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

A 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. X- and /spl gamma/-ray detectors have been fabricated from the TlBr crystals. The 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 optically transparent electrodes of indium-tin-oxide (ITO) on the front surfaces of the crystals. The quantum efficiency of the TlBr optical detectors is high in the wavelength region below /spl sim/460 nm, where the scintillation emissions of LSO and GSO occur.