Development of integrated-type dosimeter responsive to high energy neutrons (1)

The response of plastic nuclear track detectors to high-energy neutron has been investigated as a personnel dosimeter for radiation protection in a field observed around particle accelerators and at high altitudes. At first, three types of detectors, pure CR-39, TD-1 (containing an antioxidant) and TNF-1 (co-polymer of CR-39 and NIPAAm) were compared after exposure to quasi-monoenergetic neutrons generated by p-Li reactions at TIARA, JAERI. TD-1 detector was selected as a most promising element from viewpoints of the detection efficiency and post-etched surface. In the second, the radiator effect has been investigated both experimentally and theoretically for more efficient detection of high-energy neutrons. A performance of four types of radiator materials, CH2, CD2 (deuterized hydrocarbon), LiF and C, was checked. The efficiency has also been numerically calculated based on a model with a special attention to the angular dependence of cross sections and data of characteristic response to light ions. The effect of respective radiator candidates has been evaluated as a function of the neutron energy. A two-layer radiator has been proposed to adjust the energy dependence of the relative sensitivity to conversion factor for dose-equivalent. (author)