Neutron absorption physics in the development and practice of activation analysis

The review outlines the contribution of neutron absorption physics toward the development and practice of neutron activation analysis techniques. In so far as they concern this development, fundamental nuclear parameters of neutron energy, absorption cross-section and induced nuclear interactions are briefly discussed. The basic analytical tools, such as the neutron source, sample irradiation and radiation measurement instrumentation, are described. In this respect, a special emphasis is placed on the utilization of essentially monoenergetic fast neutrons obtained from neutron generators for analytical applications. The role of activation techniques, in basic cross-section studies and in analytical chemistry, is discussed with a view to establishing the technique as a fundamental tool in nuclear physics research and materials characterization, respectively. The importance of neutron activation analysis is demonstrated by a critical comparison of its capabilities with those offered by competing chemical and other instrumental analytical methods. This comparison, in effect, provides an insight into the many areas where the contribution of neutron absorption physics has served in the development of a highly sensitive tool for trace analysis. The impact of neutron activation analysis in biological and biomedical studies, material science and industrial applications, environmental and ecological assessments, geo- and cosmo-chemical investigations, mineral and energy resource evaluations, and in archaeological and forensic sciences, is evidenced in the above areas of application. Some comments regarding the application of neutron activation analysis to future challenges in the realm of general materials characterization are offered. (author)