Neutron/gamma scintillation detector for status monitoring of accelerator-driven neutron source IREN

Abstract

This paper presents a neutron/gamma detector based on a micropixel avalanche photodiode and a plastic scintillator that monitors the status of the accelerator-driven intense resonance neutron source (IREN) facility by measuring the neutron/gamma intensity in the target hall. The electronics of the neutron/gamma detector has been designed and developed. The size of the plastic scintillator was selected to be 3.7 × 3.7 × 30 mm3 due to the sensitive area of the MAPD. The experimental results demonstrated a dependence between the count rate of the detector and the frequency of the accelerator. The detector is sensitive to intermediate and fast neutrons. The minimum detectable energy was determined to be 200 keV using Cs-137 point gamma source. The maximum counting rate of the detector from TTL out is about 2.2·106 counts/sec, but for analogue output it is about 2·107 counts/sec. The detector can not allow discriminating neutrons and gamma rays by charge integration method.