Improvement of energy resolutions in TlBr detectors

Improvement of energy resolutions in thallium bromide (TlBr) detectors was achieved by using a gated integrator in the post amplifier stage. An energy resolution of 4.8% FWHM at 662 keV was obtained from a TlBr detector 1 mm thick at room temperature. The depth of interaction (DOI) in TlBr detectors for incident gamma-rays was determined by taking the Gaussian shaping amplifier signal to gated integrator signal ratio. The energy resolution of the detector was improved from 4.8% to 3.8% FWHM by implementation of the depth correction. The device exhibited an energy resolution of 3.3% FWHM at 662 keV by selecting gamma-ray interaction events in the detector. Long-term stability of a TlBr detector 0.36 mm thick with Tl electrode was also evaluated at room temperature. The detector operated stably for 600 h without significant performance degradations.