Fast Neutron Detector Registration System

Abstract

With the appearance of accelerator-based neutron sources for Boron Neutron Capture Therapy (BNCT), the need arose for an independent system to measure the generated particle flux. For this purpose, Budker Institute of Nuclear Physics (Siberian Branch, Russian Academy of Sciences) developed a fast neutron detector based on a scintillator–optical fiber–silicon photomultiplier detection system. It utilizes three different sensors, allowing for the measurement of neutron flux as well as the estimation of the local dose induced by gamma radiation. The optical signal-detection system based on silicon photomultipliers possesses high quantum efficiency, and the use of a pulse-counting mode for event registration made it possible to achieve an intrinsic noise level of approximately several tens of counts per second. Furthermore, the counting characteristic of the readout electronics is well described by a nonextendable dead time of 24.6 ± 0.1 ns, which allows for the registration of events with minimal miscounting even under high detector load.