抄録
Neutron, one of indirectly ionizing radiation, gives dose to substances in a very complicated manner. Dose deposition profile for neutrons depends significantly on the size of substance as well as incident energy. In the neutron dosimetry in radiation effect study, it is important to understand how neutrons transport in the material, what kind of secondary radiations or charged particles neutrons produce, and how these charged particles deposit their energy into the substance, in addition to the information of incident neutron energy. As an example, while recoiled protons give major absorbed dose in the incidence of neutrons above 100 keV, electrons due to gamma-rays produced by the capture reaction of hydrogen nucleus contribute to more than 90% of human absorbed dose in the incident of neutrons less than 10 keV. This means that the dose deposition profile for low-energy neutrons in the human body has a very similar aspect for gamma-ray exposure. It can be said from these facts that some detailed analysis of dose deposition profile by using computer simulation techniques should play an important role in biological effect study for neutron. [J Radiat Res 44:373 (2003)]
