Development and characterization of real-time personal neutron dosemeter with two silicon detectors

We have developed a new real-time personal neutron dosemeter containing two neutron sensors, a fast and a slow neutron sensor. The former sensor is a p-type silicon semiconductor detector. The slow neutron sensor is also a p-type silicon semiconductor detector and natural boron is doped on the aluminum electrode to produce 10B(n,α) reactions. A thin polyethylene radiator is contacted on the front surface of each sensor to produce recoil protons. 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 the two sensors, the detection efficiency could be made to approach to the fluence-to-dose equivalent conversion factor given by ICRP 51. Field tests of the performance of this neutron dosemeter were performed in the radiation environments around several nuclear facilities, including reactor, accelerator, radioisotope and nuclear fuel handling facilities. Based on the results of these field tests, we conclude that our dosemeter is able to provide a reading of the neutron dose equivalent within a factor of 2 margin of accuracy.