Measurement of the ¹⁸O(α,n)²¹Ne Reaction Cross Section for Applications of Nuclear Science

Understanding the decay product spectra is crucial for passive interrogation of nuclear material. For low burnup fuels, (α,n) reactions on ^17,18O have been identified as a dominant source of neutrons. In the energy range of the α-decay of actinide elements, little data are available for the ¹⁸O(α,n)²¹Ne reaction, and it has been highlighted as a focus for experimental efforts. There is also interest in this reaction for other applications for nuclear physics. For example, in geochemistry, the production of ²¹Ne in Earth’s mantle provides insight into mantle processes. Existing data for this reaction are limited, with no partial cross section or neutron angular distribution data available. Therefore, a high-resolution measurement of the ¹⁸O(α,n)²¹Ne reaction was performed at the University of Notre Dame over the range E_α = 2-8 MeV, to extract partial and total cross sections. 10 ODeSA detectors were used for neutron spectroscopy, analyzed via the spectrum unfolding technique. In addition, 2 HPGe detectors were used to detect secondary γ rays. Partial differential cross sections for gamma and neutron channels and SCALE neutron source calculations using these data will be presented. Development of higher energy neutron detection systems for nonproliferation will also be presented.