Efficiency calibration of a HPGe detector in the [46.54-2000] keV energy range for the measurement of environmental samples

Here we describe a general method of calibrating the efficiency of a Ge gam ma -ray spectrometer. The method, which is based on the work of Quintana an d Fernandez (Appl. Radiat. Isot. 47 (1996) 911), can now be applied to many different experimental set-ups including both liquid and solid environment al samples, The method requires two different types of experimental inputs. Firstly, it requires measurements with radioactive sources emitting cascad es of gamma rays covering the energy range of interest. Secondly, it requir es measurements with sources emitting isolated gamma rays in order to provi de coincidence-summing corrections. On this basis, we establish a general f unction to describe the energy dependence of the efficiency for the particu lar geometry and source matrix. The method has been applied to 11 different experimental arrangements to provide efficiency calibrations over the rang e 46.54-2000 keV with associated uncertainties ranging from 0.1% to 1.8%. T his allows high precision measurements with environmental samples, which of ten have very low activities. (C) 2001 Elsevier Science B.V. All rights res erved.