**1. NAME AND TITLE**

TMMS: Gamma-Ray Penetration Shielding Code System, Transmission Matrix Method.

**2. CONTRIBUTOR**

Engineering Research Institute, Iowa State University, Ames, Iowa.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN IV; IBM 360/370.

**4. NATURE OF PROBLEM SOLVED**

Investigations have been made into applications of the transmission matrix method for radiation shielding. The purpose of the analysis was to investigate the possibilities of developing a point kernel from the transmission matrix method as it was developed for plane geometry. Investigations were made into transmission of gamma radiation through plane multilayered geometry for point isotropic sources. Investigations also were made into applications of the point kernel for certain standard geometry sources in a homogeneous medium. These applications included integrating the point kernel over these sources.

As a result of these investigations, the TMMS code was developed which can perform the
necessary operations in the transmission matrix method effectively and efficiently. The code
operates in a series of four steps, the first three being used only once for a particular material with
a fixed energy group structure and angular expansion. The fourth step is the shielding step where
the shielding design calculations are performed.

**5. METHOD OF SOLUTION**

TMMS is a transmission matrix method shielding code for gamma-ray shielding for plane and
point geometry in finite and infinite media for one-, two-, and three-layered slabs. In the shielding
calculations, the source is specified both in energy and angle, and the code calculates energy flux
density transmitted and reflected. Also calculated are various appropriate buildup factor data for
the media.

**6. RESTRICTIONS OR LIMITATIONS**

None noted.

**7. TYPICAL RUNNING TIME**

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

**8. COMPUTER HARDWARE REQUIREMENTS**

TMMS is operable on the IBM 360/370 computers.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A FORTRAN IV compiler is required.

**10. REFERENCE**

A. F. Rohach, "Final Report, Applications of the Transmission Matrix to Radiation Shielding,"
Project 810-S, ISU-ERI-AMES-72014 (February 1972).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and one (1.2MB) DOS diskette which contains the source
codes, DD card images, and sample problem input and output.

**12. DATE OF ABSTRACT**

October 1975.

**KEYWORDS: ** TRANSMISSION MATRIX; ONE-DIMENSION; GAMMA-RAY; SLAB