 7Li, 9Be, 12C and 32S in the energy range 80 - 260 MeV in a transmission experiment; Coulomb corrections were applied using the real parts of the forward nuclear amplitudes, as determined from dispersion relations. At the lower energies there remained large residual differences between the p+ and p- scattering on the isoscalar model, these being largely understandable in terms of the Coulomb distortion. Later the SIN cyclotron was used in a study of charge independence and symmetry from p+ and p- total cross-sections on hydrogen and deuterium near the 3-3 resonance by Pedroni, Gabathuler, Domingo, W. Hirst, Schwaller, J. Arvieux, C. H. Q. Ingram, P. Gretillat, J. Piffaretti, Tanner and Wilkin, the total cross-sections being measured in the energy range 70-370 MeV in a classical transmission experiment using multiwire proportional chambers. The hydrogen data agreed quite well with earlier measurements. After correction for the direct effects of the Coulomb potential, the results showed energy-dependent differences of a few percent between the p+d and p-d cross-sections. This charge symmetry violation could be parametrized in terms of mass and width differences between the D-isobars in agreement with the prediction of the quark model.

Wilkin investigated low-energy pion-nucleon scattering on the basis of the naive a-particle model of the nucleus in three papers, the first with J. Hufner and L. Tauscher, the second and third with J.-F Germond. By using multiple scattering formalisms in the first two papers, the p-nucleus scattering amplitudes were estimated in terms of the p-a ones. It was shown in (i) that at threshold the complex s-wave scattering lengths of the doubly-even nuclei 12C, 16O and 20Ne could be well reproduced using a low-energy scattering theory where the scattering centres in the nucleus were assumed to be fixed and non-overlapping. However only a partial success was obtained in (ii) in describing the p - 12C differential cross-sections in the resonance region, 120-260 MeV, the agreement with experiment being very good at 260 MeV and getting markedly worse with decreasing energy. Hence for further investigation, in (iii), elastic p-40Ca scattering in the region of the first pion-nucleon resonance was calculated within the optical limit of Glauber theory on the basis of the naive model, 40Ca being the heaviest stable nucleus amenable to the simple a-cluster description. When account of the strong short-range repulsion between pairs of a-particles, the predicted cross-sections were quite close to those derived from the conventional nucleon model, though both predictions could be quite accurately parametrised as "fuzzy black discs"!

The anomalies arising from the customary analysis of the experimental data on mesic atoms and meson-nucleus scattering in terms of simple optical potentials led Wilkin to suggest that they might be due to the neglect of the energy dependence of these potentials.

With T. E. O. Ericson he showed that the virtual decay po -> 2g inside a nucleus, and the annihilation reactions p- + p+ -> 2g or e+e- on virtual pions in nuclei (the pionic analogies of positron annihilation in solids) have observable branching ratios. These processes should shed light on the micro-structure of the pion optical potential and on the nuclear pionic field with its coupling and to nucleonic excitation modes; also the e+e- mode would allow the measurement of axial nuclear form factors in contrast to the fixed points of radiative capture.

In a paper on the question whether pion scattering can yield useful nuclear structure information, Wilkin pointed out that for excitations involving magnetic transitions, pion scattering should in principle allow a separation of the orbital and spin contributions whereas this was not possible in electron scattering.

D. S. Butterworth, Germond and Wilkin made estimates of the contributions of different mechanisms to the dependence of the total pion-deuteron cross-section upon the tensor polarization of the target nucleus showing that they all depend sensitively on the deuteron D-state wavefunction. At high energies the multiple scattering seemed to be the most important, the Fermi motion taking over in the resonance region, and meson-exchange current phenomena might be significant above 1 GeV/c.

Germond and Wilkin joined B. S. Aladashvili, V. V. Glagolev, M. S. Nioradze, T. Siemiarczuk, J. Stepaniak, V. N. Streltsov and P. Zielinski in explaining an observed asymmetry in the angle between the proton momentum transfer and the direction of the spectator nucleon in the break-up reaction pd -> ppn at high energies in terms of the strong (np) final-state interaction in the deuteron channel. The separable potential model for the (np) force used in the calculation of this effect also predicted the possibility of significant differences in the distributions of neutron and proton spectators, dependent upon the relative phase of the high energy pp and pn amplitudes. Then the team studied the charge exchange channel of the reaction at 1 GeV in the impulse approximation. The final-state interaction in the 1So state of the pp subsystem induced a slight asymmetry in the spectator proton angle and a threshold enhancement in the pp effective mass. 20% of the observed events, which had large effective mass, could be explained quantitatively by the production of a D resonance, de-excited through a final-state interaction with the spectator nucleon. It was concluded that almost all of the small-angle np charge exchange cross-section at 1 GeV involved nucleon spin-flip.

Brian Martin, also a graduate of Birmingham, came to College in 1962 as a research student of Hamilton, and was given leave of absence to accompany him and complete his work for the London Ph. D. degree at the Niels Bohr Institute, Copenhagen, having been awarded a Ford Foundation Fellowship. A further year at the Institute, as a NATO Fellow, was followed by a two-year Research Associateship at the Brookhaven National Laboratory, USA, and a Lectureship at College in 1968. Membership of Castillejo's group led to a Readership in the 1980-81 session on the basis of an impressive list of publications dealing with the analysis of properties of two-body scattering amplitudes; the use of a wide variety of techniques ranging through phase shift analysis, dispersion relations, finite energy sum rules and duality; work on weak interactions, particularly on kaon decay; his reputation as one of the world experts on the KN system, being responsible for Section 3.2 on KN, KN, pS and pL channels in the 'Compilation of coupling constants and low-energy parameters'; and being a consultant at the Daresbury Nuclear Physics and the Rutherford High Energy Laboratories, as well as advising on the research programme at Copenhagen, where he took leaves of absence from College. He had written a book on Statistics and later collaborated with D. Morgan and G. Shaw on a comprehensive monograph on the pp system.

His first papers recorded in the College Annual Reports were two in 1968. The first concerned an investigation of the dynamics of low-energy, s-wave K+p scattering made by the semi-phenomenological application of dispersion relations. The amplitude in the physical region was taken from current phase-shift analyses of K+p scattering data and the necessary coupling constants for the exchange processes were obtained from experiment, supplemented by the use of SU(3) symmetry when experimental data was not available.The second, with E. de Rafael, involved a phenomenological description of the decays of KL and KS into 2g in the context of CP nonconservation. A discussion of possible measurements having a bearing on the the question of CP non-invariance suggested that the measurement of the time dependence of the asymmetry of intensities between the decays of Ko and Ko into 2g was the most promising. Then with de Rafael, J. Smith and Z. E. S. Uy some implications of nonconservation of CP invariance for the decay of KL into m+m- were discussed with reference to a recent experimental result. In the first of two papers with M. Sakitt on low-energy KN and pion-hyperon interactions, a nine-parameter K-matrix formalism for the low-energy K-p interaction was formulated and the parameters then determined by existing experimental data; in the second paper the parameters were used to obtain scattering lengths and low-energy behaviour of the s-wave KN, pL and pS amplitudes and also, through KN forward-dispersion relation sum rules, to calculate KLN and KSN coupling constants. Collaboration with A. D. Martin and C. G. Ross led to two proposals for the Y*o(1405) resonance, namely (i) as an s-wave virtual bound state of the KN - pSƒ system and (ii) as a CDD pole arising from high-lying channels; comparison with low-energy KN scattering data strongly favoured (i); and collaboration with Y. -A. Chao, R. W. Kraemer and D. W. Thomas in a re-analysis of low-energy KN data, made to investigate the effects of imposing constraints below the elastic threshold, showed that little information about the parameters of the L(1405) could be determined without such constraints.

With G. D. Thompson s- and p-wave K+p scattering below 600 MeV/c were considered, values being obtained for the s-wave scattering length and curvature coefficient by extrapolating the low-energy amplitude to threshold using a parametric form derived from a forward dispersion relation; calculations of p-wave scattering from forward dispersion relation sum rules were made in an iterative manner, starting from the pure s-wave solution of Goldhaber et al. A critical survey of K+p phase-shift analysis, including UCL Spark Chamber Group experimental data, was undertaken with Lea (RHEL) and Thompson, the use of forward dispersion relations to compare solutions being discussed. A quantitative analysis of the remaining solutions was made,and experiments suggested to decide between them. With C. E. Miller a phase-shift analysis of K+p scattering data below 1.3 GeV/c was made using parametrized partial-wave dispersion relations. Examination of the self-consistency of the solutions with backward-angle dispersion relations led to preferred solutions. In a second paper Martin discussed the role of epsilon exchange in KN scattering in relation to the above and calculated the effective e coupling constant. Martin and Miller made an energy dependent phase-shift analysis of 1660 pieces of K+p data below 2 GeV/c to obtain K+p scattering amplitudes, using the parametrized partial-wave dispersion relations, with the additional constraints of forward dispersions and p-wave scattering lengths obtained from forward dispersion sum rules, and then checking the results for consistency with backward K+p dispersion relations.

R. C. E. Devenish published four papers in 1972, the first with J. C. Eilbeck and D. H. Lyth on 'Calculation of the r and D trajectories'; the second with Lyth on 'Single p+ electroproduction at 2 GeV and the pion form factor'; and the third and fourth with Lyth and W. A. Rankin on 'Fixed t dispersion relations and the P11 (1470) resonance in photoproduction' and 'Dispersion relations and the isotenor electromagnetic current in pion photoproduction' respectively. W. S. Lam published three letters in 1972, two with J. Dias de Deus on 'Duality predictions in high energy missing mass spectra' and 'Duality predictions on the ISR data of pp -> pX near the phase boundary' respectively, and the third with Chan Hong-Mo and H. I. Miettinen on 'Factorization and inclusive photoproduction'.

Martin and Devenish fitted pion-nucleon charge exchange data below 2 GeV/c using fixed-t dispersion relations and the hypothesis of two-component duality; predictions for the crossing-even amplitudes were compatible with experiment. The analysis of the p-p data was later updated to include polarization measurements and high-statistics differential cross-sections. Then with Froggatt, they made a simultaneous analysis of low-energy data for the reactions p-p -> KoL and K-p -> poL using the hypothesis of two-component duality combined with fixed t-dispersion relations, results being given for the S*Lp and N*LK couplings. The low-energy amplitudes were used to evaluate FESR integrals and led to large EXD breaking for the K*V - K*T helicity flip amplitudes.

Martin and C. P. Knudsen made a phase-shift analysis, with dispersion relation sum rule constraints, of data to obtain s- and p-wave KN scattering lengths and amplitudes for both I = 0 and 1 in the very low energy region, KL between 0 and 600 MeV/c. With F. Elvekjaer current phase-shift solutions were used to evaluate KN FESR integrals in order to examine zeros and phases of the t-channel exchange amplitudes in the most model-independent-way. K-N partial-wave amplitudes for isospin I=0 and 1 were obtained by Martin from a simultaneous phase-shift analysis analysis of K+p and K+d data in the region below 1.5 GeV/c kaon laboratory momentum. The s-wave I=0 KN scattering length was investigated on the basis of dispersion relation sum rules and evidence from measurements of KN forward differential cross-sections. Then with H. S. Groom, amplitudes corresponding to r and A2 quantum number exchanges in K+-N charge exchange scattering were obtained from data in the few GeV/c region using an analysis based on a fixed-t analyticity in the form of fixed-t dispersion relations and FESR. Martin collaborated with Lea, R. G. Moorhouse and Oades in an energy-dependent multichannel analysis of KN data in the momentum range 0.44 - 1.19 GeV/c using parametrizations based on the K matrix. The amplitude and resonance parameters obtained for the S, P, D and F5/2 waves were compared with those from other analyses.

M. K. Pidcock published two papers in 1974, the first with A. K. Common and D. Hodgkinson on 'The derivative of the popo -> popo g-wave' and the second on 'Crossing sum rules and the popo -> popo g-wave'.

General Physics Group

This group is listed under Massey's leadership in the 1964-65 Departmental Report. A short survey of the miscellaneous researches carried out during his headship of the department is followed by a review of his own and other work during that period in the fields of electron scattering, the resonating group method, and positron physics.

The first publication listed in the 1951-52 College Report is a paper by Bates and Massey on the negative ion concentration in the lower atmosphere. In Massey's work on negative ions and the upper atmosphere, it appeared in his 1937 paper that the removal of negative O ions by associative detachment in the E and F regions must be very slow. However a later examination with Bates, published in 1954, revealed a rapid mechanism, namely, that the O atom and the O- ion approach along an attractive potential energy surface that intersects the final O2 surface and within the crossing a radiationless transition leading to detachment can occur, the lifetime towards this transition possibly being so brief that detachment occurs in almost every collision.

Papers by Buckingham, with Dalgarno, covered the interaction of normal and metastable helium atoms, and the diffusion and excitation transfer of metastable helium in normal gaseous helium; one, with R. A. Scriven, was on diffusion in gaseous helium at low temperatures. Later work on metastable helium included the de-excitation of its atoms in helium (Burhop), its destruction by collision-induced radiation (Burhop & Marriott), and its conversion from the singlet to triplet state by electron collision (Marriott). Marriott and Seaton obtained a simple wave function for He 1s2s1S.

