Thallium bromide (TlBr) is a semiconductor compound with a high atomic number and a wide bandgap, being a very promising material to be used as room temperature radiation detectors. In this work, 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 analyzed using inductively coupled plasma mass spectroscopy (ICP-MS). The efficiency of the purification was evaluated through studies of the decrease impurities concentrations in the TlBr powder and in the purified materials. The crystal quality was verified by X-ray diffraction (XRD). To evaluate the crystal as a semiconductor detector, systematic measurements of the transmittance, resistivity, and the radiation response ( 241 Am, 57 Co, 125 I, and 133 Ba) gamma rays were carried out.

Thallium bromide is a semiconductor compound with high atomic number and density. It has a CsCl-type simple cubic crystal structure and it is non-hygroscopics. The TlBr crystals are relatively soft with a knoop hardness number of 12. In this work, the TlBr commercial powder was purified by zone refining and the purest material section was used for crystal growth by Bridgman method. Efforts have been concentrated on the purification of the TlBr. The purification efficiency has been evaluated (NAA and ICP-MS) by impurities reduction results after zone refining passes. The crystalline quality was evaluated by X-ray diffraction. The characterized TlBr crystal as a detector has shown good response to gamma radiation.

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