Analysis of Position-Sensitive Capacitive Frisch-Grid TlBr Detectors

This work presents results from analyzing position-sensitive capacitive Frisch-grid (PS-CFG) TlBr gamma-ray detectors. As a room-temperature semiconductor detector, TlBr exhibits a high atomic number, high density, and low Fano factor compared to other material. The use of the 3D position sensing technique provides information on the crystal uniformity. This technique presents the spatial variation in the histograms of the anode amplitude versus the cathode-to-anode ratio, necessary for depth correction, for detectors fabricated with 5×5×12 mm ³ TlBr crystals at room temperature operating at continuous bias (1.5 kV) over the course of nine months. This work also presents the temperature dependence of the leakage current for a TlBr PS-CFG detector over the temperature range of -20 to +60 °C, which varies from <0.2 to 40 nA, respectively, along with changes in the spectrum from the anode signal measured with ¹³⁷ Cs irradiation. This work shows the utility of the 3D technique to evaluate the performance and uniformity of PS-CFG detectors for applications that require high-energy resolution gamma-ray spectroscopy, such as radionuclide identification.