Improved low power, modular thermal neutron counter based on microstructured semiconductor neutron detectors (MSND)

Abstract

A modular, mass-producible, low-power, compact thermal-neutron counter has been developed to meet the needs for modern detector instruments and to compete with aging 3He-based counter systems. The Domino™ V5.4 neutron detector package is populated with four 1-cm2 active-area microstructured semiconductor neutron detectors (MSNDs). The detectors are calibrated to an intrinsic thermal neutron detection efficiency of 30% over its 4 cm2 active area. A gamma-ray rejection ratio of at least 1:10”8 is achieved at this calibration level. Total device dimensions measure 2.5-cm wide by 3.8-cm tall and 0.47-cm thick, weighing 9.5 g. Individual Dominoes™ can be tiled together into strings and then arrayed laterally to form large-area instruments. In this form, the small sensor can populate instruments up to 1 m2, with a cost that is comparable to a similar 3He-based array. The addition of I2C-based bias and threshold controllers reduces sensor cost and complexity over the previously-reported Domino™ versions (V3.0 and V4.0) and allows for user-end calibrations and modifications. Furthermore, the Domino™ has realized 10× reduced power consumption over previous versions, to nearly 90μW at 3.3 volts, while also reducing sensitivity to thermal- and capacitance-induced noise from the MSNDs, making the Domino™ an ideal candidate for 3He replacement and implementation in low-power, portable neutron-detector instruments.