Analysis of large and non-standard geometry samples by internal mono standard INAA method based on in-situ detection efficiency

摘要

A ko-based internal mono standard instrumental neutron activation analysis (INAA) method for determination of relative elemental concentration in samples of large size and irregular geometry has been developed. In this method, one of the elements present in the sample is used as comparator. The problems of gamma ray self-attenuation and geometrical effects that arise in the assay of large and non-standard geometry samples were overcome by an in-situ relative detection efficiency calibration procedure, which requires one or more activation products emitting gamma rays over a wide range of the spectrum. To minimize the problem of neutron flux perturbations that may arise in large samples, irradiations were carried out using a thermal column with thermal component of 99.98 percent.