1. NAME AND TITLE

SKYSHINE-III: Calculation of the Effects of Structure Design on Neutron, Primary Gamma-Ray and Secondary Gamma-Ray Dose Rates in Air.

SKYIII-PC: PC version of SKYSHINE-III

2. CONTRIBUTOR

SKYSHINE III: Radiation Research Associates, Fort Worth, Texas.

SKYIII-PC: J. K. Warkentin, Fort Worth, Texas.

3. CODING LANGUAGE AND COMPUTER

SKYSHINE-III: FORTRAN 77; VAX (C00289/DOVAX/00).

SKYIII-PC: FORTRAN 77; IBM PC Compatible with coprocessor (C00289/IBMPC/01).

4. NATURE OF PROBLEM SOLVED

SKYSHINE was designed to aid in the evaluation of the effects of structure geometry on the gamma-ray dose rate at given detector positions outside of a building housing N16 gamma-ray sources. The program considers a rectangular structure enclosed by four walls and a roof. Each of the walls and the roof of the building may be subdivided into up to nine different areas, representing different materials or different thicknesses of the same material for those positions of the wall or roof. Basic sets of iron and concrete slab transmission and reflection data for 6.2 MeV gamma rays are part of the SKYSHINE block data. These data, as well as parametric air transport data for line-beam sources at a number of energies between 0.6 MeV and 6.2 MeV and ranges to 3750 ft, are used to estimate the various components of the gamma-ray dose rate at positions outside of the building. The gamma-ray source is assumed to be a 6.2-MeV point-isotropic source.

SKYSHINE-III provides an increase in versatility over the original SKYSHINE code in that it addresses both neutron and gamma-ray point sources. In addition, the emitted radiation may be characterized by an energy emission spectrum defined by the user. A new SKYSHINE data base is also included.

SKYIII-PC is a PC version of SKYSHINE-III. Only minor modifications were made in converting for PC use. The June 1997 replacement of the PC version corrects the previously existing index problem leading to erroneous results for the "wall-scattered/air-scattered" contribution if a roof is modeled. Associated with these changes is the precaution that the detector height should always be lower than the base of the roof. Erroneous results for the roof portion of the "wall-scattered/air- attenuated" contribution will occur if a roof is modeled and the detector is not below the roof plane.

5. METHOD OF SOLUTION

The Monte Carlo method is used in SKYSHINE-III to integrate the emitted radiation over the solid angles subtended by each wall, the floor, and the roof of the structure. The Monte Carlo method is also used in integrating the products of the shield, transmitted and reflected energy, and angle distributions times the air-scattered dose rates over exit energies and angles. The PC version, SKYIII-PC, has been modified to employ the MIRAN random number generator.

6. RESTRICTIONS OR LIMITATIONS

Restrictions and limitations are discussed in the document. These restrictions and limitations are also applicable to the PC Version, SKYIII-PC.

7. TYPICAL RUNNING TIME

The sample problem test case described in the SKYSHINE-III document required about 1 minute of wall clock time on the VAX 8600. Execution of SKYIII-PC for the 4 test cases required approximately 7 minutes on the Compaq Pentium 60.

8. COMPUTER HARDWARE REQUIREMENTS

SKYSHINE-III was developed on a small VAX and tested at RSICC on a VAX 8600. The SKYIII-PC runs on IBM compatible personal computers with a coprocessor.

9. COMPUTER SOFTWARE REQUIREMENTS

The VAX VMS FORTRAN 77 compiler, version 4.6, was used at RSICC. SKYIII-PC was compiled with the IBM FORTRAN/2 Compiler Version 4.00 and can be run in a DOS window of Windows95.

10. REFERENCES

SKYSHINE-III: C. M. Lampley, M. C. Andrews and M. B. Wells, "The SKYSHINE-III Procedure: Calculation of the Effects of Structure Design on Neutron, Primary Gamma-Ray and Secondary Gamma-Ray Dose Rates in Air," RRA-T8209A (June 1982, revised September 1988).

Loading instructions, Radiation Research Associates, Inc. (September 1988).

SKYIII-PC: J. K. Warkentin, "Transmittal Letter" (January 31, 1997).

J. K. Warkentin, "SKYIIIPC Notes," Informal Notes (January 1997).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one DS/HD 3.5-inch diskette (1.44 MB) in DOS format which contains the source code and sample problem input and output; total records 47,302 for the VAX version. SKYIII-PC is transmitted on 2 DS/HD 3.5" (1.44MB) diskettes in self-extracting compressed DOS files and includes executables.

12. DATE OF ABSTRACT

March 1982, revised December 1988, February 1991, February 1992, June 1997.