Probability correction for the analytical simulation approach to calibrating γ-ray cylindrical detectors for environmental measurements

Marinelli beakers increase geometric efficiency of detection in the γ-spectrometry of low-activity environmental samples by positioning the sample in close proximity to the detector. A probability correction has been introduced to the analytical simulation approach proposed previously (Nafee et al., 2009) for calculating detection efficiencies of γ-ray cylindrical detectors using extended low- and high-volume Marinelli beakers. Improved expressions for the self-attenuation and the coincidence summing effects at short source-detector distances have also been included in the analytical algorithm. A remarkable agreement between the measured and calculated efficiencies was observed as a result. Deviations of results calculated in this way from experimental values are twice as small as were observed with the previously reported analytical methods (Abbas, 2001; Nafee et al., 2009).