A new summing-correction method for gamma-efficiency calibration with multi-gamma-ray radionuclides

Coincidence-summing effects play an important role in HPGe spectrometry at low source-to-detector distances (usual arrangements when environmental samples have to be measured). Although these corrections are not important for environmental samples (less than 5%), they can be significant in the efficiency calibration with multi-gamma-ray radioisotopes as they have to be measured in the same geometry. In this paper we propose a new method for determining summing corrections which does not require other monoenergetic radioisotopes. Thus, a HPGe-detector-efficiency calibration can be performed with radionuclides emitting gamma rays in cascade, such as 152Eu or 226Ra. The method has been successfully validated.