Thallium bromide optical and radiation detectors for X- and gamma-ray spectroscopy

Compound semiconductor, thallium bromide (TlBr), has been investigated as an optical and radiation detector material for use in X- and /spl gamma/-ray spectroscopy. Single crystals of TlBr have been grown by the traveling molten zone method using zone-purified materials. Direct X- and /spl gamma/-ray detectors have been fabricated from the TlBr crystals. The direct TlBr detectors have exhibited good spectrometric performances at room temperature. Polarization in TlBr detectors has been observed to deteriorate detector performance. Optical detectors for scintillation spectroscopy have been fabricated from the crystals by depositing an optically transparent electrode of indium-tin-oxide (ITO) on the front surface of the crystals. Quantum efficiency of the TlBr optical detectors has been high in wavelength region below /spl sim/460 nm where scintillation emissions of LSO and GSO occur.