Efficiency calibration and simulation of a LaBr3(Ce) detector in close‐geometry

Close‐geometry efficiency calibration has been performed for a 25.4 mm×25.4 mm cylindrical LaBr3(Ce) detector using calibrated point sources of 137Cs and 60Co placed on the top of the detector surface. The absolute total detection efficiency and the absolute photo-peak efficiency, obtained with 60Co, are corrected for coincidence-summing effect. The measured efficiency for 137Cs and the corrected efficiencies for 60Co are reproduced by GEANT4 simulations, considering the detector in a realistic geometry. In addition, the simulations also faithfully reproduce the entire measured spectra for both the sources.