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

Sources containing 75Se 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 75Se 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.