UC Berkeley

Detectors with microchannel plates (MCPs) are currently widely used in photon and charged particle detection with high spatial (similar to 10 um) 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 B-10 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 (nat)Gd2O3 is predicted to be only +/- 0.1 degrees and +/- 0.3 degrees 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.