Performance Test of the Electronic Personal Neutron Dosemeter in Neutron Fields Simulating Workplaces of MOX Fuel Fabrication Facilities

Recently, several electronic personal dosemeters (EPDs) capable of measuring neutron dose equivalents were developed and have appeared on the market. The authors initiated the present study to assess performance of neutron EPDs. The EPD selected for this study was NRY21, manufactured by Fuji Electric Systems Co., Ltd. This dosemeter uses two silicon semiconductor detectors (a fast neutron sensor and a thermal neutron sensor) to provide wide measurable energy ranges from thermal to several tens of MeV. In the test, we focused on the energy and angular dependences of dose equivalent responses because they were of great importance in neutron dosimetry in work environments. Measurements of dose equivalent responses were performed in a moderated neutron field simulating neutron spectra likely to be encountered in workplaces at MOX fuel facilities. As a result, the dose equivalent responses of this EPD were evaluated to be 0.7 to 1.1 for a normal incidence of neutron irradiation. This is a satisfactory performance for neutron monitoring.