Preparation and characterizations of thallium bromide single crystal for room temperature radiation detector use

Thallium bromide (TlBr) crystal of 8-mm-diameter, preferentially oriented in [1 1 0] direction has been prepared using a melt-based method without mechanical vibrations. Analyses on the crystal quality and growth process were made based on characterizations of X-ray diffraction, rocking curve, ultraviolet absorption and transmittance spectrum. Most section of the crystal exhibits crystalline perfection and low stress, and its bandgap was calculated to be 2.88 eV. Influence of ampoule diameter on crystal quality has been discussed. Resistivity of the material was measured to be over 1010 Ω cm. Spectroscopic response of the fabricated detectors to 241Am shows 59.5 keV peak with the resolution of 38.27%.