The efficiency of thermal neutron detection and collimation with microchannel plates of square and circular geometry

Abstract

Detectors with microchannel plates (MCPs) are currently widely used in photon and charged particle detection with high spatial (/spl sim/10 /spl mu/m) and temporal (<0.5 ns) resolution. All the advances in MCP detection technologies can be successfully implemented for the detection of thermal neutrons by using MCPs manufactured from a modified glass mixture doped with neutron absorbing atoms. In this paper, we compare the efficiency of thermal neutron detection for two standard MCP geometries: circular-pore and square-pore MCPs doped with the /sup 10/B isotope. The results of our modeling indicate that the detection of thermal neutrons with a square-pore MCP is 11%-23% more efficient than for the circular geometry, and can be higher than 70% for the existing MCP technology. The same MCPs can be used as very efficient and compact thermal neutron collimators. In this paper, we compare the efficiency of circular- and square-pore MCP collimators with the help of our model, the validity of which has already been verified by our experimental measurements reported last year. The rocking curve of 5-mm and 2.5-mm thick MCPs doped with 3 mole % of /sup nat/Gd/sub 2/O/sub 3/ is predicted to be only /spl plusmn/0.1/spl deg/ and /spl plusmn/0.3/spl deg/ wide, respectively, for both geometries. A very compact device with high thermal neutron detection efficiency and angular sensitivity can be built by combining an MCP neutron detector with an MCP collimator.