Recent Progress in TlBr Radiation Detectors

Thallium bromide is a wide band gap, high Z, high density semiconductor that has been investigated as a nuclear radiation detector. In this paper we present experimental results on material purification, crystal growth, detector fabrication and detector characterization. TlBr material was purified by both distillation and zone refining. Crystals with 10-mm and 16-mm diameter were grown by the vertical Bridgman method. Single element devices and arrays were fabricated and tested. Mobility-lifetime products were found to increase as a result of purification. Potential applications of TlBr detectors are medical imaging and homeland security.