A new approach to single-comparator instrumental neutron activation analysis

A new parametric approach to single-comparator instrumental neutron activation analysis (INAA) at the University of Missouri Research Reactor (MURR) was investigated. A detailed MCNP steady-state model of the MURR core was developed using the latest neutron data libraries to compute the continuous-energy neutron flux distribution. Intrinsic reaction rates were predicted by coupling the computed local flux distribution to the isotopic (n, γ) excitation functions for a range of elements present in standard reference materials (SRM). Using the predicted (n, γ) reaction-rates, the concentrations for the various elements were determined. The method worked well for all nuclides tested, including those with cross sections that are not proportional to 1/v such as Lu and Eu with agreements for most elements within 5% of the reference value. (author)