Energy Dependent Bias in the Weighted Point Model.
Abstract
While the weighted point multiplicity model has successfully reduced the bias that is associated with variable multiplication of neutrons within a sample (which was assumed constant in the standard point multiplicity model), other potential sources of bias still exists within the weighted point model. One significant source of bias arises from the assumption that the energies of the neutrons from ({alpha},n) reactions on impurities in the sample have the same average energy as neutrons emitted from the spontaneous fission of {sup 240}Pu. An investigation into the effects that neutron energy has on the assay results (effective {sup 240}Pu mass, alpha, and multiplication) of the weighted point multiplicity model has been performed using MCNPX, Version 2.5f for impure plutonium metal samples in a number of different detector systems. The effects of energy dependence of the detection efficiency and gate fractions on the assay results, as well as the measured singles, doubles, and triples rates were also studied. Methods for mitigating the effects of neutron energy on the weightedpoint multiplicity model results will be presented and discussed.
 Authors:

 Peter A.
 William H.
 Publication Date:
 Research Org.:
 Los Alamos National Laboratory
 Sponsoring Org.:
 USDOE
 OSTI Identifier:
 977983
 Report Number(s):
 LAUR054287
TRN: US1003776
 Resource Type:
 Conference
 Resource Relation:
 Conference: Institute of Nuclear Materials Management 46th Annual Meeting, July 1014, 2005, Phoenix, Arizona
 Country of Publication:
 United States
 Language:
 English
 Subject:
 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; DETECTION; EFFICIENCY; ENERGY DEPENDENCE; IMPURITIES; MULTIPLICITY; NEUTRONS; NUCLEAR MATERIALS MANAGEMENT; PLUTONIUM; SPONTANEOUS FISSION
Citation Formats
Santi, P A, and Geist, W H. Energy Dependent Bias in the Weighted Point Model.. United States: N. p., 2005.
Web.
Santi, P A, & Geist, W H. Energy Dependent Bias in the Weighted Point Model.. United States.
Santi, P A, and Geist, W H. Sat .
"Energy Dependent Bias in the Weighted Point Model.". United States. https://www.osti.gov/servlets/purl/977983.
@article{osti_977983,
title = {Energy Dependent Bias in the Weighted Point Model.},
author = {Santi, P A and Geist, W H},
abstractNote = {While the weighted point multiplicity model has successfully reduced the bias that is associated with variable multiplication of neutrons within a sample (which was assumed constant in the standard point multiplicity model), other potential sources of bias still exists within the weighted point model. One significant source of bias arises from the assumption that the energies of the neutrons from ({alpha},n) reactions on impurities in the sample have the same average energy as neutrons emitted from the spontaneous fission of {sup 240}Pu. An investigation into the effects that neutron energy has on the assay results (effective {sup 240}Pu mass, alpha, and multiplication) of the weighted point multiplicity model has been performed using MCNPX, Version 2.5f for impure plutonium metal samples in a number of different detector systems. The effects of energy dependence of the detection efficiency and gate fractions on the assay results, as well as the measured singles, doubles, and triples rates were also studied. Methods for mitigating the effects of neutron energy on the weightedpoint multiplicity model results will be presented and discussed.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2005},
month = {1}
}