Scintillation Detector for Neutron Flux Monitoring at the BNCT Facility

Abstract With the advent of new neutron sources for boron neutron capture therapy (BNCT) based on accelerators, it became necessary to create an independent system for monitoring the particle flux during patient irradiation. The results presented in this article showed that the proposed system based on a scintillator–optical fiber–silicon photomultiplier, using three different sensors, made it possible to measure the neutron flux, as well as to estimate the dose induced by gamma radiation. The use of two types of polystyrene scintillators: SC-301 and boron-enriched SC-331 manufactured by Logunov Institute for High Energy Physics (IHEP), National Research Center Kurchatov Institute, Protvino, makes it possible to estimate the contribution of neutrons, and the application of an additional sensor without a scintillator makes it possible to estimate the contribution to the signal from the Cherenkov radiation generated in the optical fiber. The implemented system for detecting optical signals based on silicon photomultipliers has a high quantum efficiency and the counting mode of operation of the readout electronics made it possible to achieve an intrinsic noise level of the order of several tens of hertz.