A new fast-neutron source for radiobiological research

A biomedical cyclotron facility primarily dedicated to radionuclide production has been extended by the addition of an experimental fast-neutron source for radiobiological and biophysical studies. Several beams of fast-neutrons with different average energies and LET distributions can now be provided. The neutrons are produced by bombarding berryllium targets with 18-32 McV protons or 8.7-15 MeV deuterons from our K = 32 negative-ion cyclotron. Average neutron energies range from approximately 4 to 15 MeV. Doses at maximum build-up vary from 0.24 to 1.85 cGy microA-1 min-1 at 1 m SSD, i.e. approximately 55 cGy min-1 at 30 microA of proton current at maximum energy. The design of the facility and some dosimetric results are presented.