A NEW FAST-NEUTRON SOURCE FOR RADIOBIOLOGICAL RESEARCH

A biomedical cyclotron facility primarily dedicated to radionuclide pr oduction has been extended by the addition of an experimental fast-neu tron source for radiobiological and biophysical studies. Several beams of fast-neutrons with different average energies and LET distribution s can now be provided. The neutrons are produced by bombarding berryll ium targets with 18-32 MeV protons or 8.7-15 MeV deuterons from our K = 32 negative-ion cyclotron. Average neutron energies range from appro ximately 4 to 15 MeV. Doses at maximum build-up vary from 0.24 to 1.85 cGy mu A(-1) min(-1) at m SSD, i.e. approximately 55 cGy min(-1) at 3 0 mu A of proton current at maximum energy. The design of the facility and some dosimetric results are presented.