Use of Neutron Scintillation Detectors as a Substitute for Helium-3 Counters in Radiation Monitors

Аннотация

The purpose of this work is to analyze the use of detecting materials in radiation monitors as well as the replacement of widely used ³H-based neutron counters by neutron-detection scintillation technology. The replacement of helium counters is a consequence of two factors: the lack of ³He and widespread use of ³He-based counters in safety equipment, such as volumetric neutron detectors. Selection criteria for evaluating promising technologies are used in this work, specifically, high absolute neutron detection efficiency – efficiency at least 1.5 counts in 1 sec in detecting 1 ng ²⁵²Cf at distance of 2 m in a 20 mm thick moderator and low sensitivity to γ-ray detection – γ-ray detection efficiency not exceeding 10^–6 with irradiation by a 0.1 μSv/h γ-ray source. Since they can have a large sensitive area and high resolution, scintillation detectors are now being proposed as alternatives to helium counters. But it is necessary to find an optimal scintillator possessing simultaneously low sensitivity to γ-radiation and to choose an optimal method of measuring information. Promising neutron detection technologies based on the glasses Li₂OSiO₂:Ce³⁺, LiF/ZnS(Ag⁺), Li₆Gd(BO₃)₃:Ce, Cs₂LiYCl₆(Ce) (CLYC) as well as EJ-254 boron-doped plastic are examined from the standpoint of the posed problems.