Investigation on the Performance of Dosimeters for Individual Monitoring Applications at the O-arai Engineering Center

An investigation on the performance of various dosimeters to be used for individual monitoring at the O-arai Engineering Center (OEC) was executed. The present TLD system was compared with recently produced dosimeters, such as OSL, Glass dosimeter, EPD and SSTD. The practical use of these dosimeters was also taken into account. There were no problems for any of the dosimeters for γ-ray individual monitoring. The OSL and glass dosimeters, which have good characteristics for γ-ray, can be used in various radiation environments without correction. On the other hand, the conversion factor is needed for low-energy γ-ray dosimetory when using EPD or TLD. None of the individual neutron dosimeters' responses relative to the neutron dose are adequate. Respective dose corrections according to the field conditions should be applied to the dosimeter outputs. The directional dependence of the relative response of EPD and SSTD are significant, and attention should be paid to the directional distribution of incident neutrons when using EPD or SSTD. The operational characteristics of each dosimeter were discussed, such as batch processing availability, robustness, fading characteristic, and reusability. As the result of the investigation, EPD was found to be the best γ-ray individual dosimeter for OEC applications, because of its flexibility in operation. On the other hand, the best neutron dosimeter for OEC is the TLD because of the low directional dependence of response.