1. NAME AND TITLE OF DATA LIBRARY

NOX: 199-Group, P₅, Coupled Neutron and Secondary Gamma-Ray Cross Section Data for Nitrogen and Oxygen.

2. NAME AND TITLE OF DATA RETRIEVAL PROGRAM

No retrieval program is included in the package.

3. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

4. HISTORICAL BACKGROUND AND INFORMATION

The cross-section data in DLC-17/NOX were compiled at ORNL to be used for studies of neutron and secondary gamma-ray transport in nitrogen and air. The data library was preserved since it was based on new evaluations for N and O and since results using the data have been reported. The nitrogen data were used in a calculation study of gamma-ray production and transport in liquid nitrogen which compared results with experiments in liquid nitrogen. Results of several ORNL studies using the nitrogen and oxygen data were presented to assess the adequacy of the nitrogen cross sections.

5. APPLICATION OF THE DATA

DLC-17/NOX is suitable for multigroup neutron, gamma-ray, or coupled neutron and gamma-ray transport calculations in nitrogen, oxygen, or air. The retrieval program manipulates the data so that it can be used in codes such as CCC-82/ANISN-CEA, CCC-89/DOT, or CCC-127/MORSE.

6. SOURCE AND SCOPE OF DATA

The coupled 86 neutron and 33 gamma-ray energy group cross sections were produced by members of the ORNL Mathematics Division. The neutron multigroup data were produced with PSR-13/SUPERTOG, the neutron to gamma-ray group transfer matrices with a modified version of NUSECT, and the gamma-ray multigroup data with MUG. NUSECT is the cross section generator for CCC-128/O6R, but modifications had to be made to the version in the RSIC code package to generate the desired gamma-ray production matrices.

This data represents a P5 Legendre expansion approximation for neutron elastic scattering and gamma-ray Compton scattering. Inelastic neutron scatter and gamma-ray production are treated as isotropic.

Cross section values for the neutron thermal group (86) were determined by assuming a Maxwellian weighting function with a constant scattering cross section and a "1/v" absorption cross section.

The 86 neutron groups cover the energy range from 15 MeV to thermal and the group structure was chosen to represent the variation in the nitrogen total cross section. The 33 gamma-ray groups span the energy range from 10 to 0.01 MeV. The gamma-ray group structure was chosen with one group of width 0.02 MeV containing each nitrogen resolved line and one group of varying energy width between adjacent resolved lines.

The neutron interaction secondary gamma-ray production and gamma-ray interaction multigroup data were generated from recent evaluations by Young and Foster. The evaluations are part of the DNA Working Cross Section Library and the identification designations are DNA MAT 4133, MOD 1 for nitrogen and DNA MAT 4134, MOD 0 for oxygen. These are available from RSIC upon request.

7. DISCUSSION OF THE DATA RETRIEVAL PROGRAM

Not applicable.

8. DATA FORMAT COMPUTER

BCD/EBCDIC card images; IBM 360/370.

9. TYPICAL RUNNING TIME

To read the NOX data from a card image tape and rewrite it on an unformatted tape required 14 seconds on the IBM 360/91 computer.

10. REFERENCES

a. Included in the documentation:

E. A. Straker and B. J. McGregor, "A Calculation of Gamma-Ray Production and Transport in Liquid Nitrogen," ORNL-TM-3635 (December 1971).

"LIBGEN: A Special Version of the ANISN Library Generation Routine which Converts a Card Image FIDO Format Cross Section Tape into an Unformatted ANISN Library Tape."

G. M. Reynolds and S. M. Sperling, "A Re-analysis of Secondary Gamma-Ray Spectra Produced in Liquid Nitrogen by 14 MeV Neutrons," DNA 2831F, SAI-71-550-LJ (March 1972).

b. Background information:

P. G. Young and D. G. Foster, Jr., "An Evaluation of the Neutron and Secondary Gamma-Ray Production Cross Sections for Nitrogen," LA-4725 (1972).

P. G. Young and D. G. Foster, Jr., "An Evaluation of the Neutron and Secondary Gamma-Ray Production Cross Sections for Oxygen," LA-4780 (1972).

R. W. Roussin, "The Defense Nuclear Agency Working Cross Section Library: Description and Contents," ORNL-RSIC-34 (1972).

11. CONTENTS OF LIBRARY

Included are the referenced documents (10.a) and one (1.2MB) DOS diskette which contains the cross section data, library routine source code and sample problem input, plus output from the library routine.

12. DATE OF ABSTRACT

August 1972; revised May 1984.