出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The production of dicentric chromosomes in human lymphocytes by high-energy neutron
radiation was studied at the neutron beam facility of iThemba Laboratory using a quasimonoenergetic
192 MeV neutron beam. The linear yield coefficient of the linear dose-response
relationship for dicentric chromosomes was measured to be (0.096 ± 0.020) Gy-1. This confirms
our earlier observations that the yield of dicentric chromosomes decreases with increasing
neutron energy above 400 keV and is almost constant above 20 MeV. Using the linear-quadratic
dose-response relationship for dicentric chromosomes established in blood of the same donor for
60Co g-rays as reference radiation, an average maximum low-dose RBE (RBEM) of 9 ± 3 for 192
MeV quasi-monoenergetic neutrons, with a dose-weighted average energy of 162.1 MeV, was
obtained. The yield of chromosome aberrations due to neutrons from the low-energy breakup
continuum of the quasi-monoenergetic neutron spectrum was determined by an additional
measurement at a neutron emission angle of 16° where the high-energy peak is strongly
suppressed. Using this technique, a yield coefficient a = (0.121 ± 0.026) Gy-1 and an RBEM of
12 ± 4 for virtually monoenergtic 192 MeV neutrons was determined. The increased
uncertainties result from the application of the (0°-16°) difference method.
