Digital gamma-gamma coincidence measurements for neutron activation analysis

The ability to perform low level counting, specifically gamma spectroscopy, for unknown radionuclides provides some challenges. In many cases, the ability to assess a material requires the use of neutron activation analysis (NAA) to excite the unknown sample to allow for the use of gamma ray measurement techniques to determine the radionuclides that are present. Quite often, the ability to identify unique gamma rays is challenging due to the fact that many radionuclides have gamma rays that have energies that are nearby other gamma rays from other radionuclides. The Compton continuum and high background radiation levels also contribute to the difficulty to make these measurements. This research has explored the use of an advanced digital gamma-gamma coincidence system, XIA Pixie-16, for use in neutron activation analysis. The reason for performing this research is that, although gamma-gamma coincidence in NAA is not a new area of research, there has not been a comprehensive study of the use of gamma-gamma coincidence for all NAA products. This research has the potential to benefit research and experiments that utilize NAA techniques for identifying unknown samples. The new XIA Pixie-16 system was first assembled and characterized. It was then used to perform measurements for all applicable short-lived, medium-lived and long-lived NAA products. The gamma-gamma coincidence system was utilized to identify radionuclides in different samples that have been demonstrated to be difficult to identify using standard gamma spectroscopy techniques. A thorough evaluation of the results of this research should serve as a reference for all future NAA research.