1. NAME AND TITLE OF DATA LIBRARY

SIGMA-A: Photon Interaction and Absorption Cross Sections.

2. NAME AND TITLE OF DATA RETRIEVAL PROGRAMS

RANDOM: Sequential-to-Direct Access Conversion Program.

READX: Cross Section Table Retrieval Program.

3. CONTRIBUTOR

Ontario Cancer Institute, Toronto, Ontario, Canada.

4. HISTORICAL BACKGROUND AND INFORMATION

An extensive library of photon interaction coefficients has been developed by the Ontario Cancer Institute, Toronto, Ontario, Canada, based on the compilation of Plechaty, Cullen, and Howerton.² In addition to partial cross section data, the following are given: mass attenuation coefficients, mass energy transfer coefficients, mass energy absorption coefficients, average energy transferred to electrons, average energy absorbed per interaction, and average stopping power of electrons. The energy absorption coefficients were determined by the methods described by Cunningham and Johns.^3-4

5. APPLICATION OF THE DATA

Partial interaction coefficients and absorption coefficients are useful in any radiation transport or other radiation analysis application.

6. SOURCE AND SCOPE OF DATA

The data from the Ontario Cancer Institute are given for 94 elements and 25 composite materials covering the energy range 1 keV to 100 MeV. The reactions considered are coherent and incoherent scattering, photoelectric absorption, and pair production.

7. DISCUSSION OF THE DATA RETRIEVAL PROGRAMS

The Fortran 77 data retrieval programs are designed for use on minicomputers. The main data file, containing tables for all materials, is converted to a direct access file by the RANDOM program. The retrieval program, READX, is used to locate the data for selected materials and output the data to a sequential file.

8. DATA FORMAT AND COMPUTER

ASCII data files are on 4 360 K ds/dd diskettes or on magnetic tape (1 data file); IBM PC; Data General MV/family (retrieval program).

9. TYPICAL RUNNING TIME

READX runs interactively.

10. REFERENCES

a. Included in the documentation:

D. K. Trubey, Informal notes, ORNL (August 1988).

J. R. Cunningham and H. E. Johns, "Calculations of the Average Energy Absorbed in Photon Interactions," Med. Phys. 7(1), 51-54 (February 1980).

b. Background information:

E. F. Plechaty, D. E. Cullen, and R. J. Howerton, UCRL-50400, Vol. 6, Rev. 1 (National Technical Information Service, Springfield, VA, 1975).

H. E. Johns and J. R. Cunningham, The Physics of Radiology, Fourth Edition, Charles C. Thomas, Springfield, Ill. (1983).

11. CONTENTS OF LIBRARY

Included are the references in (10.a) data files, program files, and documentation files on one (1.2MB) DOS diskette. The program files are omitted from the PC version, which requires 4 DS/DD 360 K diskettes for the data and documentation files.

12. DATE OF ABSTRACT

July 1988.