Douglas Allen undertook studies at the University of Adelaide (BSc1935) and was Rhodes Scholar in 1937, studying at New College, Oxford, graduating with a DPhil in Nuclear Physics in 1941. During WWII he served for 3 years as scientific officer at the Telecommunications Research Establishment (UK). In 1944 he was transferred to the United States and worked on the Manhattan Project at Berkeley, California, specialising in isotope separation.
Dr Allen was Research Physicist at the Atomic Research Establishment, Hartwell, UK from 1946-1961, where he measured fast fission (neutron) cross sections of various heavy isotopes, involving the use of electrostatic accelerators. His work led to important improvements to accelerating tubes. From 1966-1977 Douglas Allen was senior member and division head at the Rutherford High Energy Laboratory (UK). Following retirement he was part time professor of Engineering at the University of Reading, a visiting professor at the University of the West Indies (Barbados), and the University of Southampton, which honoured him with an HonDSc in 1984.