Calendar: 1974-1975 Page 466

Annual Report of the Delegacy lxxxv Conference at Daresbury With Dr Barr he organised King's College stand at the Institute of Physics Exhibition at which two advanced teaching experiments were shown one on the determination of the velocity of light and the other on teaching photo-electron spectrometer Professor Domb gave invited lectures at the Royal Radar Establish- ment Malvern Weizmann Institute Israel Hebrew University Israel National Bureau of Standards Temple University Chapel Hill North Carolina Yeshiva University Brookhaven National Laboratory Summer School on Molecular Physics Leeds Nobel Symposium on Collective Properties of Physical Systems Sweden The University of Rhodesia was visited by Professor Wilkinson where he lectured and examined He also lectured to the Summer School at Leeds and the Solid State Physics Conference Manchester Current research by Dr Lightowlers Dr Collins and Dr Davies involves studies of point defects in diamond by optical absorption cathodoluminescence and photoluminescence measure- ments Their investigations are mainly concerned with defects produced by irradiation damage and their interaction with impurities recent development has been the measurement of luminescence decay times down to 10 second with pulsed electron beam This type of measurement has yielded valuable information on energy transfer processes between luminescence centres and defects which provide non-radiative decay path Charged particle techniques using the accelerators at Harwell are being employed for the deter- mination of light element impurity concentrations in GaP and diamond Of major interest at present are oxygen and nitrogen in GaP and boron in diamond and it is proposed that these measurements should be extended to an investigation of oxygen in GaAs and InP The nuclear group under Dr Griffiths have completed their col- laborative work with Queen Mary College using the Harwell Synchro- cyclotron and proposals for continuing the work using the new 'mesonfactory' accelerator at Vancouver are being considered The study of complex reactions proceeding via two-step mechanisms is continuing under Dr Edwards' guidance Several sets of complete data on the entrance and exit channels of the reactions are now available and analysis with the theories developed by the group are in progress The scattering of helium and helium beams from the Harwell