Thallium bromide photodetectors for scintillation detection

A wide bandgap compound semiconductor, TlBr, has been in investigated as a blue sensitive photodetector material for scintillation detection. The TlBr photodetectors have been fabricated from the TlBr crystals grown by the TM Z method using materials purified by many pass zone refining. The performan ce of the photodetectors has been evaluated by measuring their leakage curr ent, quantum efficiency, spatial uniformity, direct X-ray detection and sci ntillation detection characteristics. The photodetectors have shown high qu antum efficiency for the blue wavelength region and high spatial uniformity for their optical response. In addition, good direct X-ray detection chara cteristics with an energy resolution of 4.5 keV FWHM for 22 keV X-rays from a Cd-109 radioactive source have been obtained. Detection of blue scintill ation from GSO and LSO scintillators irradiated with a Na-22 radioactive so urce has been done successfully by using the photodetectors at room tempera ture. A clear full-energy peak for 511keV gamma-rays has been obtained with the TlBr photodetector coupled to the LSO scintillator with an energy reso lution of 40% FWHM, (C) 2000 Elsevier Science B.V. All rights reserved.