1. NAME AND TITLE

SAMPO80: Gamma-Ray Spectrum Analysis Method for Minicomputers.

AUXILIARY ROUTINES

SAMPOSHAPE: Performs peak shape calibration.

SAMPOFIT: Performs peak search and fitting.

SAMPOID: Performs nuclide identification.

SAMPO, originally called Sisyphus, was developed on the CDC 6600 computer at the Lawrence Berkeley Laboratory of the University of California in 1969 in support of the author's doctoral dissertation. The analysis methods employed in this minicomputer version are simplified from those in the original code. Another version of this code, PSR-186/SAMPO-LRC, was modified at the London Reactor Centre and runs on the CDC 6600 computer.

2. CONTRIBUTORS

Helsinki University of Technology, Nuclear Engineering Laboratory, Espoo, Finland.

OECD Nuclear Energy Agency Data Bank, Gif-sur-Yvette, France.

3. CODING LANGUAGE AND COMPUTER

Fortran 5; Data General Nova 2.

4. NATURE OF PROBLEM SOLVED

SAMPO80 is a rapid and accurate analysis program for gamma-ray spectra measured with Ge(Li) or HPGe detectors. SAMPO80 consists of three separate parts, the shape calibration part SAMPOSHAPE, the peak search and fitting part SAMPOFIT, and the nuclide identification part SAMPOID.

5. METHOD OF SOLUTION

The shape calibration procedure uses a non-linear least squares algorithm with a variable metric method. Some other features include: peak location with a smoothed second difference method, peak area calculation with a linear least squares fit to predefined peak shapes, and nuclide identification with a linear least squares fit based on associated lines.

6. RESTRICTIONS OR LIMITATIONS

Number of shape calibration points allowed: 20

Number of energy calibration points allowed: 20

Number of efficiency calibration points allowed: 20

Maximum number of found peaks: 100

Maximum number of fitted peaks: 100

Maximum number of peaks in a multiplet: 5

Maximum number of channels in a fitting interval: 50

Maximum number of peaks for nuclide identification: 80

Maximum number of identified nuclides: 30

Maximum number of lines per nuclide: 30

7. TYPICAL RUNNING TIME

On a Data General Eclipse S/140 with microcoded floating point instruction set, 25 seconds are required per shape calibration of one peak, 2 seconds per peak for peak search and fitting, and 3 seconds per identified nuclide for identification.

8. COMPUTER HARDWARE REQUIREMENTS

SAMPO80 is operable on the Data General Nova 2 minicomputer with a 32 kiloword central memory and a supporting disk unit.

9. COMPUTER SOFTWARE REQUIREMENTS

This version of SAMPO80 is run under the Data General Real Time Disk Operating System (RDOS) and requires a Fortran 5 compiler.

10. REFERENCES

P. A. Aarnio, J. T. Routti, J. V. Sandberg and M. J. Winberg, "Adapting Gamma-Spectrum Analysis Program SAMPO for Microcomputers," Nucl. Instrum. Methods 219, 173-175 (May 1983).

J. T. Routti, "SAMPO, a Fortran IV Program for Computer Analysis of Gamma Spectra from Ge(Li) Detectors, and for Other Spectra with Peaks," UCRL-19452 (October 1969).

P. A. Aarnio, M. J. Koskelo, "Computerized Gamma Spectrometry at the Helsinki University of Technology," Nucl. Instrum. Meth. 193 (1982) 129-134.

M. Koskelo, P. Aarnio, and J. Routti, "SAMPO80: An Accurate Gamma Spectrum Analysis Method for Minicomputers," Nucl. Instrum. Meth. 190 (1981) 89-99.

M. J. Koskelo, P. A. Aarnio, and J. T. Routti, "SAMPO80: Minicomputer Program for Gamma Spectrum Analysis with nuclide Identification," Comput. Phys. Comm. 24 (1981) 11-35.

J. T. Routti and S. G. Prussin, "Photopeak Method for the Analysis of Gamma-Ray Spectra from Semiconductor Detectors," Nucl. Instrum. Meth. 72 (1969) 125-142.

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.44MB) DOS diskette which contains the source codes, sample problem input and output, and console dialogue.

12. DATE OF ABSTRACT

January 1984; revised April 1984, October 1991.