Modification of the SUPERTOG Program Applied to Libraries with Tabulated Elastic-Scattering Anisotropy Densities

摘要

In calculating the matrix for intergroup elastic-scattering transitions by the SUPERTOG program, it is necessary that the data on the anisotropy of the elastic scattering be given in terms of the coefficients for a Legendre polynomial expansion of the density function. However, for all the material in the ENDL library and for some of the material in ENDF/B-IV, the information on the scattering anisotropy is given in the form of tabulated values of the actual density function. Existing versions of the SUPERTOG program cannot be used for these materials. We have developed a modification of the SUPERTOG program which enables us to calculate the elastic-scattering matrix whichever of the two ways the anisotropy is given. With this method, which is based on an approximation by means of orthonormal polynomials, it is possible to calculate the coefficients in the Legendre polynomial expansion of the density function during the operation of the actual program. In fact, this procedure takes less than 15% of the total running time of SUPERTOG. (Atomindex citation 13:680839)