Abstract–Neutron multiplicity counters are used in safeguards to provide rapid assay of samples which contain an unknown amount of plutonium in a potentially unknown configuration. A project at PNNL is using regular and nickel-quenched 6LiF/ZnS neutron-scintillator sheets and wavelength shifting plastic for light pipes in place of 3He. A combination of laboratory and modeling work predicts a LiF/ZnS-based system to be able to match or exceed the performance of the best 3He-based systems available. Also, the Ni-quenched material is expected to allow for improved neutron/gamma-ray discrimination at twice the event rate relative to the non-Ni-quenched LiF/ZnS. A new system based on the LiF/ZnS material is under construction and components are being used to optimize the detection efficiency and neutron/gamma-ray discrimination properties. Components of the new system are partially constructed and undergoing performance testing utilizing high-speed digitizers with field programmable gate arrays to perform the neutron/gamma-ray discrimination. The expected performance of the full-scale system is expected to be nearly the same as for 3He-based systems and is due for completion in 2016.
Revised: December 2, 2016 |
Published: October 6, 2016
Citation
Stave S.C., R.S. Behling, B.E. Bernacki, M. Bliss, C.C. Cowles, R.T. Kouzes, and A. Lintereur, et al. 2016.Development of a 6LiF/ZnS-based Neutron Multiplicity Counter. In IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2015), October 31-November 7, 2015. Piscataway, New Jersey:IEEE.PNNL-SA-114809.doi:10.1109/NSSMIC.2015.7581917