Performance tests of a large volume cerium tribromide (CeBr₃) scintillation detector

The response of a large cylindrical 76 mm×76 mm (height×diameter) cerium tribromide (CeBr₃) detector was measured for prompt gamma rays. The total intrinsic activity of the CeBr₃ detector, which was measured over 0.33-3.33 MeV range, was found to be 0.022±0.001 counts/s/cm³. The partial intrinsic activity ( due to ²²⁷Ac contamination), was measured over a energy range of 1.22-2.20 MeV energy, was found to be 0.007±0.001 counts/s/cm³. Compared to intrinsic activities of LaBr₃:Ce and LaCl₃:Ce detectors of equivalent volume, the CeBr₃ detector has 7-8 times less total intrinsic activity.The detector response for low energy prompt gamma rays was measured over 0.3-0.6 MeV gamma energy range using a portable neutron generator-based Prompt Gamma Neutron Activation Analysis (PGNAA) setup. The experimental yield of boron, cadmium and mercury prompt gamma-rays was measured from water samples contaminated with 0.75-2.5 wt% mercury, 0.31-2.50 wt% boron, and 0.0625-0.500 wt% cadmium, respectively. An excellent agreement has been observed between the calculated and experimental yields of the gamma rays. Also minimum detection limit (MDC) of the CeBr3 detector was measured for boron, cadmium and mercury samples. The CeBr₃ detector has 23% smaller value of MDC_B and 18% larger value of MDC_Cd than those of a LaB_r3:Ce detector of equivalent size.This study has shown that CeBr₃ detector has an excellent response for the low energy prompt gamma-rays with almost an order of magnitude low intrinsic activity as compared to LaCl₃:Ce and LaBr₃:Ce detectors of equivalent volume.