Early work on the continuous absorption by the hydrogen molecular ion by Buckingham, with S. Reid and R. Spence, was followed by a consideration of (i) the detachment of electrons from the ion by impact with neutral atoms (D. W. Sida), (ii) its hyperfine structure (Dalgarno, T. N. L. Patterson & Somerville), and (iii) its continuous absorption coefficient (Somerville). Somerville also published papers on the importance of conservation conditions in distorted wave calculations, the correlation energies of the helium sequence, the effect of coupling to n=3 states on Born 1s-2s and 1s-2p e-H collision cross-section, and cross-sections for e-H collisions in the Born approximation to the reactance matrix.

The discussion of collision processes in meteor trails by Massey and Sida was followed by two papers from Sida, namely, atomic collisions in meteor trails, and the scattering of positive ions by neutral atoms. A consideration of symmetry effects in gas kinetics, in particular, the helium isotopes by Buckingham, with O. Halpern, was followed by molecules with almost spherical symmetry, with C. Carter. Carter carried out work on molecular orbital wave functions for methane and silane, and a theoretical study of pentavalent phosphorus. Earlier M. J. M. Bernal had obtained analytical wave functions for methane and the ammonium ion, and had written on metallic ammonium with Massey.

In connection with the experimental work on atomic hydrogen, quantal scattering theory was applied by Buckingham and Fox to calculate the coefficients of viscosity of the gas from 25 to 300K. Then E. Gal joined them in using a more realistic interaction potential to evaluate the coefficients of viscosity and thermal conductivity from 1 to 400K. Fox and Gal also evaluated the differential and total elastic cross-sections for the collision of unpolarized hydrogen atoms for energies of the relative motion up to 0.37eV; the effect of the identity of the atoms was also considered.

In their work on collisions between atomic systems in the thirties, Massey and Mohr obtained a simple, widely used, formula describing the scattering of atoms by atoms at thermal energies. Some thirty years later Massey with R. B. Bernstein, Dalgarno and Percival applied the formal theory of scattering to the problem of rotational excitation and elastic scattering of homonuclear diatomic molecules by atoms. Earlier K. Takayanagi had considered the rotational transition of the hydrogen molecule by collision.

G. Stephenson published papers on field theory, namely, 'Affine field structure of gravitation and electromagnetism', 'Dirac's electrodynamics and Einstein's unified field theory, some properties of non-symmetric unified field theories' and, with C. W. Kilminster, 'A unified field theory of gravitation' and 'An axiomatic criticism of unified field theories'. P. W. Higgs's consideration of 'Vacuum expectation values as sums over histories', and 'Four-dimensional isobaric spin formalism' was followed by J. G. Gilson on 'Dispersion relation for non-linear vacuum polarization effects'.

In 1952 A. H. de Borde collaborated with G. R. Burbidge on the mesonic Auger effect. Burhop's interest in the Auger effect dated back to his first experimental research work at Melbourne for his M.Sc. degree. His continued interest in the effect led to the publication of his Cambridge Monograph on 'The Auger Effect and Other Radiationless Transitions' in 1952. In 1958 he published a paper on 'The K Auger spectrum', with W. N. Asaad, which extended his work on the theory of the effect to great detail. Later Asaad published his paper on 'Relativistic K electron wave functions by the variational principle.' Burhop also wrote papers on the disintegration of the deuteron by neutron impact, with B. H. Bransden, and on the effect of nuclear size on bremsstrahlung and electron pair production, the former with S. J. Biel. The production of bremsstrahlung in electron-electron collisions, and the radiative corrections to the scattering of electrons and positrons by electrons were considered by M. L. G. Redhead.

Percival published papers on a variational principle for scattering phases; the effect of mutual distortion on phase shifts of a colliding system; the partial wave theory of e-H collisions; the excitation of 3p levels of OI; and waves in a conducting sheet situated in a strong magnetic field. Earlier G. H. A. Cole published a paper on the dynamics of a non-uniform electrically conducting fluid and wrote articles on magnetohydrodynamics and the kinetic theory of monatomic liquids.

In the fifties P. Swan published papers on the elastic scattering of neutrons by tritons at 14MeV; the elastic scattering of neutrons by tritons and of protons by 3He; the existence of a bound state of 4H; and the elastic scattering of electrons by the excited 2s and 3s states of atomic hydrogen. G. A. Erskine calculated the energy per ion pair for -particles in helium. Nuclear disintegrations caused by 50-125 MeV protons and the production of t-mesons were considered by P. E. Hodgson. Then in the early sixties L. F. Abou-Hadid and K. Higgins wrote on the equivalent two-body method for the hypertriton, the former following with a paper on the effect of hard-core and three-body forces on the L-nucleon interaction. E. Leader considered the optical model in p-nuclear scattering and, with A. C. Hearn, fixed-angle dispersion relations for nucleon Compton scattering.

Turning to the Massey post-1950 researches on electron scattering, the following survey is along the lines of that in the B.B.D. biographical memoir, namely, through the application of variational methods. With atomic hydrogen as the target, he and B. L. Moiseiwitsch thoroughly studied the effects of exchange and polarization on elastic scattering; with G. A. Erskine he calculated the cross-section for the excitation of the 2s state by means of the distorted wave method, making full allowance for exchange; and with S. Khashaba he did the corresponding, more complicated, calculations for the 2p state, obtaining the polarization of the impact radiation as given by the different approximations - Born, distorted wave, Born-Oppenheimer, and exchange-distorted wave. A similar programme was followed on helium, Moiseiwitsch, at Massey's suggestion, investigating elastic scattering, and then the two of them combining to calculate the cross-sections for the excitation of the 21S and 23S terms, and for the excitation of the 23P term. The 23S calculations were the first to give a sharp resonance peak just above threshold. Massey's two pioneering calculations, the second with Mohr, on elastic scattering of electrons by molecular hydrogen in the early thirties were unsuccessful in the energy region below 100eV. However quite good agreement with experiment was achieved in the mid-fifties by exploiting the power of variational methods with R. O. Ridley.

Bates in the biographical memoir records Massey's feeling that his work with the resonating group method was rather underrated. This led him to invite Phil Burke, who was a member of the UCL research team involved, to contribute the perceptive account of Massey's work included in the memoir. Burke begins by explaining that the method, proposed in two 1937 papers by J. A. Wheeler, was based on the idea that nucleons in nuclei spend fractions of their time resonating between various substructures or groups and, after discussing the general theory, considered the scattering of neutrons by deuterons and the binding energy of the triton. In the forties and fifties the method was extensively and almost exclusively developed and applied by the Massey group to study the problem of scattering involving few nucleons. The first paper by Massey and Buckingham in 1941 studied the scattering of neutrons by deuterons; the problem was formulated for various types of nuclear forces, and the resultant integro-differential equation solved for s- and p-wave scattering with the help of Drs. L. J. Comrie and H. O. Hartley of the Scientific Computimg Service, the work being one of the first and certainly the most detailed attempt to identify the nature of nuclear forces from the scattering of light nuclei. In the early fifties the work on n-d scattering was extended by Massey, Buckingham and S. J. Hubbard and by Massey and de Borde by the inclusion of higher partial waves and calculations to higher energies. Later Burke and H. H. Robertson, at Massey's suggestion extended the calculation to a wider range of nuclear forces; Bransden, K. Smith and C. Tate included tensor forces in the theory; and Burke and F. A. Hass allowed for the polarization of the deuteron during the collision. Massey reviewed the status of the work on the nuclear three-body problem at an International Conference on Nuclear Forces and the Few-Nucleom Problem held at College from 8-11 July 1959.

During the fifties several other few-nucleon systems were studied by the resonating group method. These included n-a scattering, determination of the spin-orbit interaction (Massey, S. Hochberg, Robertson & L. H. Underhill) and contribution of tensor forces (A. Sugie, Hodgson & Robertson); elastic scattering of neutrons by tritons and 3He (Bransden, Robertson & Swan) and theory of neutron-triton scattering (Hochberg, D. J. Newman & Robertson); deuteron-triton scattering, two channel, five nucleon reactions with central forces (W. Lasker, Tate B, Pardoe & Burke); and the binding energy of 8Be and 12C and a-a scattering (S. J. Biel, A. C. Butcher & J. M. McNamee). Much of the work was done on the pilot ACE and DEUCE computers at the National Physical Laboratory, Teddington with the collaboration of Robertson, who had written a general programme to solve the integro-differential equations by a linear algebraic method. Massey arranged for most of his students to spend periods varying from a few days to several months working at NPL with Robertson, most of the early aforesaid calculations being completed in this way. In 1958-59 the method was reprogrammed for the Feranti Mercury Computer at the University Computer Unit where Buckingham had become Director. In view of the computational difficulties only light systems could be studied with restricted approximate nucleon-nucleon interactions, nearly always an effective central force being used to represent on average the exact interaction, which involved spin-orbit and tensor components. Nevertheless results were obtained in fairly general agreement with experiment.

In the sixties work continued with most emphasis on n-d scattering. At Massey's suggestion J. W. Humberston carried out a series of calculations, the first on elastic scattering using rather simple spin and iso-spin dependent potentials. Distortion of the target deuteron was ignored at first, but later an elaborate variational calculation was done using a very flexible trial function incorporating terms representing all possible forms of distortion, and the first fully converged results for n-d s-wave phase shifts and scattering lengths were obtained. Distortion was found to be very important in the doublet spin state, but the discrepancy between the theoretical and experimental results indicated that no purely central potential was compatible with the three-nucleon data. It was therefore necessary to use potentials with central, tensor and spin-orbit components. In 1965 the Hamada-Johnson potential was the most accurate such potential and it was used in an elaborate calculation of the binding energy of the triton. Again an essentially fully convergent result was obtained, but the result (-6.3MeV) differed from the experimental value (-8.5MeV). At first the discrepancy was regarded as evidence for the existence of three-body forces; however the results were found to depend rather sensitively on some of the parameters in the potential and it would have been necessary to determine these parameters to a higher precision to establish the existence of such forces. Colleagues involved with Humberston in the triton binding energy work were S. M. Hawkins, M. A. Hennell & J. B. Wallace. In addition to the aforesaid work with realistic nucleon-nucleon potentials, Humberston (with R. L. Hall & T. A. Osborn) investigated various features of the three-body system using rather simple model potentials.

Massey read a paper (Can. J. Phys. 60, 461-470) on 'Gaseous positronics - past, present, and future' at the International Conference on positron collisions in gases held at York University, Toronto in 1981. He recalled that 1981 was 50 years from the time midway between the first observations of positrons in cosmic radiation and their theoretical prediction. Being at Cambridge carrying out both experimental and theoretical research (Rutherford always insisted that the lab should be closed between 6 pm and 9 am), he remembered "hearing about Dirac's ideas of the vacuum populated by electrons occupying all the available free particle states of negative energy, and arousing much interest that same evening at a meeting of the Junior Physical Club by describing Dirac's latest wizardry". He had been fascinated with Dirac's wave equation from his M. Sc. days in Melbourne, recalling "being sharply reprimanded by the Senior Demonstrator when I overtly studied Dirac's paper in the Proceedings of the Royal Society (A) while supposedly demonstrating to a practical class." His first scientific paper to be published was a calculation of the effect of a nuclear magnetic moment on the scattering of fast electrons using the Dirac equation. His first paper on positrons was concerned with their collisions at relativistic energies, namely, the calculation of the rate of radiationless annihilation of positrons in collisions with atoms with Burhop. Then he contrasted the scattering of positrons at relativistic energies with that of electrons at the same energies. The beginning of the experimental study of slow positrons in gases at the time of his transfer to the Quain chair of physics led to his special interest in positron physics. As mentioned on p. 112 there followed the collaboration with Mohr in a preliminary survey of the collision processes of positrons and positronium in gases, that with Moussa on positronium formation in helium, Fraser's calculations on positronium collisions in hydrogen and helium, and the establishment of the experimental positron physics group. Massey recalled a meeting with Ramsauer in West Berlin, when the latter remarked how interesting it would be if experiments were carried out with slow positrons in gases as with electrons to obtain total cross-sections as a function of energy. Massey replied that since the static field of an atom is repulsive for positrons, there would be no Ramsauer effect. In the mid-sixties he carried out schematic calculations with I. H. Sloan, W. J. Cody, J. Lawson & K. Smith to see what sort of variation of cross-section with velocity might be expected for positrons when polarization was taken into account. The results showed that it would not be surprising to find Ramsauer effects in the scattering. He was particularly gratified that the first systematic measurements of total cross-sections for scattering by positrons were made in the department in the early seventies. In the early seventies he published two papers on the behaviour of positrons in molecular gases, the first with Lawson and S. Hara on the dependence of their annihilation rates in rare gases on the presence of molecules, and the second with Hara on their annihilation in Ar-CO mixtures.

By 1970 Humberston's work on n-d scattering was ending and he became interested in collision problems associated with slow positrons in gases, and was able to apply his experience to carry out elaborate variational calculations to the relatively simple problems of positron elastic scattering. As an introduction to the field, he carried out with J. B. G. Wallace a detailed study of positron scattering by hydrogen atoms which yielded the first accurate results for the positron annihilation rate and the angular correlation of the g-rays. The results proved particularly interesting in helping to explain some features of the electron-positron annihilation radiation coming from the direction of the galactic centre. There followed the more complicated problem of positron scattering by helium atoms, definitive values of elastic scattering phase shifts and annihilation parameters being obtained for several partial waves. The resulting cross-sections were in excellent agreement with the most accurate experimental values, and were used to resolve a discrepancy between various experimental results. The values of the scattering and annihilation parameters were used in a detailed study of the lifetime spectrum of positrons diffusing in helium gas, excellent agreement being obtained with the most accurate experimental spectra. R. I. Campeau collaborated with Humberston in some of the work.

