**RSIC COMPUTER CODE PSR-074**

**1. NAME AND TITLE**

TECALC: Interactive Calculation of Compton Coherent and Photoelectric Mass Attenuation
Coefficients for Photons (E<1 MeV), and the Mass Absorption Coefficient for Known
Materials.

**2. CONTRIBUTOR**

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

**3. CODING LANGUAGE AND COMPUTER**

BASIC, ASCII; PDP-10.

**4. NATURE OF PROBLEM SOLVED**

TECALC is a BASIC program, written for the PDP-10, which can be used (1) to calculate the Compton, coherent, and photoelectric partial mass attenuation coefficients, the total mass attenuation coefficient, and the mass absorption coefficient for known materials and (2) in an interactive, iterative mode to assist the user in formulating mixtures of materials which have partial mass attenuation coefficients similar to a given material of interest.

TECALC is capable of handling complex mixtures or solutions of compounds in a manner which simplifies input. It can be used to calculate coefficients for mixtures or solutions of compounds of 19 of the most common elements in biological or biological-equivalent materials. Coefficients are calculated at 17 logarithmically spaced intervals from 10 keV to 1 MeV.

TECALC is designed to be used in the timesharing mode and can be run by a user who has only
a rudimentary knowledge of BASIC programming.

**5. METHOD OF SOLUTION**

TECALC calculates attenuation and absorption coefficients for materials and compares these
coefficients to those of a previously designated reference material at the user's option. To facilitate
the formulation of equivalent materials, TECALC allows the user to iteratively adjust the proportions
of the components of a trial material.

**6. RESTRICTIONS OR LIMITATIONS**

None noted.

**7. TYPICAL RUNNING TIME**

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

**8. COMPUTER HARDWARE REQUIREMENTS**

TECALC is operable on the PDP-10 computer.

**9. COMPUTER SOFTWARE REQUIREMENTS**

BASIC and ASCII compilers are required.

**10. REFERENCE**

P. S. Stansbury, "TECALC--A Program to Calculate Compton, Coherent, and Photoelectric Mass
Attenuation Coefficients for Photons with Energies Less Than 1 MeV and to Assist in the Evaluation
and Formulation of Photon-Equivalent Materials," ORNL-TM-4451 (January 1974).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and one (1.2MB) DOS diskette which contains the source
code input.

**12. DATE OF ABSTRACT**

February 1984.

**KEYWORDS:** GAMMA-RAY CROSS SECTION PROCESSING; INTERACTIVE, ON-LINE