Accession Number : AD0685704

Title :   EXTENDING THE NEAREX STATISTICAL MODEL NUCLEAR CROSS-SECTION CODE TO SIMULTANEOUS (np) (n-Gamma) REACTIONS,

Corporate Author : RAND CORP SANTA MONICA CALIF

Personal Author(s) : Green,J. M. ; Hubbard,H. W. ; Bloom,S. D.

Report Date : MAR 1969

Pagination or Media Count : 28

Abstract : A description, with source deck listing and flow charts, of four improvements made to the Argonne National Laboratories' ABACUS-NEAREX program for computing nuclear cross-sections for neutron scattering problems. NEAREX uses the Hauser-Feschbach calculation scheme and the optical potential model. A problem that caused machine overflow when protons of very low kinetic energy were involved was solved by setting the transmission coefficient to zero, thus avoiding the wave function calculation. (This is a reasonable approximation when the Gamow penetration factor is extremely small.) The original code set the neutron mass equal to 1; the exact value is now used, with necessary changes in the reduced mass correction. Other changes involve resetting certain variables to zero before each of successive computer runs, and properly restoring the optical well parameters when the original code fails to make such a restitution in part of the gamma computation. (Author)

Descriptors :   (*NEUTRON CROSS SECTIONS, COMPUTER PROGRAMS), NUCLEAR REACTORS, NEUTRON TRANSPORT THEORY, NEUTRON SCATTERING, FLOW CHARTING, POTENTIAL THEORY, PENETRATION, GAMMA NEUTRON REACTIONS

Subject Categories : Computer Programming and Software
      Fission Reactor Physics
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE