Neutron Dosimetry with Ion Chamber-Based DIS System

INTRODUCTION A new type of personal dosimeter has been developed by RADOS Technology Oy. This system is based on a novel detector type, an ionisation chamber with so-called Direct Ion Storage (DIS). Ionisation chambers are sensitive to both neutrons and photons. Therefore, the application of the DIS principle to neutron dosimetry requires a double-chamber system for separating photon from neutron dose components. A chamber with the highest-possible and a chamber with the lowest-possible neutron sensitivity must be used, and their signals have to be differentiated. The energy dependences for photons of the two chamber types have to be almost equal to obtain good photon discrimination.