Baden — Betatrons for BBC

Abstract

In the spring of 1946, after my position in Norway had been sufficiently cleared up, I went to Switzerland and started on some preliminary work for a betatron. The construction drawings produced at that time were already pretty detailed. This was a machine with which electrons were going to reach energies of up to 31 MeV, which corresponds to an acceleration by 31 million volts. We had opted for 31 MeV because we wanted to extract the electrons out of the vacuum chamber, as we later in fact did. Electrons of 31 MeV penetrate about 10 cm of water — or the equivalent body tissue — and could therefore eventually exert the appropriate therapeutic effect. The machine was conceived first and foremost for such medical purposes.