RSIC COMPUTER CODE PSR-020

1. NAME AND TITLE

LAPHANO: P_O Multigroup Photon Production Matrix and Source Vector Code for ENDF Data.

This code replaces LAPH.

AUXILIARY ROUTINES

Data should be preprocessed with CHECKER and with VIXEN to eliminate errors in format syntax and physical consistency.

2. CONTRIBUTOR

Los Alamos National Laboratory, Los Alamos, New Mexico.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; CDC 6600 or IBM 360.

4. NATURE OF PROBLEM SOLVED

LAPHANO retrieves photon production cross sections or multiplicities and corresponding neutron interaction cross sections from the ENDF/B data file, applies suitable weighting functions over G specified photon groups and N specified neutron broad groups, and constructs a G x N photon production matrix (microscopic and/or macroscopic). As an option, it operates on this matrix with flux vectors from a neutronics code, as well as with scalar multipliers such as atom number densities and effective photon group energies, to directly provide spatially dependent photon source vectors (number or energy) for transport calculations. Multiple zones can be accommodated, with separate cross-section weighting functions for each zone. Input is in the CCC-42/DTF-IV format and source vector output is also in this format, allowing direct coupling to DTF-IV. Complete freedom is allowed to pick those materials and reaction types for which photon production matrices are desired.

5. METHOD OF SOLUTION

LAPHANO first constructs photon production cross sections, pointwise in neutron and photon energy, from the ENDF/B data. These cross sections are then integrated over photon energy groups with either constant or direct energy weighting. After integrating over neutron energy in all neutron fine groups, weighting in neutron broad groups is by input fine-group weighting functions, usually the scalar fluxes from a fine-group neutronics calculation. Macroscopic photon production matrices and photon energy production matrices are then computed by scalar multiplication. Photon source vectors are computed by operating on these matrices with spatially dependent neutron flux vectors.

6. RESTRICTIONS OR LIMITATIONS

The microscopic pointwise data must be in ENDF format. The code is presently restricted to 99 fine or broad groups, 49 photon groups, and 50 mixture specifications.

7. TYPICAL RUNNING TIME

The central processor time on the CDC 6600 for a sample problem to produce a microscopic matrix for one material (oxygen) using 18 photon groups and 22 neutron fine and broad groups is approximately 18 seconds.

8. COMPUTER HARDWARE REQUIREMENTS

LAPHANO is operable on the CDC 6600 or the IBM 360 computers. The CDC 6600 requires 65 k₁₀ words of memory. One magnetic tape is required--the ENDF data tape is designated as tape 20. All other tapes are virtual tapes on disk, extended core storage, or other peripheral storage device.

9. COMPUTER SOFTWARE REQUIREMENTS

LAPHANO runs under the CDC SCOPE 3.1.2 System (locally modified) for the CDC 6600.

10. REFERENCES

a. Included in documentation:

D. J. Dudziak, R. E. Seamon, and D. V. Susco, "LAPHANO: A PO Multigroup Photon Production Matrix and Source Code for ENDF," LA-4750-MS (ENDF-156) (1971).

D. J. Dudziak, A. H. Marshall, and R. E. Seamon, "LAPH: A Multigroup Photon Production Matrix and Source Vector Code for ENDF/B," LA-4337 (1969).

b. Background information:

H. C. Honeck, "Retrieval Subroutines for the ENDF/B System," BNL-13582 (ENDF-110) (1967). (Revised CHECKER code by Oak Ridge National Laboratory, 1970).

D. J. Dudziak and J. M. Romero, "VIXEN, A Physical Consistency Checking Code for Photon Production Data in Revised ENDF Format," LA-4739 (1971).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents (10.a) and one (1.2MB) DOS diskette which contains the source code and sample problem input and output.

12. DATE OF ABSTRACT

September 1972; updated November 1983.