Characterisation of a Real-time Personal Neutron Dosemeter with Two Silicon Detectors

Abstract

A new real-time personal neutron dosemeter has been developed. The dosemeter contains two neutron sensors, a fast neutron sensor and a slow neutron sensor, which are both p-type silicon semiconductor detectors contacted with two different radiators of polyethylene and boron. The neutron detection efficiencies of these sensors were measured in a thermal neutron field and monoenergetic neutron fields from 8 keV to 22 MeV. By taking the weighted sum of counts given by two sensors, the detection efficiency could be approached to the fluence-to-dose equivalent conversion factor given by ICRP 74. The field tests of the performance of this neutron dosemeter were carried out in the radiation environments around several nuclear facilities; reactor, accelerator, radioisotope and nuclear fuel handling facilities. Based on the results of these field tests, the dosemeter is able to provide a reading of the neutron dose equivalent within a factor of 2 margin of accuracy.