Individual monitoring in mixed neutron/photon fields using a single silicon detector

A device based on a single silicon detector of special converter/detector design optimised for the determination of the neutron dose equivalent is also used for the determination of the photon dose equivalent. While the neutron dose is determined on the basis of signals corresponding to energy depositions above 1.5 MeV, depositions between 80 keV and 150 keV are used for the photon dose equivalent. In this way, a photon response is achieved which varies by less than 30% in the energy region from 80 keV to 7 MeV for irradiation at normal incidence and at 60 degrees to the normal. The lower limit of detection is of the order of 1 microSv. Neutrons contribute to the photon reading by less than 2% in mixed fields with a comparable dose equivalent from neutrons and photons.