Efficiency of 7.62 cm bismuth germanate scintillators

We present the experimentally determined intrinsic photopeak efficiencies for bismuth germanate scintillator 7.62 cm in diameter and 7.62 cm in length over the energy range 0.1-5.0 MeV. We studied eight detectors individually with point sources at 30.8, 61.3, 91.7, and 152.7 cm from the crystal; two additional detectors, for a total of 10, were studied with sources at 61.3 and 91.7 cm. We present intrinsic photopeak efficiency curves, determined by averaging the data from all detectors and fitting the results at each of the four distances. (orig.)