Turning his attention to positronium formation in positron-atom collisions, he calculated the s- and p-wave contributions in hydrogen. By examining the variation of the results with respect to systematic improvements in the trial function it was established that the results were essentially fully converged. C. J. Brown then collaborated with him in the calculation of the d-wave contribution, the combined results being the most accurate then available. Finally mention is made of the collaboration of M. S. T. Watts with Humberston to investigate low-energy positron-lithium scattering in the energy region below the first excitation threshold so that only elastic scattering and positronium formation needed to be considered.

CUSC (Computers in the Undergraduate Science Curriculum)

In 1973 the government established a 5-year National Development programme in Computer Assisted Learning (CAL) charged with stimulating CAL at all levels of education. A small group of scientific staff from UCL, Chelsea College and University of Surrey involved in CAL submitted a proposal to the National Development Programme for a substantial development project to use interactive graphical displays; this was accepted, and CUSC started officially in January 1974. Later Queen Elizabeth College joined the collaboration.

The original UCL staff involved, Castillejo and McKenzie, were joined by Humberston in the Autumn of 1973 on his return from a sabbatical in USA. McKenzie developed a PDP 11/34 computer to aid learning and teaching; a set of conversational programmes was used in the first-year laboratory to enable students to introduce themselves to computer programming in BASIC. He then developed two teaching packages, Phasors and Multiphasors, and used them in his first-year course on Waves, Optics and Acoustics. In the first, the amplitudes of two waves and the phase difference between them are chosen by the student; at any time he may change the phase difference, observe the wave sum, the phasor diagrams of the separate waves or their sum, and a plot of Intensity against phase difference for the waves. In the second, the number of waves and the increment of phase difference between them are specified by the student; the screen displays the phasor diagram for any phase difference, and upon request, a plot of Intensity against phase difference.

Two teaching packages, namely Schrödinger Bound State and Positive Energy respectively, were developed by Humberston and used extensively in his second-year quantum mechanics course to illustrate various basic ideas in quantum mechanics. In the first the student defines the width and depth of a square well, the particle mass and energy, and the function parity, and then views the corresponding curve of the wave function. In the second the student defines the potential barrier width and height, the particle mass and energy, and then views the wave functions for the incident, reflected, and transmitted waves; the real and imaginary parts may be shown separately; the transmission coefficient is listed and the probability density may also be displayed.

McKenzie became Project Director of the CUSC project in 1974; he is joint Editor (with L.R.B. Elton of Surrey and R. Lewis of Chelsea) of 'Interactive Computer Graphics in Science Teaching', a book first published in 1978 by Ellis Horwood Ltd., Chichester. The book records the development of the 4-year project, covering technical matters of computers, graphical terminals etc., and lists some 40 teaching packages developed for physics, chemistry, and biology students.

Review of other Departmental Affairs


In Massey's first session the undergraduate courses continued to be:
Intermediate - E1 Mathematical Group and E2 Biological Group;
General Degree - First-year, G 1, and Second Year, G 2;
Ancillary - First-year, A 1, and Second-year, A 2;
Special Degree - First, Second and Third-year, S 1, S 2 and S 3.

Members of staff accompanying Massey into the department, immediately became involved in the teaching of some of these courses, as the following lecture programme shows:
E1(Mathematical) and E2 (Biological) - Burhop, Fox and Jennings.
G1 and A1 (combined) - Heat, Fox; Optics, Griffith; Electricity & Magnetism, Heyland; Properties of Matter, and Sound, Burhop; G1 - Thermodynamics, Fox; A1 - Kinetic Theory, Henderson.
G2 and A2 (combined) - Optics, Griffith; Electricity & Magnetism, Electronics, Heymann; Sound, Burhop; Modern physics, Jennings; Gravitation, Kinetic Theory, Henderson.
S1 - Heat & Thermodynamics, Wood; S1 - Electricity & Magnetism, Duncanson and Heyland; Properties of Matter, combined with G1 and A1.
S2 - Heat and Thermodynamics, combined with S1, Properties of Matter and Sound, R. C. Brown; Modern Physics, Gibbs and G. B. Brown.
S3 - course was completely revised, an alternative Part II option on Mathematical Physics being introduced. Massey gave three lectures per week on Modern Physics throughout the session to all students. Boyd, Dodd and Hasted each gave one lecture per week on Selected Topics in Experimental Physics to students taking the Experimental Physics option, and Buckingham, Castillejo and Seaton gave a corresponding series in Mathematical Physics to those taking the new option. The six-hour Part II practical examination involved plotting curves showing how the rate of exhaustion of air from a Winchester flask by a water pump depended upon the rate of flow of water through the pump and on the pressure in the flask. The corresponding theoretical problem paper consisted of two questions, both to be answered. The first tabulated the variation of internal energy of a symmetrical diatomic molecule with internuclear distance and required the position and depth of the minimum energy to be determined and thence the best values of the coefficients in an approximate representation of the internal energy. Given an approximate formula for the vibrational and rotational energy levels of the molecule, an estimate was required of (a) the percentage of molecules occupying those levels in a gas at 2000K; (b) the variation of molar specific heat of the gas between 1000K and 6000K, assuming the reduced mass of one molecule to be equal to one proton. In the second question the number of disintegrations occurring in a small sample of radioactive material over successive periods of one day were tabulated for ten days. On the basis of the process being suspected of involving two successive disintegrations, it was required to estimate the half-life of the parent substance and of the intermediate product.

Postgraduate courses were introduced, namely, Bates on 'Atomic Collisions'; Seaton on 'Atomic and Molecular Structure'; Burhop on 'Nuclear Physics'; Castillejo on 'Field Theories'; and Massey on 'Relativistic Quantum Mechanics and Field Theory'.

Wood gave the Optics course to the combined S1 and S2 classes in the 1951-52 session, retiring at the end of the session. His formal retirement at the end of the session led to a change in the S-lecture programme namely, Heat & Thermodynamics and Optics being spread over two sessions, Fox starting with Heat & Thermodynamics to S1 in the 1951-52 session and completing the course with S2 in the following session, as Jennings started the corresponding cycle with the new S1 class; R. C. Brown and Dodd gave the corresponding Optics cycles starting with the S1 classes in the 1952-53 and 1953-54 sessions respectively. R. C. Brown's place in the Properties of Matter cycle with Henderson was taken over by G. B. Brown, Boyd replacing the latter with Gibbs on the S2 Modern Physics course; and Duncanson (then Burhop) and Heyland continued with the Electricity & Magnetism cycle.

A S1 problem class was introduced in the 1951-52 session being taken by Fox and Jennings, and the S2 Ancillary Mathematics course was taken over by Seaton in the 1952-53. As mentioned on p.52 Wood continued lecturing after his retirement, taking the three mid-day Intermediate lectures until the course was disbanded at the end of the 1956-57 session. The General degree course was also disbanded at the end of this session, leaving the department with one-year Ancillary courses for Biochemistry, Physiology, and Statistics students, and two-year Ancillary courses for Astronomy, Chemistry and Geology students.

As mentioned on p. 63 the department rather reluctantly introduced the College-based-course degree structure in 1966. (Earlier Massey had written to Gibbs expressing his alarm at which the proposals for the new degree structure were being rushed through and asked for this to be raised at the Board of Studies in Physics with the view to presentation at higher level in the University.) To appreciate the structure of the course units and syllabuses adopted, the following reference is made to the pre-1966 scheme, i.e., the University B. Sc. special degree in physics. To qualify for this degree, an undergraduate had to satisfy the examiners in (i) the ancillary examination in mathematics, normally taken at the end of the first year; (ii) the examination in mathematical methods in physics, normally taken at the beginning of the third term of the second year; (ii) part I of the final examination in physics, normally taken at the end of the second year; (iv) part II of the final examination, normally taken at the end of the third year. A new syllabus for part I came into operation in 1963, the main headings of of the five papers being as follows:
Paper I - Newtonian Mechanics; Special Relativity; Continuous Media: Vibrations and Waves in Mechanical Systems; Kinetic Theory.
Paper II - Heat and Thermodynamics: Structure of Matter; Irreversible Processes.
Paper III - Fields; Circuits and Techniques; Magnetism; Electrons in Solids; Conduction of Gases.
Paper IV - General Properties of Waves; Electromagnetic Radiation; Electromagnetic Spectrum; Interference; Diffraction; Interaction with Matter; Geometric Optics.
Paper V - Elementary Particles; Atomic Physics; Nuclear Physics.
These theory papers were set and marked by appropriate committees of the University Board of Examiners in Physics.

From 1965 only one six-hour examination in practical physics was held in Part I, this involving at UCL a common experiment of the problem type; the examination involving an experiment of the routine type being abolished, more weight was given to the normal laboratory course work in experimental physics.

For the Schools of the University Part II was an internal examination and at UCL three theory papers were set and marked by UCL staff. There were experimental and mathematical physics options. The common syllabus consisted of quantum mechanics, atomic physics, nuclear physics, elementary particle physics, statistical mechanics, solid state physics, and some special topics such as superfluidity and superconductivity. Students taking the experimental option had additional lectures on statistical methods and advanced electronics; they attended courses in Engineering Drawing, Workshop Practice and Experimental Radioactivity; and they undertook a major experimental project and presented a report thereon. Students taking the mathematical physics option attended a course of lectures on classical mechanics, electrodynamics, advanced mathematical methods, numerical analysis and computing; and each student was allotted a problem in Mathematical Physics of the research type and presented a dissertation on it.

Courses introduced in place of previous Ancillary courses were:
B101 Basic Physics for Biological sciences (1 c.u.)
B102 Basic Physics for Chemistry (1 c.u.).
B104 Physics for Astronomy (1 c.u.).
B201 Physics for Biological sciences (1/2 c.u.).
B202 Electricity and Magnetism (1/2 c.u.).
B203 Physical Measurements (1/2 c.u.).
B204 Physics for Astronomy (1 c.u.).

University regulations required that during the three-year course a student must complete a minimum of 9 course units and pass the examinations associated with at least 8 of them in order to obtain a degree.

As explained below, first-year physics students started in the 1966-67 session the following 11 course-units scheme, second and third-year students carrying on with the lectures under the B.Sc. special degree system.

 First Year  Second Year  Third Year
 B11 General Physics  B21 Bulk Properties of Matter II  C31 Theoretical Physics
 B12 Bulk Properties of Matter I  B22 Light & Electro-magnetism II  C32 Solid State Physics
 B13 Light & Electro-magnetism I  B23 Atomic & Nuclear Physics  C33 Atomic, Nuclear & High Energy Physics
 B1 Pure & Applied Mathematics  B4 Mathematical Methods in Physics  

The nine Physics courses were approved by the Board of Studies in Physics, the two Mathematics courses by the Board of Studies in Mathematics.

The main headings of the physics courses were:
B11 - Historical Introduction and Survey of Modern Physics; Vibrations and Waves; Classical Mechanics; Special Theory of Relativity.
B12 - Heat and Thermodynamics; Introductory Statistical Mechanics; Kinetic Theory of Gases.
B13 - Geometrical Optics; Interference; Diffraction; Polarization; Electrostatics; Steady Currents; Magnetic Effects of Currents; A. C. Circuit Theory; Electromechanical Devices.
B21 - Mechanics; Relativity; Sound and Ultrasonics; Geophysics; Thermodynamics.
B22 - Light; Electricity and Magnetism; Electromagnetic Waves; Electronics.
B23 - Quantum Theory; Atomic Physics; Nuclear Physics; Solid State Physics.
C31 - Mathematics; Quantum Mechanics; Astrophysics.
C32 - Statistical Mechanics; Solid State and Metal Physics; Superfluidity and Superconductivity; Electronics.
C33 - Atomic Physics; Nuclear Physics; b-radioactivity; Elementary Particle Physics.

The Physics Sub-Board of Examiners in Physics was required to submit a scheme for the award of Honours to the College Board for approval on the basis of relative weights of 1:2:3 for first, second, and third-year work. It decided that B1 and B4 should count equally with the three first and three second-year physics courses respectively; that it would work on the basis of percentage marks rather than on grades 1-9, favoured by the Biological Science departments which operated a common scheme for honours, namely, grades 1-9, divided into groups of three, classed A, B, and C respectively. To comply with Faculty requirements it established an equivalent percentage mark-grade band corresponding to the classifications A, B, C, and F given to students for course-unit examinations. The scheme for the award of Honours was based on that used for the B.Sc. special degree.

In September 1968 a new third-year course C30 on Physics of Solids was introduced to form the ninth course-unit for six students who had failed two or more B course-units, they forming a class equivalent to the old B. Sc. pass degree class.

The new course structure was devised and the individual course units planned on the basis of the general principles (i) the course should continue to be of a special nature, directed towards the dedicated student of physics who aimed to become a professional physicist, (ii) emphasis should be on those branches of the subject necessary for an appreciation of the main points of growth of contemporary physics, (iii) since the requisite background knowledge of basic physics was sufficiently comprehensive and detailed to constitute a full three years' study, leaving no time for optional courses, a common course structure should be followed by all undergraduates, (iv) the separate course units should be designed to reveal the unity of the subject and where possible to allow an increasing depth of treatment to be followed year by year. Hence the third-year experimental and mathematical physics of the B.Sc. degree were abolished and a common lecture course was adopted with the recognition that a special aptitude for mathematical physics or a particular inability in experimental physics could be met in the choice of the third-year project.

