Performance of a gas target neutron source for radiotherapy

Abstract

The performance of a compact and efficient neutron generator, using the ³H(d,n) reaction and a gas target, is reported. The target is formed in a windowless, differentially pumped vessel pressurised to 7.5 Torr. An extended source of 15 MeV neutrons is produced when the target is bombarded by a 10 mA beam of 210 keV deuterons. Measurements are reported of the neutron energy spectra, neutron and gamma -ray dose rates, target lifetime and tritium handling. The neutron flux distribution of the extended target was measured and compared with the predictions of a simple beam-gas interaction model. The measured neutron source strength is 1.7+or-0.4*10¹² neutrons per second. The source output is limited by target beam current, not target power considerations.