TlBr capacitive frisch grid detectors

Capacitive Frisch grid detectors with the dimensions of 2 mm\,\times\,2 mm\,\times\,4.4 mm were fabricated from TlBr crystals grown by the travelling molten zone method using zone-purified materials. Spectroscopic performance of the detectors was evaluated at room temperature (24^\circ C), {-} 5^\circ C and {-} 20^\circ C. The TlBr detector exhibited an energy resolution of 1.6% FWHM at 662 keV with a peak-to-Compton ratio of 8.7 with the depth correction at room temperature. Improvement of the detector performance was achieved by cooling the detector-preamplifier system. The energy resolutions of 3.4%, 1.5%, 1.0% and 0.9% FWHM at 122 keV, 356 keV, 662 keV and 1332 keV, respectively, were recorded with the TlBr detector without the depth correction at {-} 5^\circ C. An energy resolution of 0.9% FWHM at 662 keV with a peak-to-Compton ratio of 18.2 was obtained from the TlBr detector with the depth correction at {-}20^\circC. An upper limit for the Fano factor of TlBr was estimated to be 0.43 at {-}20^\circC.