A syllabus revision committee was appointed, consisting of Massey, Burhop, Castillejo, Heymann, Seaton and Fox, to devise a coherent course unit system within the foregoing framework. It sought not only the views of departmental staff, but also those of other physics departments, e.g., a newly, and an old, established department, Sussex and Manchester respectively. In arranging the first-year course units, the needs of 'freshers' were particularly borne in mind, B11 being designed to encourage and stimulate enthusiasm for physics at university level, particular care being paid to its teaching, even though parts of B12 and B13 might appear less interesting. Prof. Massey instituted regular meetings with students to obtain first-hand information of their experiences of the new courses and in 1967 a staff meeting was held to review the year's experience.

In parallel with the syllabus committee, a sub-committee was appointed, consisting of Fox, Heyland, Bullock, Lush, M. J. B. Duff and Metheringham, to consider the experimental programme. In the B.Sc. special degree course, first and second-year students spent three afternoons per week in the laboratories and wrote accounts of each experiment performed, handing in a practical note-book for marking each week. It was decided to abolish the old Part I practical examination and to introduce complete continuous assessment represented by a course mark assigned to each Physics course-unit studied. Students were required to spend only two afternoons per week in the laboratories during their first and second years and present detailed accounts of only about six experiments performed, half of which were chosen by themselves. The first and second-year experiments were designed to illustrate physical principles and theories, to teach specific techniques, and to provide an integrated training in the essentials of experimental physics. Some experiments were open-ended and some were project-typed, designed to give scope for creativity in the context of experimental physics. Some specialised short courses were retained, e.g. workshop practice, technical drawing and radioactivity, and new courses in electronics and computing were introduced. The third-year major project was retained since this offered greatest scope for initiative and creativity, and had proved to be highly successful in stimulating interest and developing critical thought and attitudes; again credit for the project was allocated to each C course-unit.

A new third-year scheme was introduced for the 1969-70 session, under which there were two common courses and one optional course, the latter reflecting student opinion. The common courses were:
C34 - Quantum Mechanics, Atomic Physics, Solid State Physics.
C35 - Nuclear Physics, Elementary Particle Physics, Mathematics.

The optional course was chosen from:
C36 - Astrophysics and Geophysics.
C37 - Plasma Physics, Materials Science, Superfluidity and Superconductivity.

As mentioned on p. 68, the swing away from the physical sciences among candidates seeking admission to the universities hit the department badly in physics, and led to the introduction of two new degree courses. Following discussions with several members of the Departments of Chemistry and Physics with Professors Nyholm and Massey a working party, consisting of Professors Millen and Tobe with Professor Willmore and B. G. Duff, explored the possibility of chemistry/physics or other interdisciplinary degree courses. Consequently a new joint Chemistry/Physics degree course, intended for a small number of high-grade students and offering the choice of transfer to chemistry or physics at the end of the first year, was introduced in the 1969-70 session, with the admission of 8 students.. This required the introduction of two new half course-units of physics, namely, B13(a) - Electromagnetism and B205 - Solid State Physics, specifically for the joint-degree students. The degree structure was:

 First Year  Second Year  Third Year
 B1, B11, B13(a), and
 11/2 c.u. of Chemistry
 B4, B23, B205 and
 11/2 c.u. of Chemistry
 3 c.u. and a project, subject to a
 minimum of 1 c.u. of Phys/Chem.

An Applied Physics Committee, consisting of Willmore, D. G. Davis, M. J. B. Duff and M. J. Esten explored the possibility of an applied physics degree course, with the result of the admission in the 1970-71 session of 7 students to the newly instituted Applied Physics degree course. Only two additional third-year course-units were introduced, namely, C38 - Systems, Computers and Control, and C39 - Microwaves and Modern Optics, a joint c.u. with the Department of Electronic and Electrical Engineering. The degree structure only differed from that for the Physics degree in the third year, namely:

 First Year  Second Year  Third Year
 B1, B11, B12, B13  B4, B21, B22, B23  C38, C39 and 1 c.u.
 from the other four

A change in the Physics degree structure was made in the third-year courses, namely, C34, C35 and 1 c.u. chosen from C36, C37, C38 and C39.

The B.Sc. (Special) degree in Astronomy included observational and practical work carried out at the Observatory at Mill Hill. In addition to Astronomy, the course included a one-year ancillary course in Mathematics and a two-year ancillary course in Physics. The examinations in ancillary Mathematics and ancillary Physics were taken at the ends of the first and second sessions respectively. Part I of the final examination in Astronomy was taken normally at the end of the second session, and Part II at the end of the third session. Students were required to pass the normal test on the translation into English of scientific texts in two languages. Astronomy lectures were given, e.g., as follows:

First Year - S1 (Part 1)
S1-1 Descriptive astronomy: Monday at 10; Wednesday at 12.
S1-2 Spherical astronomy: Wednesday at 10; Friday at 12.
S1-3e Observational astronomy; Thursday at 6.

Second Year - S2 (Part 1)
S2-1 Astrophysics, (50 lectures).
S2-2 Dynamics.
S2-3 Spherical astronomy, (20 lectures).

Third Year - S3 (Part 2)
Three courses, of 40 lectures each, selected by arrangement from:
 Stellar structure Galactic structure
 Astronomical spectroscopy Radio astronomy
 Stellar atmospheres Solar physics
 Celestial mechanics Mathematical astrophysics
 Statistical astronomy

The Observatory was open for practical work on Tuesday and Thursday from 2 to 10 p.m. First-year students attended practical classes on Thursdays, and second and third-year students attended on Tuesdays and Thursdays.

The Astronomy Department courses listed for the new B. Sc. degree were:

B1 Astronomy (11/2 c.u.)
B2 Astrophysics (11/2 c.u.)
B3 Orbital astronomy (1/2 c.u.)
B4 Stellar astronomy (1/2 c.u.)
C1 Observational astronomy (1 c.u.)
C2 Stellar interiors and atmospheres (1 c.u.)
C3 Solar and radio astronomy (1 c.u.)
C4 Stellar and galactic systems (1 c.u.)
C5 Statistical astronomy (1/2 c.u.)
C6 Lunar and planetary astronomy (1/2 c.u.)
These courses were approved by the University Special Advisory Committee in Astronomy.

The 1974-75 session was historic for several reasons, the most significant being it was the last of the Massey regime. The first entry to a joint Astronomy-Physics B.Sc. degree and the introduction of half-course units took place in October 1974. Massey started his last series of lectures, giving the 1/2 c.u. on Modern Physics and Astronomy to the Physics, Astronomy and joint Astronomy and Physics students, and Wilson started his first series, giving the 1/2 c.u. on Foundations of Modern Astronomy to the Astronomy and joint Astronomy and Physics students. As reported on p. 70, the flexibility of the half-units reducing the work-load of some students and enabling the less able student to select less demanding courses, but not retarding the most able, produced an immediate reduction in the drop-out rate of the first-year students. These half-units arose from a comprehensive review of the existing courses by a syllabus re-organization committee, proposed courses being examined by small groups of teachers suggesting tentative lists of topics to be included each course; the committee then ensured the coherence of topics in each course. The applied physics third-year courses resulted from the committee's discussions with the Department of Electronic and Electrical Engineering. A half-unit course normally consisted of c. 35 lectures and c. 5 separately time-tabled discussion periods, the latter enabling revision of difficult topics, attention to specific problems that had arisen, and generally to monitor the progress of the course.

The structures of the five degree courses offered by the department were listed in the 1974 departmental booklet as follows:

Physics and Applied Physics Degree Courses

First Year
1 c.u. Practical physics, including courses in workshop practice, engineering design and drawing, statistics, and computer programming in FORTRAN language.
1/2 c.u. Electricity and magnetism.
1/2 c.u. Modern physics and astronomy.
1/2 c.u. Thermodynamics, kinetic theory and radiation.
1/2 c.u. Waves, optics and acoustics.
1/2 c.u. Mathematics in physics.
1/2 c.u. Pure mathematics or Supplementary mathematics.

Second Year
1 c.u. Practical physics, including lectures on electronics with associated laboratory work.
1/2 c.u. Electromagnetic theory.
1/2 c.u. Quantum physics.
1/2 c.u. Mathematical methods in physics I. PLUS
Three half-unit courses chosen from the options:
Atomic and nuclear physics.
Earth resources.
Mathematical methods in physics II.
Modern acoustics and fluid mechanics (recommended for Applied Physics students).
Physics of solids and statistical mechanics.

Third Year
1 c.u. Project
Six optional half-unit courses chosen from:
Physics students chose the majority of their options from the Physics list including;
Atomic and molecular physics; Extreme states of matter; Methods of mathematical physics; Nuclear
and particle physics; Plasma physics; Quantum theory; Solid state physics.

Applied Physics students chose the majority of their options from a list including;
Computer hardware; Computer software and systems; Control theory and machine intelligence;
Microwaves; Modern optics; Project management.

Both Physics and Applied Physics students could also choose options from the Astronomy list.

Astronomy Degree Course
First Year
1/2 c.u. Practical physics, including courses in workshop practice, engineering design and drawing, statics and computer programming in FORTRAN language.
1/2 c.u. Practical astronomy.
1/2 c.u. Basic astronomy.
1/2 c.u. Modern physics and astronomy.
.1/2 c.u. Physics.
1/2 c.u. Mathematical astronomy.
1/2 c.u. Mathematics for physics.
1/2 c.u. Pure mathematics or Supplementary mathematics.

Second Year
1 c.u. Practical astrophysics, including lectures on electronics with associated laboratory work.
1/2 c.u. Astronomical techniques.
1/2 c.u. Astrophysics and atomic physics.
1/2 c.u. Astrophysics and radiation.
1/2 c.u. Astrophysics and properties of gases.
Two half-unit courses chosen from the options;
Mathematical methods in physics I; Mathematical methods in physics II; Earth resources or another physics option; Introduction to geology.

Third Year
1 c.u. Project.
1/2 c.u. Observational astronomy.
Five optional half-unit courses chosen from the Astronomy list:
Cosmic abundances of the elements; Extra-galactic astronomy; Geophysics; High-energy astrophysics; Interstellar physics; Lunar geology; Planetary astronomy; Solar physics; Stellar atmospheres; Stellar structure and evolution; Relativity and cosmology.
Options could also be chosen from the Physics or Applied Physics list.

Astronomy and Physics Degree Course
First Year
1/2 c.u. Practical physics, including courses in workshop practice, engineering design and drawing, statistics and computer programming in FORTRAN language.
1/2 c.u. Basic astronomy.
1/2 c.u. Modern physics and astronomy.
1/2 c.u. Electricity and magnetism.
1/2 c.u. Waves, optics and acoustics.
1/2 c.u. Mathematics for physics.
1/2 c.u. Practical astronomy or practical physics.
1/2 c.u. Pure mathematics or Supplementary mathematics.

Second Year
1 c.u. Practical astrophysics, including lectures on electronics with associated laboratory work.
1/2 c.u. Astrophysics and atomic physics.
1/2 c.u. Astrophysics and radiation.
1/2 c.u. Astrophysics and properties of gases.
1/2 c.u. Quantum and solid state physics.
1/2 c.u. Mathematical methods in physics I.
One half-unit course chosen from:
Astronomical techniques; Earth resources; Mathematical methods in physics II; Modern acoustics and fluid dynamics.

Third Year
1 c.u. Project.
Six half-unit courses chosen from the three third-year lists of options subject to a minimum of two in
Astronomy and two in Physics or Applied Physics.

Chemistry and Physics Degree Course
First Year
1/2 c.u. Chemistry of atoms and molecules.
1/2 c.u. Physical chemistry, including practical work.
1/2 c.u. Chemical physics.
1/2 c.u. Practical physics, including courses in engineering design and drawing, statistics, and computer programming in FORTRAN language.
1/2 c.u. Electricity and magnetism.
1/2 c.u. Waves, optics and acoustics.
1/2 c.u. Mathematics for physics.
1/2 c.u. Pure mathematics or Supplementary mathematics

Second Year
1 c.u. Physical Chemistry.
1/2 c.u. Practical physics, including lectures on electronics with associated laboratory work.
1/2 c.u. Atomic and nuclear physics.
1/2 c.u. Electromagnetic theory.
1/2 c.u. Chemical physics.
1/2 c.u. Mathematical methods in physics.
1/2 c.u. Pure mathematics or any other available Chemistry or Physics option.

Third Year
1 c.u. Project in Chemistry or Physics.
Six half-unit courses chosen from any of the third-year options offered by the two Departments, subject to a minimum of two in Chemistry and two in Physics or Applied Physics.

It was possible to transfer from a joint honours course to one of the associated single subject courses at the end of the first year, without loss of time or credit; a similar transfer from Physics to Applied Physics or vice versa could be made at the end of the first or second year.

The statistics component of the first-year practical physics course embraced the statistical analysis of experimental data and FORTRAN programming using the College IBM 360/65 computer. In the first year, Physics students started project work in the summer term, e.g., construction of magnetometers of the type used in spacecraft. A more extensive six-weeks project was undertaken in the second year, e.g., Schlieren photography in a wind tunnel. The Physics third-year major project could be be experimental or theoretical, a wide range of topics being available e.g., development of x-ray, ultra-violet and infra-red detectors, study of traffic control problems by computer techniques, investigations using molecular and positron beams, analysis of winds on Mars, and a theoretical study of pulsars. Besides the third-year project, the Astronomy students had an advanced course in observational astronomy, the main telescopes used by them at the Observatory being the 24-inch Radcliffe refractor and a modern 24-inch reflector.

