36a HardCell: A Robust Sensor Head for Hot Cell Nuclear Material Accounting and Control

Nuclear energy could contribute to solving the climate crisis by displacing power generation from fossil fuels. U.S. domestic nuclear material accounting and control (NMAC) for emerging nuclear fuel cycles require new innovative nuclear detector technologies that include advanced scintillators and readout electronics for gamma spectroscopy in an inert hot cell environment. These detectors must retain both gamma-ray and neutron sensitivity in a high radiation, high temperature environment. The HardCell sensor head to be developed in this project is a radiation hard and temperature resistant nuclear detector using an advanced scintillation material coupled to a rugged photomultiplier tube interfaced to an active voltage divider network and first stage amplifier. A promising scintillation material is praseodymium bromide (PrBr3), which has a density of 5.3 g/cc, and a decay time of 9 ns. Early samples have shown light yields of 20 photons/keV and energy resolution of 5.6% full width at half maximum (FWHM) at 662 keV. High-temperature, radiation-tolerant readout electronics consisting of an active voltage divider and first stage amplifier will be coupled to a robust photomultiplier tube to provide good signal fidelity at high rates. The Phase 1 effort will target PrBr3 at the primary candidate scintillator for the sensor head to be evaluated at temperature and under exposure. A prototype amplifier and voltage divider circuit will be characterized, as components will be analyzed as a function of dose and temperature. The sensor head is a key technology element for both gamma ray spectroscopy and neutron detection. The technology development provides a framework from which a variety of form factors can be obtained for a myriad of nuclear material accounting and control applications. The technology developed within this project facilitates products used in extreme environments, such as sensors for space missions.