Purification and preparation of TlBr crystal for room temperature radiation detector applications

Thallium bromide (TlBr) is a compound semiconductor with a high atomic number and wide band gap, being a very promising material to be used as room temperature radiation detectors. In this work, the commercial TlBr powder was used for growing crystals for detector applications. To reduce impurities, this material was purified by the zone refining technique. Trace impurities at ppb/ppm level were analysed using ICP-MS. The efficiency of the purification was evaluated through studies of the decrease impurities concentrations in the TlBr powder and in the materials purified. The crystal quality was verified by DRX. To evaluate the crystal as a semiconductor detector, systematic measurements of the transmittance, resistivity and the radiation response of (²⁴¹Am, ⁵⁷Co and ¹³³Ba) gamma rays were carried out.