In the 1975-76 session lectures for first and second-year students changed from the term to the semester system then introduced in the Faculty of Science.


Some academic tutorials were introduced in the 1954-55 session, a systematic system following later with all students attending a weekly tutorial for one hour. Pairs of first and second-year students were tutored by a member of the teaching staff and on alternate weeks took their "problem" books, which had been marked by their tutor, for discussion of any outstanding points; later these students met in groups of four. Third-year students met in groups of two, with specially chosen postgraduate students as tutors. The introduction of the course-unit degree system led to a cyclic arrangement of tutorials for first-year students, namely, four sets of students, each consisting of three sub-sets, the twelve sub-sets moving cyclically each week amongst the three tutors assigned to each set; however this was abandoned in 1969. Third-year optional course-units led to a weekly cyclical movements of tutorial sub-sets amongst tutors assigned to specific course-units.

A Departmental Tutor was not appointed until 1964, when Dodd took on the post. Duties of departmental tutors, as approved by the College Committee on 6 July 1965 and amended in the light of subsequent developments, were classified as Academic and Pastoral, the former consisting of Admissions, Progress and Attendance, Vacation Study, Examinations, Scholarships, Advice on Courses, and Departmental Leaflets, and the latter into References, Student Problems and Social Affairs. Before 1964 Wood and then Gibbs had served in that capacity with the Science Faculty Tutorship. When Dodd succeeded Gibbs as Faculty Tutor in the following session in 1965, Fox joined him as Departmental Tutor, assuming full responsibility of the post in 1966 when Dodd became increasingly involved with the introduction of the B. Sc. course-unit system. The procedure of admission of students began early in the first term with the arrival of the UCCA forms completed by applicants for admission to the department; following Dodd's procedure, these were scrutinized by Fox, who selected a list of candidates for interviews and carried them out in his room on the top floor. Typically an interview lasted about twenty minutes, beginning with questions about the interests and activities of the candidate, including any special references on the application form, then proceeding to ascertain the candidate's suitability for the selected course, and ending with the performance of some mathematical problems during my perusal of the practical physics notebook, which each candidate brought to the interview. In the early days a very good candidate, whose first preference was UCL, was given an AL 'pass-level' offer which had to be accepted or rejected; the standard offer was a grade C in both physics and mathematics; however a the offer for the combined Chemistry/Physics course was a grade B in physics, mathematics and chemistry. The interview being over, the candidate was taken downstairs, on a short tour of the three undergraduate laboratories. The progress of students in each of the three years was regularly reviewed at interviews during the first and second terms, and references written usually for third-year students.

In 1970 Imrie and Miller became Assistant Tutors, taking over student admissions to the department; and in 1974, when Fox became the College Schools Liaison Officer, McKenzie joined him as Tutor taking over responsibility for students, starting with that year's intake. McNally was appointed Departmental Tutor in Astronomy in 1965, Somerville succeeding him in 1970.

Teaching Administration

Gibbs became Superintendent and then Deputy Director of the Undergraduate Laboratories on Wood's retirement. After the occupation of the New Wing with the three undergraduate laboratories, Fox, R. C. Brown and effectively Heyland took charge of the first, second, and third-year laboratories under the general control of Gibbs. When Gibbs retired, the title of Deputy Director was abolished, Lush replaced Fox, Bullock replaced Brown, and Heyland became responsible for laboratory organization and student affairs for the foregoing laboratories under the leadership of Fox as head of the undergraduate teaching group. Two members of the academic staff and two postgraduate students were assigned to each of the first and second-year laboratories during each afternoon session, Heyland and project supervisors attending the third-year laboratory. Demonstrating, lecturing (including timetabling), tutoring and examinations were organized by Fox, later D. H. Davis taking over examinations; and Metheringham took charge of theatre demonstrations.

Professors' Meetings

In late September 1968 Prof. Massey suggested that informal and regular meetings of the departmental professors should take place to discuss the existing problems of the department and ideas for future development. Eight dates were fixed for these meetings during the session, starting with Friday, 18 October at 2.30 pm, followed by seven on Tuesdays at 3.00 pm between 5 November and 3 June. All of the meetings were on Tuesdays, except the first for which it was impossible to find a suitable Tuesday; Tuesdays were chosen to fit in with Professorial Board Meetings at 4.30 pm. In addition to the professors, Drs. D. G. Davis and Fox attended the meetings. At the first meeting Prof. Massey reported some proposed movements of research groups involving the Rocket, Infra-red, and Gargamelle groups. A general discussion of topics for consideration at future meetings resulted in the following:

(1) allocation of departmental resources;
(2) implications of three reports, two from the Committee on Manpower Resources for Science and Technology and one from the Council for Scientific Policy, namely:
'The Brain Drain; report of a Working Group on Migration', chaired by F. E. Jones, Managing Director of Mullard Ltd.;
'The Flow into Employment of Scientists, Engineers and Technologists', chaired Edinburgh University;
'Enquiry into the Flow of Candidates in Science and Technology into Higher Education, chaired by F. S. Dainton, V-C of Nottingham;
(3) the proposed Applied Physics course;
(4) the syllabus and effectiveness of the postgraduate courses;
(5) the grading of dissertations and the weighting in the final examination.

It was decided that the agenda of future meetings should be circulated with minutes of the previous meeting mainly reporting decisions taken; L. Castillejo would be the convenor and D. G. Davis, the secretary.

Topics for subsequent meetings included e. g., departmental grants, allocation to groups, academic and technical staff, academic staff meetings; staff-student relations, consultative committee and its library sub-committe; undergraduate teaching - introduction of new degree courses, syllabuses (arising from the implementation of the report of the Committee on Academic Organisation, chaired by Owen Saunders, Boards of Study function of approval of syllabuses was delegated to Schools without any formal requirement for involvement of staff other than the head of department), course-unit examinations, second marking of papers, assessment for honours, tutorials; intake of student, undergraduate and postgraduate; quinquennial development; future of astronomy in university, etc.

As an illustration of the financial allocation to the departmental groups, the following summary of their expenditure in the 1967-68 session, amounting to £364,538, is given:

 Undergraduate Teaching  
 Laboratories; Theatres; Development


 Theoretical Research  
 Atomic Physics and Astrophysics


 General Physics


 High Energy Physics


 Experimental Physics  
 High Energy:-  
 Bubble Chamber & Emulsion


 Spark chamber


 Atomic & Molecular:-  
 Ionic & Electronic


 Atomic Physics


 Molecular Beams


 Other Experimental Physics


 Space Science & Astronomy:-  
 Mullard Space Science Laboratory


 Infra-red Balloon


 Space Science & Atmospheric Structure


 Service Groups  
 Design Office


 Departmental Library


 Photographic Services


 Technical Physics


 Glass Laboratory








 Total Expenditure


Academic Staff Meetings

At the Professors' meeting on 13 January 1970, Prof. Massey recalled the requirements of the Professorial Board that each department should hold not less than two meetings of departmental staff in each session. He felt that such meetings were not adequate for good consultation amongst the staff, and asked what other arrangements could be made that might improve consultation. After extensive discussion it was agreed to make no changes in the existing arrangements for departmental staff or professors' meetings. There followed two Academic Staff Meetings on 22 May and 10 June, the first dealing with matters of general interest and the second with undergraduate syllabuses, teaching and examination methods.

The first meeting considered Communication Problems, Student Complaints, Libraries, Course Content, Lecture Theatres, and Educational Policy. There resulted a Departmental NewsLetter with seven issues from June 1970 to April 1971, and two special departmental lectures - 'A Personal View of High-energy Physics' by Prof. Heymann and 'X-ray Astronomy' by Prof. Boyd; the continuation of Prof. Massey's meetings once a term with representatives of each undergraduate year; a report of the student subscription lending library, controlled by the Library Sub-committee of the Staff-Student Consultative Committee; and the initiation of a central record of topics treated in sequence in courses. Attention was directed to College policy encouraging new members of staff to attend courses such as the 'Introductory Teaching Course for Lecturers 1971' to be given by the University Teaching Methods Unit at the Institute of Education. Prof. Massey expressed his views on possible changes in higher education which would affect the department, mentioning the increasing popular demand for higher education and the 'swing' from science as recorded in the Dainton report; the problem of retaining a good student intake into the department and the policy of concentration on specialised courses might need reconsideration. The meeting closed at 1.05 pm, having started at 10.30 am.

The second meeting considered proposals from the reconstituted Committee for Syllabus Revision (membership Burhop, Bullock, Castillejo (Chairman), B. G. Duff, Fox and Seaton) following its review of the syllabuses of the first-year courses, including a consultation of Duff with other first-year teachers. There followed a revision and a re-scheduling of the B1 and B11 courses, the former consisting of (i) mathematical techniques and (ii) pure mathematics (including 15 problem classes), and the latter consisting of (a) ideas of classical physics and survey of modern physics with (b) mathematical physics. Lectures in the first six weeks of the first term were confined to five per week of (a) and six per week of (i), the mathematical techniques being taught by a physicist. The number of first-year lectures was reduced by about 10% by unification of topics previously scattered throughout the courses, but mainly in the reduction of the lectures in the previous B1.

Two meetings were held in June 1971, the first dealing with general matters, e. g.,SRC Physics Committee proposals for course training for postgraduate students; amendments to University Regulations for Ph.D. permitting award of M.Phil. to Ph. D. candidates; technical staff restructuring; and the departmental situation in College - commencement next session of Executive Committee of the Professorial Board; College resources and their allocation; and Takeover, Letter from SRC chairman. The second considered proposals for changes to second-year courses, based on teachers' suggested revisions and Syllabus Revision Committee amendments designed to reduce content and lectures, to unify content of each unit and relate it clearly to the others, and to integrate theory with applications. Meetings continued to be held during Massey's tenure of the Quain chair and thereafter by his successors.

Staff-Student Consultative Committee

Following the recommendation of the Joint Committee (of the College Committee and Professorial Board) on Student Matters, this committee was formed primarily to improve staff-student relations; provided opportunities for the interchange of ideas or matters affecting students within the department and, when appropriate to make recommendations to the Head of the Department. It held its first meeting on 13 January 1969, the membership, with Prof. Massey's agreement, being 1 Professor (L. Castillejo), 1 Reader (R. E. Jennings), 1 Lecturer (A. J. Metheringham), Tutor to undergraduate Physics Students (J. W. Fox), 2 Postgraduate Students (K. S. Barnes & D. E. Burgess), 1 Third-year Student (Miss J. E. M. Cook), 1 Second-year Student (A. J. Morris) and 1 First-year student (J. C. Palfreman), the student members being elected being by their colleagues. Mr. Metheringham and Miss Cook were elected Chairman and Secretary respectively, although Miss Cook resigned on being elected Administrative Vice-President of the Students' Union in March and was replaced by Mr. Barnes. It held three further meetings during the session, considering three major topics on the basis of submitted reports, namely the structure of the B. Sc. course-unit degree, undergraduate tutorials, and practical work, Drs. G. R. Heyland, F. W. Bullock and G. J. Lush, staff in charge of the third, second, and first-year laboratories respectively being present for the last topic. A number of recommendations were made to Prof. Massey, the most significant being the establishment of a personal tutor system, the provision of model answers to the weekly problems to students and their tutors, and the re-organization of departmental notice boards; all were approved by Prof. Massey and put into effect. Following a discussion of the availability of undergraduate textbooks in the Physical Sciences Library, a Departmental Undergraduate Library was instituted and a Library Sub-Committe formed to be responsible for its operation. The membership of the sub-committee was the three undergraduate representatives of the Staff-Student Consultative Committee, one member of the academic staff appointed by that committee (A. J. Metheringham), the Librarian (Mr. C. A. R. Tayler, the Laboratory Superintendent), appointed by the Department, and three further undergraduates, one elected from each year. Four or five of each of the main textbooks and two or three of the others were housed in a small room attached to the first-year laboratory, one of each text being retained for use in the library, the rest being available for loan for one week, not renewable by the same borrower for the next week. The first meeting of the sub-committee was held on 26 October 1970 under the Chairmanship of Mr. Metheringham, Mr. C. A. R.Tayler, being elected Treasurer, and Miss L. J. Passmore as Secretary. A membership subscription of £6 was agreed with a third depreciation for the session. Mr. Tayler reported a membership of 86 of 143 undergraduates, 80, 58, and 42% of the first, second and third-year undergraduates respectively; the library had 203 books, 107 of which had been issued during its opening eight days. Mr. Metheringham reported that £550 had been spent on buying books, a £50-order being outstanding; including second-hand books costing £72, the average discount was c.11%, the expenditure being necessarily before any receipt of subscriptions.

Students' Societies

The oldest society having a membership involving physics and chemistry staff and students was the Chemical and Physical Society, first founded in 1834, but it did not last long, being absent form the first listing of societies in the 1854 Calendar; refounded on 9 November 1876, Oliver Lodge, then a part-time demonstrator in the department, was elected as President. The other old society embracing members of the mathematics and physics departments was the Mathematical and Physical Society, first listed in the 1903 Calendar. 1950 being the year for a 'Physics President' of the former society, Massey became President on taking up the Quain professorship. A new society, the Carey Foster Society, was formed just after Massey's entry to the department, more emphasis being placed on the social side of the student membership, e. g., welcoming freshers on the night before the commencement of the session, introducing them to the Carey Foster coffee room and showing them some of the department and college. The Astronomical Society, first listed in the 1959 Calendar, continued to thrive after the formation of the joint department. Both societies were mentioned under 'Living in London - Social Activities' in the departmental booklets containing information for prospective undergraduates, namely "these societies promote staff-student contact and enliven the social life of the department, by organising a variety of functions ranging from discos and cheese and wine parties to lectures by distinguished scientists."

