Novel method to improve neutron–gamma discrimination for boron-doped nMCPs

Energy-resolved neutron imaging has been a popular imaging method due to the progress of neutron sources and detection systems. Neutron-sensitive microchannel plate (nMCP) has been successfully used in various energy-resolved neutron imaging applications, thanks to their high spatial and temporal resolutions. However, neutron–gamma discrimination has been a critical challenge for nMCP detectors because of the high intrinsic gamma sensitivity. In the present time the methods to reduce the gamma influence for nMCP detector are mainly based on shielding or a coincidence scheme. In this paper, a novel method based on changing the gain and the content of nMCP materials is proposed to improve the neutron–gamma discrimination capability for boron-doped nMCPs. The influence of boron and lead concentration on the n/γ ratio is calculated by a simulation model. Results shows that the effect on the neutron–gamma​ discrimination of boron concentration is more significant than the lead concentration. In addition, it has been demonstrated by simulation and experiment that the neutron–gamma discrimination of nMCP could be improved by decreasing the gain. We found that as the nMCP voltage decreased, the relative n/γ ratio could be improved and the neutron loss could be reduced. These results confirm that the method is effective for improving nMCP neutron–gamma discrimination. In the future, the neutron–gamma discrimination will be further improved by optimizing the concentration of boron and lead as well as the working conditions for nMCPs and standard MCPs.