A compact MPPC-based camera for omnidirectional (4π) fast-neutron imaging based on double neutron-proton elastic scattering

摘要

Neutron localization, which finds (localizes) neutron sources, is a non-destructive method used in the application of nuclear emergency response and special nuclear material (SNM) localization. Fast neutrons from SNM fission can be detected using a hydrogen-rich scintillation detector system with relatively high efficiency. In this study, we proposed a compact multi-pixel photon counter (MPPC)-based neutron scattering camera prototype consisting of sixteen plastic scintillator pillars. This camera is capable of detecting fast neutrons produced by neutron sources in the far-field. It provides a three-dimensional structure to detect incident neutrons with omnidirectional (4 pi) field-of-view. Based on double neutron-proton elastic scattering, a reconstructed image can be achieved by using an Am-Be source. Besides, time-of-flight technology was adopted for separating neutron signals from the gamma-ray background radiation. The results of the imaging efficiency and the average imaging resolution are reported in this article. This camera offers good prospects to expand the application field of SNM localization for nuclear security and proliferation deterrence.