Tea parties

Besides the departmental welcome party for freshers, parties were regularly held in the Men's Staff Common (later the Housman) Room each session for first, second, and third-year students. Additionally Massey, a professor and Fox regularly had tea in his room with delegations of students from each year. On one occasion, in 1970 Massey, Seaton and Fox met the whole second-year class at their request in place of the usual tea; among the matters discussed were some criticisms of their teaching and the assessment of course work. On another occasion, the Slade Film Unit shot scenes of the party in Massey's room involving him with Wilson, Fox and a third-year group; some were incorporated in the first College Film, copies of which were loaned to schools, Local Education Authorities, etc. primarily to aid recruitment of students.

Cumberland Lodge Weekend

The King George VI and Queen Elizabeth Foundation of St. Catherine's, established in 1947, is based at Cumberland Lodge in Windsor Great Park, its main concern being with the universities, particularly university students. The departmental week-end started in the 1963-64 session after some visits by a group of members of the Departments of Physiology, Psychology and Physics, organised by Denis Noble of Physiology. The first weekend, from 24-27 April 1964, was entitled 'Attitudes and Methods in Physical Research' and involved an introductory session, 'Why Research?' by E. H. S. Burhop, after dinner on the Friday evening. On Saturday morning there were two sessions; 'Research - Pure or Applied?' by D. W. O. Heddle and M. J. B. Duff, and 'Experimental and Theoretical Approaches' by J. B. Hasted and S. Zienau. After tea Sir Harrie Massey discussed 'The Research Programme of the Department' and after dinner there was 'Laboratories in extensio' by F. F. Heymann and A. P. Willmore. On Sunday there were two sessions, one before and the other after dinner; the former being 'Not only Physicists' by D. G. Davis and F. R. Stannard, and the latter,'Undergraduate Courses - A Preparation for Research' by C. Dodd. There were some 50 participants, half being third-year students. A second weekend took place in 1964, namely from 27-30 November, 'Aspects of University Research in Physics' by R. L. F. Boyd, A. Donnachie and H. B. Gilbody being followed by 'Research in an Industrial Laboratory' by G. A. Gough of Hawker Siddeley Dynamics Ltd. and 'Research in a National Laboratory' by G. H. Stafford of the Rutherford High Energy Laboratory. The November 1965 weekend on 'Experiment and Theory in Modern Physics' included a Saturday evening session on 'St. Catharine's' by Anthony Bland, the Principal of the Foundation. The opening session of the 1966 November weekend, 'Physicists - Supply and Demand', covered a survey of published material on the employment of physicists, and the pre-luncheon session on Saturday, 'Careers for Physicists' was given by R. C. Brown, who had succeeded Orson Wood as the College Careers Adviser in 1961. The Sunday evening sessions were 'The Impact of Computers on Research' by F. F. Heymann and 'Undergraduate Teaching', a discussion started by J. W. Fox.

I succeeded Douglas Davis as organiser of the weekends for the fifth, held from 26-29 January 1968, until my retirement from the department in September 1983. The records show 41 third-year undergraduates, 4 postgraduates, 11 members of staff staying and 5 visiting the Lodge - a full complement! The students were charged £1 each, the department paying a subsidy of £2.5 for each of them. The opening session after dinner was 'How an ethologist might see a physicist' by L. Castillejo. Three of the Saturday sessionswere 'Atomic Physics as a Career', R. F. Stebbings; 'New Forms of Astronomy', A. P. Willmore; 'High Energy Nuclear Physics as a Career', F. F. Heymann, the fourth being the usual pre-prandial one by Sir Harrie Massey. The two Sunday sessions were 'Big Science' by E. H. S. Burhop and 'A Discussionof Undergraduate Problems' under my Chairmanship.

In later years the weekend, starting on the last Friday in October, proved the most convenient; some second-year students were included in the party, some staff continued to stay for the whole week-end, others visiting, and Massey always coming on Saturdays at tea-time for his session between tea and dinner. A 52-seater coach was used to take the students and me to and from the Lodge. The programme of the week-end of 25-28 October 1974 is reproduced below, this being the last one under Massey's headship. The party comprised 53 undergraduates, 5 postgraduates and 19 staff, including Ian McKellar, the College Careers' Adviser.

Friday:25 October
6.45 pm Sherry Party
7.15 pm Dinner
8.45 pm UCL participation in H.E. physics research at C.E.R.N. F. F. Heymann

Saturday: 26 October
8.15 am Breakfast
10.00 am C.U.S.C. - Can computers assist learning? J. McKenzie
11.00 am Tea
11.30 am Observation of compact X-ray sources P. W. Sanford
1.00 pm Lunch
4.30 pm Tea
5.00 pm Sir Harrie Massey
7.15 pm Dinner
8.30 pm Artificial intelligence M. J. B. Duff

Sunday: 27 October
9.00 pm Breakfast
1.00 pm Lunch
4.30 pm Tea
5.00 pm After University I. D. McKellar
7.15 pm Dinner
8.15 pm General discussion Chairman: J. W. Fox

Monday: 28 October
8.00 pm Breakfast

As will be seen, there was plenty of free time for staff and students to take advantage of the recreational facilities at the Lodge; occasionally some of them attended the Sunday morning service in the Royal Lodge Chapel.

Annual Cricket Match

Another feature of departmental life was the annual staff/student cricket match played at Shenley, the staff team being captained by Massey. He was a very good cricketer, having played for the Cavendish Club and being captain in 1933 when the club won the Inter-Laboratory cup. He played club cricket regularly at Belfast and then at Chislehurst, where his prowess gained the Hobbs bat, presented by the great man himself. The Australian test wicket-keeper, B. A. Barnett, is recorded as considering him to be a potential professional player. Massey told Bates that his success as a player was mainly due to his exceptionally fast reaction time; Bates (loc cit) adds that he was exceptionally fast at anything dependent on his mental processes - reading, writing, understanding, mathematical analysis.

Institute of Education Courses

In the late sixties and early seventies the department ran a series of triennial courses on Modern Trends in Physics in relation to the work of the Sixth Form for the Institute. The courses were designed for sixth-form teachers of physics and were held in the lecture theatres and laboratories of the department. As an illustration of the courses, the programme for the course held between 29 June and 4 July 1970 is given below; seventeen members of the department and Prof. P. A. Samet, Director of the Computer Centre, were involved in the course. Residential members of the course stayed in the Institute's John Adams Hall; a special collection of books was displayed at the University Book Shop (later Dillons); and members were allowed to use the College General and Physical Science & Engineering Libraries for reference purposes.

After an early evening reception and sherry party at the Institute, including an introduction of the course, on Monday 29 June, the course started at 9.30 a.m. on Tuesday at UCL, the programme being as follows:

Tuesday,30 June:
9.30 am Prof. Burhop; Physics in the seventies
10.20 Discussion
10.35 Coffee
10.55 Prof. Heymann; Elementary particles
11.45 Discussion
12.00 Lunch
2.00 pm Dr. R. C. Brown; Careers for physics graduates
3.30 Tea
4-5.30 Research laboratories open for inspection

Wednesday,1 July:
9.30 am Prof. Boyd; X-ray astronomy
10.20 Discussion
10.35 Coffee
10.55 Dr. Jennings; Infra-red astronomy
11.45 Discussion
12.00 Lunch
2.00 pm Mr. Metheringham; Projects and special courses in undergraduate practical work
3.30 Tea
4-5.30 Undergraduate laboratories open for inspection

Thursday, 2 July:
9.30 am Prof. Seaton; The origin of the chemical elements
10.20 Discussion
10.35 Coffee
10.55 Dr. Griffith; Collisions of positrons with molecules
11.45 Discussion
12.00 Lunch
2.00 pm Dr. Fox; Assessing performance in sixth-form practical physics
3.30 Tea
4-5.30 Research and undergraduate laboratories open for inspection

Friday, 3 July:
9.30 am Dr. Samet; Computer science as an academic discipline
10.30 Discussion
10.35 Coffee
10.55 Scientific films
12.00 Lunch
2-5.30 All laboratories and Computer Centre open for inspection

Saturday, 4 July:
10.00am General discussion, chaired by Mr. Underwood of the Institute
11.00 End of course

It is interesting to note that the course was numbered 930 by the Institute; successive courses were run in 1973 and 1976, but those arranged for 1979 and 1982 were cancelled owing to lack of applicants.

Student Numbers

In 1965, on the advice of Massey, the Provost (Sir Ivor Evans) appointed Dr. A. W. Barton on a part-time basis to help with the recruitment of students into the science departments of the college. Incidentally Barton, the son of E. H. Barton, F.R.S. (one-time Professor of Physics at Nottingham) read physics at Cambridge, being Senior Scholar of Trinity College. After his Ph. D. degree for research in the Cavendish Laboratory, he took up schoolmastering on Rutherford's advice, becoming Chief Physics Master at Repton and successively Headmaster of King Edward VII School, Sheffield and the City of London School. He was a commanding figure in the Headmasters' Conference, and being a first-class soccer referee, was active in the Football Association. He became Advisor for Recruitment of Science Students in 1966 and the first Schools Liaison Officer of the College in 1966. In 1971 Barton was succeeded by Mr. M. W. Brown, a Cambridge mathematician, who had taught at the Bec School, Wilson's Grammar School and Wandsworth Training College before becoming Deputy Head of Peckham Boys' School and then Head of Charlton and Holloway School - the latter being one of the earliest London schools to be re-organised on a comprehensive basis. He joined the I.L.E.A. in 1960 as a District Inspector (Mathematics), becoming a Staff Inspector (General) in 1963. Whereas Barton made his biggest impact in the independent sector, Brown made a complementary contribution mainly in the maintained sector, including the L.E.A. Careers Advisory Service. When the time came to review Brown's appointment, it had become evident that his successor should be chosen from someone with an intimate knowledge of the College, some involvement with the schools, and some experience of the problems faced by admission tutors. Hence my appointment to succeed Brown in 1974 on the recommendation of the Faculty Tutors. With the approval of Massey and his successor, Heymann, I was able to develop the job, devoting as much time to it as seemed in the best interests of the College within the framework of my departmental duties of Head Tutor and Head of the Undergraduate Teaching Group.

Undergraduate admissions during the last ten-year Massey period are tabulated below, the second column recording the total number of candidates applying for physics and the other columns recording the number applying for the relevant UCL courses, the numbers in parenthesis being those admitted.

   National  UCL        
Year  Physics  Physics  App/Phys  Chem/Phys  Astron  Astron/Phys
1965 2749 641(42)     58(8)  
1966 2367 467(43)     77(10)  
1967 2436 358(52)     76(8)  
1968 2578 375(54)   22(0) 84(6)  
1969 2738 323(47)   49(8) 99(9)  
1970 2795 280(35) 42(7) 34(4) 137(23)  
1971 3017 268(37) 67(19) 41(9) 132(20)  
1972 2807 216(31) 43(9) 46(6) 135(18)  
1973 2579 194(24) 46(4) 40(6) 149(22)  
1974 2471 158(24) 34(7) 17(2) 113(21) 111(16)
1975 2295 181(30) 22(3) 32(6) 98(30) 110(13)

Drop-out Statistics

For each session from 1968 to 1974, the number of students (percentages in brackets) not proceeding to the second and third year of each course are given in the first and second rows respectively, the analysis in the columns - A(academic failure); B(transfers to other colleges and within UCL); C(left for medical reasons); D(left at own request); E(total) - being normal Faculty of Science procedure.

