Relation between the activity of a high-density waste drum and its gamma count rate measured with an unshielded Ge-detector

The activity A of a waste drum homogeneously filled with waste and y emitters is calculated from the peak count rate Z of an unshielded Ge-detector after a point source efficiency calibration. The activity calculation is confirmed at various distances (50–200 cm) and by comparison with other activity determinations. The accuracy is within the range of the calibrating standards. The formula covers different measuring distances, matrix compositions, densities and γ-ray energies.