1. NAME AND TITLE

STREAM: A Three-Dimensional Cylindrical-Geometry Monte Carlo Ray Tracing Code for Computing Light Transmission.

2. CONTRIBUTOR

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

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; CDC 7600.

4. NATURE OF PROBLEM SOLVED

STREAM theoretically tests light transmission through complex cylindrically symmetric SHIVA chamber geometries. (SHIVA is a Z-pinch device used to produce hot dense radiating plasmas by the ionization and J and B implosion of a short cylindrical foil.) If sufficient UV light is transmitted from the ionized foil to the chamber insulator, the resulting ionization of the insulator may cause the chamber to break down electrically.

5. METHOD OF SOLUTION

Three-dimensional cylindrical geometry with theta symmetry is used. Specular or diffuse reflections or any combination of the two phenomena may be specified. Diffuse reflections can be treated in several ways, for example, any distribution (isotropic or cosine distributions are standard) is allowed, and it can be oriented around the surface normal or along the specular reflection angle. Adsorption is calculated for each reflection, and it is a function of the angle of incidence, index of refraction, and extinction coefficient. The output includes relative intensity crossing designated surfaces in the geometry. The input intensity is unity. An optional output file is available for 2-D microfiche plotting of successful (hits on the insulator) photon paths.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

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

8. COMPUTER HARDWARE REQUIREMENTS

STREAM is operable on the CDC 7600 computer.

9. COMPUTER SOFTWARE REQUIREMENTS

A FORTRAN IV compiler is required.

10. REFERENCE

J. A. Justice, "STREAM: A Three-Dimensional Monte Carlo Ray Tracing Code in Cylindrical Geometry," AFWL-TR-76-206 (February 1977).

11. CONTENTS OF CODE PACKAGE

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

12. DATE OF ABSTRACT

August 1979; reviewed March 1982.