Comparison of IUPAC k 0 values and neutron cross sections to determine a self-consistent set of data for neutron activation analysis

Abstract

Abstract Independent databases of nuclear constants for Neutron Activation Analysis (NAA) have been independently maintained by the physics and chemistry communities for many year. They contain thermal neturon cross sections σ 0, standardization values k 0, and transition probabilities P γ . Chemistry databases tend to rely upon direct measurements of the nuclear constants k 0 and P γ which are often published in chemistry journals while the physics databases typically include evaluated σ 0 and P γ data from a variety of experiments published mainly in physics journals. The IAEA/LBNL Evaluated Gamma-ray Activation File (EGAF) also contains prompt and delayed γ-ray cross sections σ γ from Prompt Gamma-ray Activation Analysis (PGAA) measurements that can also be used to determine k 0 and σ 0 values. As a result several independent databases of fundamental constants for NAA have evolved containing slightly different and sometimes discrepant results. An IAEA CRP for a Reference Database for Neutron Activation Analysis was established to compare these databases and investigate the possibilitiy of producing a self-consistent set of σ 0, k 0, σ γ , and P γ values for NAA and other applications. Preliminary results of this IAEA CRP comparison are given in this paper.