Abstract
Radiation weighting factor of low-energy neutron is an operational quantity inferred from the LET-RBE convention of charged particles and still remains highly conceptual. Currently, experimental data on chromosomal effectiveness of neutrons with different energy have been accumulated, including those of our filtered spectrum neutrons. The dose-response relationships of chromosome aberrations in the in vitro-irradiated human peripheral blood lymphocytes indicates that the quality factors are consistent with the those inferred from the LET-RBE convention for the monoenergetic neutrons in the energy range above 1 MeV, that is inversely proportional to neutron energy. However, there is little energy dependency for lower energy neutrons over a wide mean energy range down to 20 keV, their effective quality factors being stayed at high value similar to those of fission neutrons or thermal neutrons. This comes up to a serious problem that the effective quality factor or radiation weighting factor of low energy spectrum neutrons are not a simple sum of the currently proposed energy-dependent radiation weighting factors. A possible reasoning for the discrepancy will be discussed. [J Radiat Res 44:373 (2003)]
