RSIC COMPUTER CODE PSR-011

1. NAME AND TITLE

POPOP4: Converter of Gamma-Ray Spectra to Secondary Gamma-Ray Production Cross Sections.

DATA LIBRARY

POPLIB: Library of gamma-ray production data.

2. CONTRIBUTOR

Computing Technology Center and Oak Ridge National Laboratory, Union Carbide Nuclear Division, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 360/75/91.

4. NATURE OF PROBLEM SOLVED

POPOP4 produces multigroup transfer cross sections for representing gamma-ray production due to neutron interactions. Any gamma-ray producing reaction (capture, inelastic scattering, etc.) can be represented as long as appropriate data describing the reaction is provided as input. Input can be from cards or a library tape. Two basic forms of data are allowed: gamma-ray production cross sections (barns) and yields (number of gamma rays per reaction). In the latter case the microscopic neutron cross sections for the given reaction are also required to convert the yields to gamma-ray production cross sections.

The output from POPOP4 then can be combined with output from codes that produce neutron-to-neutron group transfer cross sections (such as GAM-II and PSR-13/SUPERTOG) and gamma-ray to gamma-ray group transfer cross sections (such as CCC-42/GAMLEG and MUG) to produce a coupled set of cross sections. This coupled set can then be used in codes such as CCC-42/DTF-IV, CCC-82/ANISN-CEA, CCC-89/DOT, and CCC-127/MORSE to perform calculations which account for both neutron and secondary gamma-ray transport.

5. METHOD OF SOLUTION

In general, input data is specified for given neutron and gamma-ray group structures. Output is required for different group structures. Yield data is converted from the given structures to the required structures by multiplying by ratios proportional to mismatch between the given and required neutron and gamma-ray group structures.

Data in the form of yields are converted to production cross sections by multiplying by the microscopic neutron cross sections for the reaction. The neutron cross sections are usually taken from multigroup libraries.

6. RESTRICTIONS OR LIMITATIONS

The number of reactions which can be summed in one POPOP4 case is limited to 10.

7. TYPICAL RUNNING TIME

No study has been made by RSIC of typical running times for POPOP4.

8. COMPUTER HARDWARE REQUIREMENTS

POPOP4 is operable on the IBM 360/75/91 computers.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCES

a) Included in documentation:

W. E. Ford, III, and D. H. Wallace, "POPOP4, A Code for Converting Gamma-Ray Spectra to Secondary Gamma-Ray Production Cross Sections," CTC-12 (May 1969).

W. E. Ford, III, "The POPOP4 Library of Neutron-Induced Secondary Gamma-Ray yield and Cross Section Data," CTC-42 (1970).

b) Background Information:

W. E. Ford, III, and D. H. Wallace, "The Use and 'Testing' of Al, Fe, Ni, Cu, and Pb Secondary Gamma-Ray Production Data Sets from the POPOP4 Library," CTC-20 (July 1970).

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

November 1972; revised October 1983.

KEYWORDS: GAMMA-RAY PRODUCTION CROSS SECTION PROCESSING; MULTIGROUP CROSS SECTION PROCESSING