PSR-0542 MGA8.

1. NAME OR DESIGNATION OF PROGRAM:  MGA8

3. DESCRIPTION OF PROGRAM OR FUNCTION

The MGA (Multiple Group Analysis) program determines the relative abundances of plutonium and other actinide isotopes in different materials. The program analyzes spectra taken of such samples using a 4096-channel germanium (Ge) gamma-ray spectrometer. The code can be run in a one or two detector mode. The first spectrum, which is required and must be taken at a gain of 0.075 Kev/channel with a high resolution planar detector, contains the 0-300Kev energy region. The second spectrum, which is optional, must be taken at a gain of 0.25 Kev/channel; it becomes important when analyzing high burnup samples (concentration of Pu241 greater than one percent). Isotopic analysis precisions of one percent or better can be obtained, and no calibrations are required. The system also measures the abundances of U235, U238, Np237, and Am241. A special calibration option is available to perform a one-time peak-shape characterization when first using a new detector system.

4. METHODS

The basic method for determining the relative abundance of the isotopes of plutonium is to measure the intensity of two or more peaks from gamma rays of similar energy, but arising from different isotopes. Since the gamma-ray emission probabilities and half-lives are known, the atom ratios can be calculated provided relative detection efficiencies for the peaks can be estimated.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM:  None noted.

6. TYPICAL RUNNING TIME:  Analysis time is typically less than one minute.

10. REFERENCES

Background references:
- R. Gunnink, MGA2 - A One-Detector Code for Rapid High-Precision Plutonium Measurements UCRL-96016 Rev. 1, Preprint (July 1987).
- R. Gunnink, A New One-Detector Analysis Method for Rapid High-Precision Plutonium Isotopic Measurements, Reprinted from the Proceedings of the 9th ESARDA Symposium on Safeguards and Nuclear Material Management, London, UK., pp. 167-171 (May 12-14, 1987).

- R. Gunnink:
"MGA - A Gamma-Ray Spectrum Analysis Code for Determining Plutonium Isotopic
Abundances, Volume 1, Methods and Algorithms," UCRL-LR-103220, Vol.1 (April 3,
1990).
- R. Gunnink:
"MGA - A Gamma-Ray Spectrum Analysis Code for Determining Plutonium Isotopic
Abundances, Volume 2, A Guide to Using MGA," UCRL-LR-103220, Vol.2 (Sept. 1,
1990).

11. HARDWARE REQUIREMENTS

MGA runs on personal computers and on DEC VAX series under VMS.

13. SOFTWARE REQUIREMENTS

The package contains the Fortran-77 source code and executables for Windows and VAX VMS. The included PC executable was compiled with Microsoft Fortran 77. The Windows release was tested by RSICC on Pentium PC's running the Microsoft Windows XP and Vista operating systems with MS FORTRAN 5.1.

15. NAME AND ESTABLISHMENT OF AUTHORS

Contributed by:
                Radiation Safety Information Computational Center
                Oak Ridge National Laboratory
                Oak Ridge, Tennessee, U.S.A.
Developed by:   Lawrence Livermore National Laboratory, Livermore, California,
                through the Energy Science and Technology Software Center,
                Oak Ridge, Tennessee, U.S.A.

Fortran-77 source code
Executables for Windows and VAX VMS
Electronic documentation