   Session  Course  A  B  C  D  E
   1968  Phys  4 (7.7)  3 (5.8)  0  1 (1.9)  8 (15.4)
       0  0  1 (2.8)  2 (5.6)  3 (9.4)
     Ast  1 (12.5)  0  0  0  1 (12.5)
       0  0  1 (14.3)  0  1 (14.3)
   1969  Phys  1 (2.0)  2 (4.0)  0  1 (2.0)  4 (8.0)
       4 (9.3)  0  1 (2.3)  0  5 (11.8)
     Ast  0  0  0  0  0
       0  0  0  0  0
   1970  Phys  2 (4.3)  2 (4.3)  0  2 (4.3)  6 (13.0)
       2 (4.3)  0  0  0  2 (4.3)
     Chem/Phys  1 (12.5)  1 (12.5)*  0  0  2 (25.0)
     Ast  1 (11.1)  1 (11.1)  0  0  2 (22.2)
       0  0  0  0  0
         *Chem/Phys: transfer to Phys
   1971  Phys  1 (2.9)  1 (2.9)  0  3 (8.6)  5 (143.4)
     4   (9.8)  0  1 (2.4)  0  5 (12.2)
     App Phys  2 (28.6)  0  0  1 (14.3)  3 (42.9)
     Chem/Phys  0  1 (25.0)*  0  0  1 (25.0)
       0  0  0  0  0
     Ast  1 (4.3)  0  0  1 (4.3)  2 (8.6)
       0  0  0  0  0
         *Chem/Phys: transfer to Phys
   1972  Phys  5 (13.9)  4 (11.1)  0  0  9 (25.0)
       8 (25.0)  0  0  0  8 (25.0)
     App Phys  1 (5.3)  5 (26.3)  0  0  6 (31.6)
       0  0  0  0  0
     Chem/Phys  1 (11.1)  0  0  0  1 (11.1)
       0  0  0  0  0
     Ast  0  0  0  1 (5.0)  1 (5.0)
     5 (23.8)  0  0  0  5 (23.8)
   1973  Phys  4 (12.9)  0  0  0  4 (12.9)
   2 (7.1)  0  0  0  2 (7.1)
     App Phys  1 (11.1)  0  0  0  1 (11.1)
       0  0  0  0  0
     Chem/Phys  0  0  0  0  0
       1 (14.3)  0  0  0  1 (14.3)
     Ast  0  0  0  1 (5.5)  1 (5.5)
       1 (5.3)  1 (5.3)  0  0  2 (10.6)
   1974  Phys  2 (8.3)  0  0  2 (8.3)  4 (16.6)
       0  0  0  0  0
     App Phys  0  0  0  0  0
       0  0  0  0  0
     Chem/Phys  0  1 (50.0)*  0  0  1 (50.0)
       0  0  0  0  0
     Ast  1 (5.9)  0  0  3 (17.6)  4 (23.5)
       2 (11.1)  0  0  1 (5.5)  3 (16.6)
     Ast/Phys  2 (11.8)  5 (29.4)*  0  0  7 (41.2)
         *Chem/Phys: transfer to Chem Eng;
 Ast/Phys:3 transfers to Ast, 2 to Phys

Postgraduate Students

The number of postgraduate students in the department increased to 29 in Massey's first session, special lecture courses for them being given in radiation theory, theory of spectra, nuclear physics, and atomic collision phenomena; in addition seminars in nuclear physics, and electronic and ionic physics were regularly held. Throughout substantial coherent courses of lectures and seminars were provided, and all students were required to attend some courses during their first year. Lectures in high energy physics were arranged on a collaborative basis with Queen Mary and Westfield Colleges; those in astronomy and space research, and in atomic and molecular physics were mainly given by departmental staff, with collaboration from some honorary staff in SRC laboratories. A small number of students took courses at other schools of the University, particularly Imperial College.

An M.Sc. course in theoretical physics was given at times during the mid-fifties to the mid-sixties; from 1962 to 1965 it was designated 'M.Sc. course on Theoretical Atomic and High Energy Physics'. The College Diploma in Space Science (one year full-time, two years part-time) was instituted in the 1962-63 session; this course was directed by G. V. Groves, who gave almost all the lectures required (see p. 101).

Dr. M. J. B. Duff was Tutor for Admission of postgraduate students; before the introduction of new M.Phil. research degree (one of the results from the 1965-66 Saunders's Committee on Academic Organization) all research students registered for the Ph. D. degree; afterwards they registered for the M.Phil. for the first year, normally transferring to the Ph.D. in their second year. Massey was keen to recruit his own students, the procedure after the introduction of the course-unit degrees being as follows: after the lunch for the external examiners in the Whistler Room, I announced the degree classifications to the assembled finalists in the small theatre on the fourth floor, finishing by "Professor Massey wishes to see all those having gained first-class honours, and any others who would like to see him". Interviews followed in his room, Messrs. Duff, Fox, D. G. Davis and sometimes Burhop also being present, and SRC studentships were allocated to students, some of whom having previously expressed their preferences for particular research groups.

In 1973 the department received a quota of 11 SRC studentships, namely 3, Nuclear Physics; 3, Space Research; 3, Astronomy; and 2, Physics. 4 studentships were awarded 'on appeal' and 1 as an 'instant', making a total of 16. It was understood that Professor A. H. Cook's panel advising the SRC on the research programme of the Mullard Space Science Laboratory had recommended an increase of 2 in the number of space research studentships. As recorded on p. 70 the Committee reviewing the resources of the department noted that there was an increase of postgraduate students from 65 in 1973 to 70 in 1976, but there was little chance of realising the capacity of 100 owing to the numbers of studentships and suitably qualified candidates then available.

Massey: concluded

In conclusion further reference is made to Massey's Royal Society Biographical Memoir (B.B.D), following closely Boyd on Space Research, Davis on Scientific Policy, and Bates on the Royal Society etc.

Space Research (1953-78)

M. O. Robins in the preface to the History of British Space Science, written by Massey and Robins, writes "Space Science in Britain was initiated, and the foundations for its development were laid, very largely by one man, the late Sir Harrie Massey". Massey's involvement at the outset has been sketched on p. 87, following his Chairmanships of the Royal Society's Gassiot Committee in 1951, its Rocket Sub-Committee in 1955, and Artificial Satellite Sub-Committee of the National I.G.Y. Committee in 1956. Ten days after the launch of 'Sputnik 1', the Artificial Satellite Sub-Committee met and decided to set up two working parties, one on the scientific value of satellites, the other on radio, optical, and computing methods of study. After the first successful Skylark experiments at Woomera in 1957, the requirements of the national rocket programme and the scientific and policy matters relating to satellites led Massey to set up in the department a Space Management Unit headed by Robins, who was seconded from the Ministry of Supply. The decision of the Bureau of the International Committee of Scientific Unions to establish a special Committee on Space Research (COSPAR) led to Massey's attendance at the preparatory meeting at the Royal Society in November 1959 as the nominee of the British I. G. Y. Committee; the meeting set up a five-man Executive Council, including Massey; and in December the Royal Society decided to appoint a British National Committee on Space Research with Massey as chairman, an office he discharged energetically for a quarter of a century. Massey served as a Bureau member of COSPAR until 1978 and the importance of his role in the National and International Space scene at this seminal time cannot be overestimated.

As soon as it existed, Massey led the National Committee into a study of the U. K. way ahead by setting up two sub-committees, one for Tracking and Data Recovery, the other for Design of Experiments. The latter, under his chairmanship, immediately considered the provision of satellite flight opportunities for British scientists. There resulted the development of the U. K. launching system at Woomera, with Commonwealth cooperation, opportunities on American rockets, and European cooperation. A launcher development based on the Blue Streak intermediate range ballistic missile project, possibly using a development of Black Knight as the second stage was considered with the view of orbiting a stabilized ultra-violet telescope. In the event the Prospero satellite launched into orbit by a Black Arrow vehicle on 28 October 1971 was the only all-British launching system. However Massey's big-thinking approach led to the successful IUE collaboration of the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) of the USA.

As recorded on p. 88, NASA'S offer to launch suitable space experiments without charge for other countries led to the launching of Ariel 1 on 26 April 1962. Within six weeks of the offer, Massey had set up working groups of his Design of Experiments Sub-committee in seven different disciplines to make proposals for suitable experiments. The unusual method of financing the NASA-UK cooperative space programme owed much to Massey's personality and his dedication to university science: namely, a Steering Group, including Massey, set up within the office of the Lord President of the Council, who was also Minister for Science, had responsibility within the Government for space policy and finance, but the scientific programme rested with the British National Committe for Space Research, that was Massey and the Royal Society, financial caring being carried out by the Department of Scientific and Industrial Research (DSIR).

During the late fifties and early sixties Massey sought to share his vision and enthusiasm with scientists and statesmen in Australia, Canada, India, New Zealand and Pakistan. He became Chairman of an informal Consultative Space Research Committee, which met in Colombo, Ceylon in 1968 and planned a useful programme of mesospheric and lower ionospheric research.

Massey played a key role in bringing about the European Space Research Organization (ESRO), which arose following the success of CERN at Geneva. It was discussed with Massey at the COSPAR meeting in January 1960, and after a small meeting with senior European scientists in February, he arranged a more formal meeting in April at the Royal Society by invitation of the British National Committee on Space Research. Although absent in Australia, the studies of working groups he had set up earlier, together with the Skylark experience and the start on UK-1 (Ariel 1), enabled the UK to play a leading part at the meeting. There followed the formal establishment of a Preparatory Commission for European Space Research, which held its first meeting in Paris on 13-14 March. Massey was elected chairman of a small bureau to make arrangements for an intercontinental meeting to set up the Commission; consequently he chaired a meeting for technical discussion at the Royal Society. The intergovernmental meeting was held in Geneva on 28 November, Massey being elected chairman and presiding as he called the head of each government's delegation to sign the protocol. When the Commission convened in Paris in the early Spring, he was elected President, both of the Commission and its inner bureau. More than three years elapsed before the first meeting of the ESRO Council, during which Massey's energy at home and diplomacy abroad not only set the mould of ESRO for years ahead, but also got a research programme agreed and started before the organization had been ratified.

Massey relinquished his Chairmanship of the ESRO Council towards the end of 1964. His appointment as Chairman of the Council of Scientific Policy (CSP) in January 1965 restricted his activities on space research affairs, although he was frequently consulted by ESRO and its successor, the European Space Agency (ESA). The establishment of the Research Councils resulted in the removal of the executive control of UK space research policy from the Royal Society's National Committee to the Science Research Council (SRC). However Massey continued to attend meetings of the Astronomy Space and Radio Board and of the SRC influencing policy. His frustration at not getting any of the ESRO institutes in the UK probably led to the acquisition of the Mullard Space Science Laboratory at Holmbury House in 1965, recorded on p. 61.

ESA had a wider remit than ESRO and in 1972 its scientific programme was giving grounds for concern. Massey saw that NASA had managed to maintain a prime role for space science benefiting from its close consultations with the Space Board of the National Academy of Sciences. He called together senior European space scientists and became Chairman of a Provisional Space Science Board for Europe, having representative exchange with the corresponding USA Board. In 1974 the European Board became the Standing Committee on Space Research of the European Science Foundation, Massey being Chairman until 1978.

Science Policy (1953-83)

Massey's early involvement in science policy was in areas of physics in which he was particularly interested, namely space and nuclear physics research. He was a member of the Department of Scientific and Industrial Research (DSIR) Nuclear Physics Sub-Committee from 1956; the Research Grants Committee from 1959; and the Governing body of the National Institute for Research in Nuclear Science from its foundation in 1957. In January 1965 the Secretary of State for Education and Science appointed the Council for Scientific Policy to advise him on civil science policy, Massey being Chairman. At the same time a Bill was going through Parliament, which became the Science and Technology Act 1965, providing for the establishment by Royal Charter of the Science and Natural Environmental Research Councils, and for the transfer to them of many of the former functions of the DSIR, which was then dissolved. The Research Councils were financed directly by the Department of Education and Science and the industrial research responsibilities of the DSIR were transferred to the Ministry of Technology. The full members of the CSP were all distinguished scientists and the heads of the four Research councils and the Chairman of the UGC were assessors. The CSP was required to provide both general advice on civil science policy and also specific advice on the programmes and financial needs of the Research Councils. During the previous decade Research Council expenditure had grown at an annual rate of around 13% in real terms and it was necessary to find a way towards a rate much closer to the GNP rate without serious damage to science. Massey set up working parties to study the problem; the Research Councils were invited to consider their long-term programmes and to develop the justification for their policies, 'both in terms of intrinsic scientific criteria and in relation to their educational, social and economic benefits'.

Some of the studies were toward specific measures to improve the 'scientific environment'. The first group to report was that chaired by Prof. B. H. Flowers on computers for research; it recommended a major programme of computer installation in the universities and research councils over a five-year period and the establishment of a Computer Board to coordinate the assessment of computing needs and provision. The proposals were strongly endorsed by the CSP and they were accepted by the Government at the end of 1965, with implementation over six rather than five years. Another group, chaired by Sir Gordon Sutherland, studied liaison between universities and Governmental research establishments. Its report in March 1967 dealing with the outstanding success of the Medical Research Council Unit in Molecular Biology not being balanced by a comparable development in teaching the subject led to the Group on Molecular Biology, chaired by Dr. J. C. Kendrew, examining the field and reporting back in July 1968.

Some evidence of a trend away from science in school sixth forms led to a working party, chaired by Prof. F. S. Dainton, set up to enquire into the flow of candidates in science and technology into higher education; it included members of the Committee on Manpower Resources for Science and Technology and produced an interim report in February 1966.

Massey always considered the universities to be the main centre of scientific activity, and the CSP appointed a group under his chairmanship 'to consider, with representatives of the University Grants Committee, how best to examine fully the policy and machinery for the support of research in the universities'. This led in April 1967 to a joint working group of the CSP and UGC 'to study criteria for the development of the system of support for scientific research in the universities giving particular attention to the implications of retaining initiative and freedom of manoeuvre for the individual researcher'. Again Massey led this group, which reported in October 1971, after the end of his chairmanship of the CSP. The report constitutes one of the most cogent statements for the continuation of the 'dual support system' of the UGC and the Research Councils

The CSP regarded international scientific relations as of the utmost importance and established a standing committee, with Massey as chairman, on the subject, the membership including representatives of the Royal Society and appropriate Governmental departments. A wide range of topics were considered, including measures to promote mobility of European scientists, and the possibility of European cooperation in molecular biology. The first led to a European fellowship scheme, administered by the Royal Society, and the second contributed to the establishment of the European Molecular Biology Organization some years later.

