Neutron energy spectrum with microstructured semiconductor neutron detectors

Abstract

Microstructured semiconductor neutron detector (MSND) devices have achieved 42% intrinsic efficiency when operated as a dual-detector device. The neutron energy spectrometer has alternating layers of MSND arrays, cadmium, and high-density polyethylene (HDPE) in a linear arrangement. The detector arrays consist of 4 dual-detector devices with 1-cm2 detector elements in a stacked configuration. A 2 mm thick layer of cadmium separates each detector from the following layer of HDPE. The cadmium layer prevents thermalized neutrons from backscattering into the previous detector. The 3-cm thick HDPE layers act as a moderator for the epithermal and fast neutrons, allowing them to disperse energy within the spectrometer's volume and reach thermal energies to be detected by the MSND arrays. The resultant device is a neutron energy spectrometer with a large surface area for the incident neutron beam.