In order to calculate coincidence correction factors when measuring with a low-energy photon detector (LEPD), algorithms were developed for the description of the summing-out probabilities taking into account -LX in addition to
-
and
-KX true-coincidences, where KX and LX can originate from internal conversion and electron capture. The accuracy of the calculation procedure is experimentally checked. The work presented here is part of an extension of the NAA k0-standardization to counting in a LEPD.