As recorded on p. 61, Burhop spent the 1962-63 session at CERN serving as secretary of the Amaldi Committee considering the future policy for accelerators in Europe. Its first proposal was accepted, the Intersecting Storage Rings being built. The second proposal resulted in further studies, culminating in detailed proposals to the CERN Council for a 300 GeV machine. Nine possible sites for the machine, including one at Mundford in Norfolk, were considered. In March 1967 the CSP set up a working group, chaired by Prof. M. M. Swann, to examine the implications of the proposed accelerator for the balance of the UK scientific effort, both national and international; and to assess the wider effects of implementing the proposal. The Nuclear Physics Board of the SRC strongly backed the proposal, but the SRC was naturally more divided. The SRC included provision for UK participation in the proposed accelerator in the Five-Year Forward Look submitted to the Department of Education and Science in May 1967, and advised the Secretary of State that the UK participation should be subject to various safeguards, the most important being the protection of the proper development of other disciplines; Massey and Nyholm formally dissented. The proposal presented the CSP with the 'big science versus little science' dilemma in stark form. The CSP endorsed the SRC recommendation, noting that the cost could be accommodated in a nuclear physics budget rising at an average annual rate of 7%, and recommending that the balance in favour of other fields of science should be redressed by an annual growth over the next decade of 9%. The various reports, including an economic assessment of the siting a 300 GeV laboratory in the UK instead of in another CERN member state, were published in January 1968. Although the SRC was prepared to accept lower growth rates and reduce the national programme of nuclear physics, the government in June 1968 decided on financial grounds against the participation of the UK in the 300 GeV project. The eventual outcome turned to be a happy one; after some protracted international discussions over costs and sites and further design studies, led by Dr. J. B. Adams, who had been a member of the CSP, revised cheaper proposals were accepted by the CERN Council in February 1971, with the support of the UK delegate, for a Super Proton Synchrotron at CERN using the existing Proton Synchrotron as an injector. This machine was built under Adams's direction, and members of the department, e.g., the Emulsion Group (see p. 80), were prominent among its users.

During Massey's chairmanship of the CSP a series of Science Policy Studies were published, mostly by members of the Secretariat, covering issues such as 'The sophistication factor in science expenditure' and 'An attempt to quantify the economic benefits of scientific research' on topics of interest to the CSP. Massey's term of office as chairman of the CSP finished at the end of 1969.

One important field of science policy in which Massey played a unique role was in UK-Australian collaboration. In the mid-sixties proposals for a major optical telescope in Australia were under discussion and in 1966 the SRC decided to give high priority for a joint UK-Australian 150 inch optical telescope. Massey supported the project on the grounds of being the most practicable way of providing good observing facilities in the Southern Hemisphere for British and Australian astronomers, and he helped the project along during its formative period. The construction of the telescope started in 1967, but the replacement of a Joint Policy Committee of the Australian Department of Education and Science and the SRC by the Anglo-Australian Telescope Board had to await the passing of the Anglo-Australian Telescope Agreement Act by the Australian Parliament in 1970. Massey was appointed a UK member of the Board, as Deputy Chairman in 1975 when the telescope was passing from the commissioning to the operational stage, and in 1980 he became Chairman, holding the office until 1983. At a Board meeting, which he was too ill to attend, it was decided to name the base laboratory in Epping after him.

After being Chairman of the CSP, Massey undertook fresh responsibilities: Physical Secretary of the Royal Society, 1969; Vice-Provost of UCL, 1969; Royal Society assessor on both the Astronomy and the Space Policy and Grants Committees of the SRC's Astronomy, Space and Radio Board, continuing in the latter role through various changes in the organization of the SRC, including the change of name to Science and Engineering Council.

Royal Society: Council Service (1949-51), (1959-60); Physical Secretary and Vice-President (1969-78).

An officer who served on the Council with Massey, The Treasurer, Sir John Mason, wrote "One of Massey's greatest contributions to the promotion and support of science in his later years was his outstanding service as Physical Secretary of the Royal Society. He held this onerous position for an unusually long period of nine years, from 1969-1978, serving under three presidents, Blackett, Hodgkin and Todd. In this office, which gave him much pleasure and satisfaction, Harrie Massey brought all his great gifts of creativity, wisdom, foresight and energy to bear on a whole range of issues under consideration by the Society as it was extending the scale and scope of its national and international activities and taking a much more active and positive role in science policy and public affairs."

He goes on to recall Massey's involvement in the controversial discussions on the organization and management of governmental research and development, culminating in the Rothschild proposals on which he had strong reservations; his even more decisive role after the Executive Secretary, Sir David Martin, died suddenly in December 1976 when the Treasurer, Biological Secretary and Foreign Secretary had been in office for only two weeks and the President for only a year. Harrie Massey kept "the ship on an even keel while the new crew was learning the ropes and it was largely due to his excellent judgement and calm authority, derived from a vast experience of people and situations, that the Society was able to undertake many new initiatives and changes with little disruption or dissension".

He refers to one of Massey's major tasks, namely, to chair a committee set up by the Society to review the functions and operations of the Ordnance Survey; this complex study starting in 1973, led to major representations to the Serpell Committee in 1979, and to further representations to the Secretary of State for the Environment in 1981.

Mason recalls Massey organizing, with others, a scientific discussion meeting almost every year from 1973 to 1980 with three separate discussions in both 1974/5 and 1977/8. He concludes with a supplement of undertakings additional to what might be thought of as the normal duties as Physical Secretary; some 30 items are listed, starting with 1970 March, R.S. delegation to Japan and ending with 1980 December, further submissions on Ordnance Survey.

Honours and Distinctions

The Sovereign: Knight Bachelor 1960.
Royal Society: Fellow 1940; Hughes Medal 1955; Royal Medal 1958; Rutherford Memorial Lecture 1967;
Council Service 1949-51, 1959-60; Physical Secretary and Vice-President, 1969-78.
Other learned societies: Royal Astronomical Society: Vice-President 1950-53, Gold Medal 1982. Honorary
Member, Royal Meteorological Society 1967. Physical Society: President 1954-56, Honorary Fellow 1976. Corresponding Member of Australian Academy of Science 1976, of Academy of Science, Liege 1967. Member, American Philosophical Society 1975.
Universities: Honorary Doctorates: Melbourne 1955, Belfast 1960, Glasgow 1962, Leicester 1964, Hull 1968,
Western Ontario 1970, Melbourne (again) 1974, Adelaide 1974, Heriot-Watt 1975, Liverpool 1975, York 1981, Ontario 1981. Honorary Fellow, University College London 1976.
Miscellaneous: Founder Member, Atomic Scientists Association, Vice-President 1949-53, President 1953-57. Anglo-Australian base laboratory building, named Massey Building 1984. Member, Middlesex County cricket Club and Melbourne Cricket Club; Awarded Hobbs cricket bat 1939.


Books (and lectures, separately published)

The theory of atomic collisions (with N.F.Mott) 1933; Oxford, Clarendon Press, (2nd & 3rd edn, 1949 & 1965).
Negative Ions 1938; Cambridge Univ Press, (2nd & 3rd edn, 1950 & 1976).
The atom and its nucleus 1950; Univ of Queensland, Brisbane.
Electronic and ionic impact phenomena (with E.H.S.Burhop) 1952; Oxford, Clarendon Press, (2nd edn with H.B.Gilbody, also 5 vols., 1969-1974).
Atoms and Energy 1953; London, Elek Books, (2nd edn, 1956).
The upper atmosphere (with R.L.F.Boyd) 1958; London, Hutchinson, (2nd edn, 1960).
Ancillary Mathematics (with H. Kestelman) 1959; London, Pitman, (2nd edn, 1964).
The new age in physics 1960; London, Elek Books, (2nd edn, 1967).
Basic laws of matter (with A.R.Quinton) 1961; Bronxville, N.Y., Herald Books.
Scientific research in space (with M.O.Robins, R.L.F.Boyd, G.V.Groves & D.W.O.Heddle) 1964; London, Elek Books.
Space Physics 1964; Cambridge Univ Press.
Space travel and exploration 1966; London, Taylor & Francis.
Atomic and molecular collisions 1979; London, Taylor & Francis.
History of British space research (with M.O.Robins); 1984; Cambridge Univ Press.
Applied atomic collision physics 1982 (Editor with E.W.McDaniel & B.Bedserson, 5 vol); N.Y. Academic Press.
Negative ions by B.M.Smirov, translated by S. Chomet (Editor) 1982; London, McGraw-Hill.
Report of a study on the support of scientific research in the universities (commissioned by the Council for Science Policy) 1971; London, H.M.S.O. (Cmnd 4798).

Scientific papers

221 are listed in B.B.D., starting with 'The theory of the extraction of electrons from metals by positive ions and metastable atoms' (Proc Camb Phil Soc 26,386-401 and ending with 'Summary lecture in Fundamental processes in energetic atomic collisions' (ed H.O.Lutz, J.S.Briggs & H. Kleinpoppen), pp. 659-668; N.Y. Plenum Press.

After his retirement in 1975, Massey regularly came into the department, Margaret Harding, the departmental secretary, continuing to do some of his work; despite his long painful illness, he soldiered on, towards the end, coming in with an arm in a sling. Massey died from bone cancer on 27 November 1983; Sir David Bates gave the address at his funeral service on 2 December in Christ Church, Esher, the coffin being draped with the Australian flag. Some members of the department attending the service accompanied the family to the interment in Long Ditton cemetery

A Memorial Service was held for Sir Harrie at noon on Thursday 8 March 1984 in The University Church of Christ the King in Gordon Square, WC1. Sir David Bates delivered the address, the Provost, Sir James Lighthill, and the President of the Royal Society, Lord Todd, read.

The College established an Appeal Fund to honour Massey's memory, income from the fund supporting the Massey Medal, awarded biennially to an individual making an outstanding contribution to space research, the recipient being selected by the Royal Society on the basis of nominations by COSPAR and presented at the Plenary Sessions of COSPAR; and an annual Massey Memorial Lecture commemorating his outstanding service to science and to the College.


B  Bellot, H. Hale: University College London, 1826-1926; Univ. of London Press Ltd., 1929.
D.N.B.  Dictionary of National Biography.
D.L.U.  Description of the London University, 1828; (College Archives).
 Wood, D.O.: About the Physics Department, University College London
 and those who worked therein, 1826-1950 (Typescript, College Archives).
K  Ker, W.P.: Editor, Notes and Materials for the History of U. C. L. (College Archives).
P  Porter, A.W.: Department of Physics (Typescript, College Archives).
 Grant, W.: Manuscript dealing with the history of the College in general
 and of the Physical Department in particular (College Archives).
H & N  Harte, N. & North, J.: The World of University College London 1828-1978; Published by U.C.L.
M & R  Massey, Sir Harrie & Robins, M.O.: History of British Space Research; Cambridge Univ. Press 1986.
 Bates, Sir David; Boyd, Sir Robert & Davis, D.G.: Harrie Stewart Wilson Massey, 1908-1983;
 Royal Society Biographical Memoir, Volume 30, November 1984.

College Archives consulted were Annual Reports from 1827 onwards; Calendars - London University, 1831, UCL 1853/4 onwards; Distribution of Prizes and Certificates of Honour, 1828/9-1851/2.
Manuscripts were Minutes, Council 1825-1907, then Committee 1908 onwards.
Apparatus Book, Natural Philosophy, 1827-30; Apparatus Book, 1862 and a somewhat earlier version thereof; List of Physical Apparatus, 1866-73.
Attendance Register, 1881-92.
The Admission of Women to University College London; A Centenary Lecture; N.B.Harte, UCL 1979.
Department of Physics Research Reports (ed. M.J.B.Duff) 1964/5, 1965/6, 1966/7, 1967/8, 1968/9.
Numerous papers in Scientific Journals, some specified in the text, most not.
Department of Physics Newsletters (ed. D.G.Davis) No. 1-7, June 1970-April 1971.
Report of the ad hoc Committee on the Resources Survey and Headship of the Dept of Physics & Astronomy; App. Executive Committee (D) 76/1/2.
Royal Society Obituary Notices:-
  George Carey Foster 1835-1919, A.H.Fison.
  Hugh Longbourne Callendar 1863-1930, S.W.J.S.
  Frederick Thomas Trouton 1863-1922, A.W.Porter.
  William Henry Bragg 1862-1942, E.N. da C. Andrade.
  Alfred William Porter 1863-1939, A.O.Rankine.
Royal Society Biographical Memoirs:-
  Edward Neville da Costa Andrade 1887-1971, A. Cottrell.
  Eric Henry Stoneley Burhop 1911-1980, Sir Harrie Massey & D.H.Davis.
  Harrie Stewart Wilson Massey 1908-1983, Sir David Bates, Sir Robert Boyd & D.G.Davis.

Other papers:-
Callendar, L.H. 1967: Professor H. L. Callendar, C.B.E., M.A., LL.D., F.R.S. (Life of father).
  Phys. Bull., April, 1961, 87-90.
Andrade, E.N. da C. 1966: A physics research student at Heidelberg in the old days.
  Physics Education, Vol.1, No.2, 69-78, July 1966.
Burhop, E.H.S. 1968: H.S.W.Massey - a sixtieth birthday tribute.
  Adv. Atomic Molec. Phys. 4, 1-11.
Bates, D.R. 1985: H.W.S.Massey, life, work, personality and characteristics.
  In 'Fundamental processes in atomic collision physics' (ed. H. Kleinpoppen)
  (Proc. NATO Summer School 1984) N.Y. Plenum Press.


Finally I must record my thanks to Michael Duff, who translated my manuscript into Word, and to John McKenzie, who has done all the work, including the insertion of the photographs, on including the document in the Departmental web site.