1. NAME AND TITLE

INFLTB: Gamma-Ray Absorption Coefficient Calculation.

2. CONTRIBUTORS

Cleveland Clinic Foundation, Cleveland, OH; National Institute of Standards and Technology, Gaithersburg, MD; Oak Ridge National Laboratory, Oak Ridge, TN.

3. CODING LANGUAGE AND COMPUTER

Fortran 77; 386 PC; VAX family

4. NATURE OF PROBLEM SOLVED

INFLTB calculates mass energy transfer and mass energy absorption coefficients between 1 keV and 100 MeV for 29 elements and 14 mixtures and compounds of general dosimetric interest.

5. METHOD OF SOLUTION

The mass energy transfer coefficient is calculated from the sum of the interaction cross sections (atomic photo effect, Compton scattering, and pair plus triplet production) multiplied by their respective average fractions of energy transferred to electrons and positrons. The mass energy absorption coefficient is the product of the mass energy transfer coefficient and 1 - G, where G is the average fraction of the secondary electron (or positron) kinetic energy that is spent in bremmstrahlung production and in-flight positron annhilation.

6. RESTRICTIONS OR LIMITATIONS

Photon source energies are limited to values between 1 keV and 100 MeV. Radiation yield files are available only for 29 element and 14 compounds and mixtures.

7. TYPICAL RUNNING TIME

The running time depends on whether all energies are calculated or only the absorption edges. If only the edges are calculated, the calculation takes only a few seconds. The sample problem for lead (all energies) required about 10 hours on a 25 MHz PC 386.

8. COMPUTER HARDWARE REQUIREMENTS

The code was tested on a PC 386, but should run on all IBM PC compatible computers having a math coprocessor. A VAX version is also available.

9. COMPUTER SOFTWARE REQUIREMENTS

The code was written in Fortran 77 and was tested using the Microsoft Version 5.0 compiler. For implementation on other systems, the OPEN statements are placed in one subroutine (SETIO). The VAX version was tested using the VMS Fortran compiler.

10. REFERENCES

a. included in the documentation:

D. K. Trubey, informal notes (July 1992).

P. D. Higgins, F. H. Attix, J. H. Hubbell, S. M. Seltzer, M. J. Berger, and C. H. Sibata, "Mass Energy-Transfer and Absorption Coefficients, Including In-Flight Possitron Annihilation for Photon Energies 1 keV to 100 MeV," NISTIR 4812, U.S. Dept. of Commerce, National Institute of Standards and Technology (March 1992).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and a 5.25-in. DS/HD (1.2 MB) diskette.

12. DATE OF ABSTRACT

July 1992

KEYWORDS: GAMMA-RAY CROSS SECTION PROCESSING; KERMA; MICROCOMPUTER