H scattering matrices

The elastic scattering formula of a neutron with a nucleus derived from the classical dynamics is used in some programs of slowing-down matrix calculation. The error arises from the formula for Hydrogen during the program execution because its mass is nearly equal to neutron's. So the special treatment is needed for the calculation of H matrices. Based on the new method presented by the author in 1978, the program GC-H composition has been completed on CYBER 825 computer.According to the dependence of H scattering cross section SIGMA(E) on neutron energy E in data file of US Evaluated Nuclear Data File ENDF/B-IV, all energy region (0-10.5 MeV) is divided into several sub-regions, and the lnSIGMA (E) is set to be linear with ln(E) in each sub-region, the difference of scattering cross section at any energy point between the treatment and ENDF/B-IV is enabled to be less than 1%. The H matrices are now calculated on CYBER 825 at a high speed with this program and the approach of data treatment mentioned above. For instance, the CPU time is about 4.06 secs with the code for the calculation of 63 g. H matrices (Legendre moments up to P1), but nearly 800 secs with the program FOURACES for the same case