1. NAME AND TITLE OF DATA LIBRARY

AIRFEWG: Results of ANISN Multigroup Calculations of Gamma-Ray, Neutron, and Secondary Gamma-Ray Transport in Infinite Homogeneous Air Using DLC-31/(DPL-1/FEWG1) Cross Sections.

2. NAME AND TITLE OF DATA RETRIEVAL PROGRAM

EDT303: A program to edit the AIRFEWG data.

3. CONTRIBUTOR

Air Force Weapons Laboratory, Kirtland Air Force Base, New Mexico.

4. HISTORICAL BACKGROUND AND INFORMATION

Although many infinite homogeneous air calculations have been done, it was felt to be particularly useful to repeat them using a set of consistent and tested cross sections based on recently available sources.

Several years ago, the Defense Nuclear Agency developed a program of cross-section measurement and evaluation, integral data testing, and cross-section generation with the goal of providing its user community with multigroup cross sections adequate for the radiation transport calculations which they were required to perform. The evaluated cross-section library which was produced served as the basis for the generation of a few-group (37 neutron, 21 gamma-ray)) library using the AMPX cross-section processing system. The few-group library was tested for transport problems in air and concrete and packaged in RSIC as DLC-31/(DPL-1/FEWG1). Cross sections from FEWG1 were used to produce the AIRFEWG data.

5. APPLICATION OF THE DATA

DLC-49/AIRFEWG can be used to study the transport of gamma-ray, neutron, and secondary gamma-ray transport in infinite homogeneous air. Neutron and secondary fluences due to each of the 37 neutron source groups can be edited by the retrieval code. Gamma-ray fluences due to each of the 21 gamma-ray source groups can also be edited.

6. SOURCE AND SCOPE OF DATA

The one-dimensional discrete ordinates code ANISN was used to calculate neutron, neutron induced gamma-ray (secondary), and prompt gamma-ray scalar fluences. Group scalar fluences are included in AIRFEWG for 58 (37 neutron, 21 gamma-ray) energy groups at 18 range points from 50 to 7200 meters for neutrons and secondary gamma-rays, and at 17 range points from 50 to 6000 meters for prompt gamma-rays. Cross sections for nitrogen and oxygen from DLC-31/(DPL-1/FEWG1) were used in the calculation of radiation transport in 1.11 mg cc density air (79% vol. N, 21% vol. O). Both "1/E" weighted and "fission" weighted data sets from FEWG1 were used, the latter having been shown to predict transport for weapon fission sources with better accuracy at some ranges.

The results were generated with a P3 ANISN run with a source in a single energy group. Thus, 58 such runs were required. For sources in the 37 neutron groups, both neutron and secondary gamma-ray fluence results were calculated. For gamma-ray sources only gamma-ray fluences were calculated.

The retrieval code provides an edit capability. It could probably be extended to allow the user to calculate results for a particular source spectrum.

An empiric function was used to fit the results. Coefficients for the function are provided as part of AIRFEWG.

7. DISCUSSION OF THE DATA RETRIEVAL PROGRAM

The EDT303 program allows the user to edit data results for one or more source groups. Output is tabulated for all possible neutron groups and all secondary gamma-ray groups for each neutron source group. Results for each gamma-ray source group include output for all possible gamma-ray groups.

8. DATA FORMAT AND COMPUTER

BCD card images; IBM 360/91.

9. TYPICAL RUNNING TIME

To compile EDT303 and edit results from all 58 groups requires 1 minute on the IBM 360/91 computer.

10. REFERENCES

J. J. Burgio, "Gamma, Neutron, and Secondary Gamma Transport in Infinite Homogeneous Air," Vol. I, "Assumptions, Calculations, and Results," AFWL-TR-75-303 Vol. I (December 1975).

J. J. Burgio, "Gamma, Neutron, and Secondary Gamma Transport in Infinite Homogeneous Air," Vol. II, "Edited Results," AFWL-TR-75-0303, Vol. II (December 1975).

11. CONTENTS OF LIBRARY

Included are the referenced documents and one tape cartridge which contain data, EDT303 source, sample problem input and output, and coefficients for the empirical fit to the data.

12. DATE OF ABSTRACT

September 1977; updated December 1984.