Relative genetic efficiency of chronic fast neutrons and gamma rays in mice

Chromosome aberrations following spermatogonjal irradiation were studied in mice exposed to fast neutrons or gamma rays at similar dose rates, 80 +- 20 mrad/hour, and doses ranging from 10 to 442 rad. The mean energy of neutrons from a plutonium-berrylium source was 4,1 MeV while the radium gamma rays had a wide energy spectrum. For each radiation dose, yields of reciprocal translocations were ascertained by cytogenetic analysis carried out three to four months after treatment on primary spermatocytes at diakinesis-metaphase I of meiosis. Dose-response relationships are presented graphically and analytically for both radiation types. Relative genetic efficiency estimated from the linear portion of the dose-response curve was found to equal 10. (author)