A comparison of heavy water and beryllium as cyclotron targets for fast neutron production for radiotherapeutic applications

Fast neutron central axis depth doses and spectra produced by bombarding beryllium and heavy water targets with 16 and 10 MeV deuterons have been measured. In addition estimates of the dose-rates at 100 cm from the two targets for various deuteron energies in the range 8–16 MeV have been made. It is shown that a heavy water target may be useful at 10 MeV with the smaller “compact” cyclotrons as a source of neutrons for radiotherapy.