Quantitative Investigation of Room-Temperature Breakdown Effects in Pixelated TlBr Detectors

Abstract—Due to favorable material properties such as high atomic number (Tl: 81, Br: 35), high density ( g/cm), and a wide band gap (2.68 eV), thallium-bromide (TlBr) is currently under investigation for use as an alternative room-temperature semiconductor gamma-ray spectrometer. TlBr detectors can achieve less than 1 % FWHM energy resolution at 662 keV, but these results are limited to stable operation at. After days to months of room-temperature operation, ionic conduction causes these devices to fail. This work correlates the varying leakage current with alpha-particle and gamma-ray spectroscopic per-formances at various operating temperatures. Depth-dependent photopeak centroids exhibit time-dependent transient behavior, which indicates trapping sites form near the anode surface during room-temperature operation. After refabrication, similar perfor-mance and functionality of failed detectors returned. Index Terms—Alternative room temperature semiconductor, TlBr spectrometers. I