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Title: Covariances from light-element r-martix analyses

Abstract

We review the method for obtaining covariance information for light-element reactions using R-matrix theory. The general LANL R-matrix analysis code EDA provides accurate covariances for the resonance parameters at a solution due to the search algorithm it uses to find a local minimum of the chi-square surface. This information is used, together with analytically calculated sensitivity derivatives, in the first-order error propagation equation to obtain cross-section covariances for all reactions included in the analysis. Examples are given of the covariances obtained from the EDA analyses for n-p scattering and for the n+{sup 6}Li reactions used in the latest light-element standard cross section evaluation. Also discussed is a method of defining 'pure theory' correlations that could be useful for extensions to higher energies and heavier systems.

Authors:
 [1]
  1. Los Alamos National Laboratory
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
960468
Report Number(s):
LA-UR-08-04932; LA-UR-08-4932
TRN: US1002046
DOE Contract Number:
AC52-06NA25396
Resource Type:
Conference
Resource Relation:
Conference: Workshop on Neutron Cross Section Covariances ; June 24, 2008 ; Port Jefferson
Country of Publication:
United States
Language:
English
Subject:
73; ALGORITHMS; CORRELATIONS; CROSS SECTIONS; DATA COVARIANCES; EQUATIONS; ERRORS; EVALUATION; INFORMATION; LANL; NEUTRONS; R MATRIX; RESONANCE; SCATTERING; SENSITIVITY

Citation Formats

Hale, Gerald. Covariances from light-element r-martix analyses. United States: N. p., 2008. Web.
Hale, Gerald. Covariances from light-element r-martix analyses. United States.
Hale, Gerald. Tue . "Covariances from light-element r-martix analyses". United States. doi:. https://www.osti.gov/servlets/purl/960468.
@article{osti_960468,
title = {Covariances from light-element r-martix analyses},
author = {Hale, Gerald},
abstractNote = {We review the method for obtaining covariance information for light-element reactions using R-matrix theory. The general LANL R-matrix analysis code EDA provides accurate covariances for the resonance parameters at a solution due to the search algorithm it uses to find a local minimum of the chi-square surface. This information is used, together with analytically calculated sensitivity derivatives, in the first-order error propagation equation to obtain cross-section covariances for all reactions included in the analysis. Examples are given of the covariances obtained from the EDA analyses for n-p scattering and for the n+{sup 6}Li reactions used in the latest light-element standard cross section evaluation. Also discussed is a method of defining 'pure theory' correlations that could be useful for extensions to higher energies and heavier systems.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 2008},
month = {Tue Jan 01 00:00:00 EST 2008}
}

Conference:
Other availability
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