Show description

In the language of Equation (11), each such sub-subsection of covariance information corresponds to an evaluated uncertainty component cov (X,Y') i the subscript is omitted above for simplicity. n There is an invalid but acceptable approximation in the definition that the files represent covariances between cross-sections at specific energy points, because the uncertainty in a point cross-section generally will be very large unless smoothness versus neutron energy can be guaranteed on physical grounds.

W. PEELLE this framework, experimental results are considered to be drawn from hypothetical populations of potential experiments performed with the same experimental uncertainties; and if inherent bias is assumed absent, the mean of each such population would be a true value. Performed experiments have constituted a small sample from these populations; each equivalent set of experimental results that could just as well have occurred to constitute our present data base would have led to a member of the ensemble of evaluated results.

All of the correlation patterns given in Table II are susceptible to simple processing to the extent that a supergroup (ultrafine group structure) representation is adequate to define the energy dependence of the flux. One must generally add to the set of ultrafine-group energy delimiters the set of all the uncertainty data energy boundaries that occur anywhere in the File 33 for a given material. * If this set * Unfortunately, the required set of added energies implicitly includes those in any standard cross-section referred to through any NC-type subsection.