TRUE-COINCIDENCE CORRECTION WHEN USING AN LEPD FOR THE DETERMINATION OF THE LANTHANIDES IN THE ENVIRONMENT VIA K-0-BASED INAA

As part of a recent study on the environmental effects caused by the o peration of a coal-fired power station at Sines, Portugal, k(0)-based instrumental neutron activation analysis (INAA) was used for the deter mination of the lanthanides (and also of tantalum and uranium) in plan t leaves and lichens. in view of the accuracy and sensitivity of the d eterminations, it was advantageous to make use of a low-energy photon detector (LEPD). To begin with, in the present article, a survey is gi ven of the former developments leading to user-friendly procedures for detection efficiency calibration of the LEPD and for correction for t rue-coincidence (cascade summing) effects. As a continuation of this, computer coincidence correction factors are now tabulated for the rele vant low-energetic gamma-rays of the analytically interesting lanthani de, tantalum, and uranium radionuclides. Also the 140.5-keV line of Mo -99/Tc-99m is included, molybdenum being the comparator chosen when co unting using an LEPD.