Coincidence-summing in gamma-ray spectrometry by excitation of matrix X-rays

Sources containing Se-75 in a Pb(NO3)(2) solution and in water matrices were measured using a well-type and a coaxial HPGe detector. The excitation and detection of characteristic lead X-rays increase coincidence losses from the peaks of Se-75 in the case of the Pb(NO3)(2) source. Sum peaks between gamma-rays of selenium and lead X-rays are observed in the spectra. The experimental results are in accordance with results of computations carried out with an extension of the GESPECOR Monte Carlo program. (C) 2000 Elsevier Science Ltd. All rights reserved.