A Weighted Point Model for the Thermal Neutron Multiplicity Assay of High-Mass Plutonium Samples

Krick, M.S. ; Geist, W.H. ; Mayo, D.R.

United States. Department of Energy. Office of Scientific and Technical Information.

关键词: Multiplicity;    Geometry;    Thermal Neutrons;    Simulation;    Neutrons;   

DOI  :  10.2172/876505
RP-ID  :  LA-14157
RP-ID  :  W-7405-ENG-36
RP-ID  :  876505

美国|英语

来源: UNT Digital Library

【 摘 要 】

A weighted point model for thermal neutron multiplicity counting has been developed for the assay of impure plutonium metal samples. Weighting factors are introduced for the spontaneous fission and ({alpha},n) contributions to the doubles and triples rates to account for the variations in neutron multiplication in these samples. The weighting factors are obtained from Monte Carlo simulations using the MCNPX code, which supports the simulation of spontaneous fission sources and can tally the source and detected neutron multiplicity distributions. Systematic behavior of the weighting factors was studied as a function of sample mass and geometry. Simulations were performed to evaluate the potential accuracy of assays performed with weighted point model analysis. Comparisons with experimental data are presented. The possible use of quads rates is explored.