LiGlass, LiI(Eu), and CLYC: A Shootout to Obtain the 6Li(n,a) Cross Section

Leo Kirsch, University of California, Berkeley

The next generation of nuclear reactors will use lithium salts to moderate the neutron economy. Monte Carlo computer codes need lithium cross section data to predict the sensitive neutron multiplication factor for given reactor geometries. The lithium cross section evaluations contain discrepancies among the databases at high energy far from the 250 keV resonance. On-site engineers at research reactors currently tweak cross section values to match the reactor environment seen by the neutron monitors. There will be one less parameter to tune with an accurate assessment of the lithium cross section making the future of nuclear energy more reliable.

An experiment at Los Alamos National Laboratory's Lujan Center is collecting data on the 6Li(n,α) cross section using LiGlass, LiI(Eu) and CLYC detectors aimed at a 252Cf spontaneous fission neutron source. Each detector brings a host of advantages to the experiment, with trade-offs between detection efficiency, particle discrimination and timing resolution. The data acquisition system will collect months worth of statistics, enough to resolve the features in the lithium cross section in the high-energy region.

Abstract Author(s): L. Kirsch, M. Devlin, S. Mosby, J. Gomez