Factors affecting performance of the micro-layered fast-neutron detector

The Micro-Layered Fast-Neutron Detector (MLFD) is a proton-recoil scintillation detector constituting microscale alternating layers of hydrogenous medium and ZnS:Ag. The device employs a peripheral photon detection for maximizing light collection while minimizing gamma-ray background. The layered configuration offers several novel advantages inherently by design, e.g., it overcomes the light-opacity limitation of polycrystalline ZnS, recoil protons have a high probability of reacting with the scintillation grains in their forward-directional path, the design and photomultiplier orientation eliminates the need for extraneous light guides, and minimizes Ĉerenkov generation and collection. The most striking ability of the MLFD is that its efficiency can be scaled higher by simply adding layers and increasing the length, up to 20 cm. Presently, a 40-mm MLFD has an intrinsic detection efficiency of 9.2% for bare 252Cf. Described is a comparison between experimental results and a theoretical model, the respective performances of which differ in high energy regions. The differences in the two models suggest that epoxy in the MLFD contributes to an increased count rate in higher channels.