Dr W.D. Allen, an innovative nuclear physicist and engineer always known as Doug, was recognised as an outstanding figure in the British development of large electrostatic accelerators. Born in Mussoorie, India in 1914 his early life was as part of a South Australian Methodist mission based at Azamgarh, near Varanasi. Returning with his parents to Adelaide he attended Prince Alfred's College and, subsequently, Adelaide University. A man of many talents he also studied piano at the Elder Conservatorium and played hockey for Australia against India at Melbourne in 1935.
Awarded a Rhodes Scholarship for South Australia in 1937 he was a member of New College, Oxford and was awarded a D.Phil in nuclear physics from the Clarendon Laboratory in 1940. Doug married Genevieve Thomson, also from Adelaide, in November 1939 in St James's church Muswell Hill, London. In the war he worked initially with the pioneering radar establishment at Swanage, and then at TRE Malvern, before moving to Berkeley, California, to work on uranium isotope separation. After a brief return to Australia he was invited in 1946 back to the UK to join the Nuclear Physics Division at AERE, Harwell. Jointly with the unrelated K.W. Allen he led the team that designed and built the Aldermaston and Harwell tandem Van de Graaff accelerators. The Harwell machine began operating only months after the world's first tandem, built by Van de Graaff's company for the Canadian Chalk River Laboratory, and remained a valuable resource for over forty years.
In 1961 Allen transferred with the Accelerator Division to the new Rutherford Laboratory near Harwell to lead the group charged with designing and installing the coupled electrostatic accelerators for the new Nuclear Physics Laboratory in Oxford. His patent for improved accelerator tubes was the basis for tubes used in Van de Graaffs in five continents. He also invented the Laddertron, a charging system for electrostatic machines adopted, among others, by the designers of the large national tandem at Daresbury. He remained at the Rutherford Laboratory until 1977, simultaneously holding a Visiting Professorship in the Engineering Department ar Reading. He was also a Visiting Professor at the University of the West Indies (1978-9) and at Southampton (1978-81) where he receivedan honorary D.Sc. in 1884.
He remained active as a cathedral guide, in parish affairs and in musical activities in Abingdon and Oxford. His wife, Genevieve, predeceased him by three months. He is survived by four children and by thirteen grandchildren and greatgrandchildren.
