Influence of crystalline surfaces on the TlBr radiation detector performance

Thallium bromide (TlBr) is an important material for room temperature detectors. Due to its high photoelectric absorption efficiency and large band gap, thallium bromide is a good candidate for X- and gamma-ray spectrometry. In this study, TlBr detectors were fabricated from the crystals purified by the multipass zone refining and grown by the Bridgman method. Detectors were prepared using TlBr wafers of about 0.3 mm thick, with surface submitted at different mechanical and chemical treatments. The results of surface quality of TlBr wafers, evaluated by scanning electron microscopy, are presented. Spectrometric performance of the TlBr detector was assessed by excitation with ²⁴¹Am gamma-ray source at room temperature. The dependence of the radiation on the detector was affected by the condition of the crystalline surface. This study has important implications for adequate processing of TlBr surfaces for radiation detector applications