High-pressure xenon ion chambers for gamma-ray spectroscopy in nuclear safeguards

There has been a long-standing need for a room-temperature gamma-ray detector system with high efficiency and adequate resolution for nuclear safeguards applications. For nuclear safeguards, measurements must resolve the uranium complex at 186 keV and the plutonium complex at 414 keV. The need for adequate room-temperature resolution has been met by CdZnTe detectors, but these small detectors cannot produce the efficiency needed for broad application in nuclear safeguards. The high-pressure xenon (HPXe) detector offers resolution, efficiency, intrinsic radiation resistance and temperature stability, making this detector type a viable candidate for broad application in nuclear safeguards. We will examine the current status HPXe detector systems, contrast HPXe with other detector types for nuclear safeguards applications, and discuss our efforts to improve the HPXe detector operating characteristics.