Coincidence summing corrections for the natural decay series in gamma-ray spectrometry

Using a Monte Carlo code and a Markov formalism to describe the decay schem es, coincidence-summing correction factors can be calculated with a suitabl e accuracy. For two different measuring geometries and an HPGe detector, ca lculated and experimental correction factors have been shown to closely agr ee for Eu-152. The simulation method has subsequently been applied in asses sing the need for coincidence-summing corrections for members of the uraniu m, thorium and actinium series measurable by gamma -spectrometry. Correctio n factors were calculated for predominant gamma emissions significantly aff ected by coincidence-summing effects and the correctness of our calculation s tested for environmental samples. The test makes it evident that in order to obtain reliable and unbiased activity values for some natural radionucl ides coincidence summing cannot be neglected in environmental measurements at small source-detector distances. (C) 2001 Elsevier Science Ltd. All righ ts reserved.