SOME ALGORITHMS FOR THE NUCLEAR DATA EVALUATION AND THE COVARIANCE MATRIXES OF UNCERTAINTIES CONSTRUCTION

Authors & Affiliations

Gay E.V.
Russian Federation State Scientific Centre — A.I. Leipunsky Institute of Physics and Power Engineering, Obninsk, Russia

Abstract

The nuclear data evaluation is performed with use of realistic covariance matrix of observable uncertainties of the experimental data. This matrix is built on the base of the model of piecewise constant energy dependence of the experimental uncertainties. The use of this model makes it possible in the process of LSM solution to go without inversion of ill-conditioned matrix with rank, equal to full number of the experimental points and to invert matrix with rank, equal to number of energy zones of the mentioned above piecewise constant function. In the frame of traditional LSM the problem of the joint processing of already known estimates and the new experimental data is considered. The algorithm for construction of the covariance matrixes of the uncertainties of the different reactions multigroup cross-sections, correlated because of the use of the same reference cross-sections in the relative measurements, is described

Keywords
covariance matrix of the errors, model piecewise constant dependence, multigroup assessments sections, correlation support of section

Article Text (in Russian, PDF)

References

UDC 539.17

Problems of Atomic Science and Technology. Series: Nuclear Constants", issue 1-2, 2007