A proton accelerator in Trondheim in the 1930s

Abstract

ABSTRACT: Johan Holtsmark at the Norwegian Institute of Technology (N.T.H.) in Trondheim, Norway, built a Van de Graaff generator for nuclear disintegration between 1933 and 1937. This is believed to be the second Van de Graaff generator in Europe and the first particle accelerator in Scandinavia. Holtsmark's successful project followed the failed attempt at N.T.H. by Olaf Devik in the 1920s to develop a discharge tube for nuclear disintegration driven by an evacuated Tesla coil. The genesis of Holtsmark's project was the interaction with Odd Dahl, who had constructed a Van de Graaff accelerator at the Department of Terrestrial Magnetism, Carnegie Institution of Washington. Holtsmark approached organizations potentially interested in cancer research and treatment for financial support. The electrical engineers appointed to build several parts of the accelerator had been radio amateurs, like many accelerator pioneers at the time. The team had to construct almost everything themselves given financial constraints and the lack of a supporting electrical industry. When operative in 1937, the Van de Graaff generator was already a comparatively small machine. The Trondheim scientists chose to develop it as a precision machine for proton capturing experiments in light elements. The accelerator proved a useful tool for research and teaching until 1963, when it was shut down and given to the Norwegian Museum of Science and Technology. This article seeks to answer why Holtsmark engaged in such an ambitious project in the periphery of Europe's scientific community and how he succeeded at a small department with several coexisting research activities.