Evaluation of wavelength-dependent detection efficiency of neutron-sensitive microchannel plate detector

Abstract

The microchannel plate (MCP)/Timepix is one of the promising candidates for highperformance neutron imaging detectors. Since it is important to know the detection efficiency to plan experiments, we propose simple procedures to evaluate the wavelength-dependent detection efficiency of the MCP/Timepix detector. The wavelength-dependent efficiency curve can easily be evaluated by comparison with the neutron-induced prompt gamma-ray counts. The efficiency increases with the wavelength up to roughly 5 Å and eventually saturates. All neutrons with a wavelength of more than 5 Å are fully absorbed in the neutron-sensitive MCP. The activation effect in the MCP/Timepix detector is also investigated. We confirmed additional counts originating from the activation effect of aluminum, which was used in the detector entrance window. The contribution of the additional counts due to the detector activation was less than 10-4 compared with the neutron counts.