Roy Middleton, Emeritus Professor of Physics at the University of Pennsylvania, died at home on June 23, 2004 at the age of 77 after a prolonged illness. We will summarize his immense and important contributions to the fields of experimental nuclear physics, the cesium sputter negative ion source, discovering new techniques and applications of AMS, and the study of atomic and molecular physics of negative ions.
Roy received his Ph.D in 1951 from Liverpool University where he pioneered research on (d,n) stripping reactions using 8 MeV deuterons with thick photographic emulsion plates, which had considerable impact on the development of the collective model. He continued his nuclear studies at AWRE Aldermaston (UK) from 1955-1963, where he performed numerous pioneering experiments such as the transfer reaction 9Be(t,p)11Be, which gave the wrong shell model parity to the ground state of 11Be.
Roy became Professor of Physics at the University of Pennsylvania in 1965 where he continued his love for nuclear physics using the multigap detector. In 1972 he turned his brilliant technical abilities to the design and development of the Cs negative ion sputter ion source, which resulted not only in the critical step that propelled AMS forward, but which also enabled new nuclear reaction studies. In 1979 he was awarded the prestigious Tom W. Bonner Prize of the APS for his work on ion sources. The culmination of this work resulted in his remarkable "Negative ion Cookbook" that reports beam intensities for atomic and molecular negative ions obtained from almost every element.
His work on applications of AMS covered a wide variety of fields and he maintained numerous collaborations throughout USA and Europe. Together with colleagues at the Carnegie Institution in Washington, he demonstrated using 10Be detected in lavas in island-arc volcanoes that subducted mid-ocean sediments were recycled on timescales of millions of years.
Collaborations with LANL, Rutgers, and Scripps resulted in expanding the understanding of solar and galactic cosmic ray interactions with extraterrestrial materials. He pioneered an ambitious program to test the potential of 41Ca AMS to date Pleistocene bones. He constructed the first 14C CO2 gas ion-source, the 17O5+ continuous monitoring method for 10Be, new chemical preparation methods for CaH2, and 40CaDH beam monitoring for 41Ca.
In his final years Roy worked on negative atomic and molecular anions and dianions, including the detection of N2-, CO2-, and N3-, . These extensive experimental works are now often quoted by theoretical chemists.
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See more of The 10th International Conference on Accelerator Mass Spectrometry (September 5-10, 2005)