RBE values of d (16) + Be and d (50) + Be neutrons for chromosome rearrangements induced in mouse spermatogonia.

The rate of reciprocal translocations induced in mouse spermatogonia by exposure to X-rays and to neutrons produced by 16 and 50 MeV deuterons has been estimated by scoring multivalent configurations in the descendant spermatocytes. In the X-irradiated group the yield of translocations increases from 2,1 per 100 cells after exposure to 100 rad to 5,7 after exposure to 300 rad. The dose-response relationship shows no statistical departure from linearity. After exposure to 50, 100 or 150 rad of d (16) + Be and d (50) + Be neutrons, the yield of translocations displays a humped curve. Up to this dose the RBE value decreases with absorbed dose and neutron energy.