RSIC COMPUTER CODE PSR-084

1. NAME AND TITLE

BOB-7 SERIES: Theory and Use of Gamma-Ray Spectrum Analysis Codes for Ge(Li) Detectors.

2. CONTRIBUTOR

Japan Atomic Energy Research Institute, Tokai Research Establishment, Ibaraki-ken, Japan.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; FACOM 230-60.

4. NATURE OF PROBLEM SOLVED

BOB-7 SERIES analyzes the Ge(Li) gamma-ray spectrum and other types of spectra to determine the energies and intensities of the peaks detected. The spectrum is plotted in option.

5. METHOD OF SOLUTION

The analysis is carried out by the photopeak method. The peak search is based on the first derivative method associated with various peak shape tests. The usual least squares method is adopted for resolving the complex of peaks. The line shape function as the basis of the fit is an asymmetric Gaussian with a tail; the asymmetry is realized with two half-Gaussian of different widths combined at the top. The shape of the base line under the peak can be selected out of the linear, exponential, and various stepwise functions.

6. RESTRICTIONS OR LIMITATIONS

BOB-7 SERIES accepts a spectrum containing up to 200 peaks. The preferable spectrum size is 4100 or less, though larger data sizes are acceptable. The multiplicity of the complex of peaks should not exceed 18 in the case of "with tail" or 19 in the case of "without tail," and the fitting range must be less than 200 channels.

The pile-up effect appearing in the measurement at a high counting rate causes attenuation of the peak area. Correction for the effect is not considered in BOB-7 SERIES. The channel shift during the measurement is not corrected, either. BOB-7 SERIES does not require the accurate FWHM value as an input datum; a rough measure of the peak width is, however, still necessary.

7. TYPICAL RUNNING TIME

The running time for BOB-7 SERIES depends upon the complexity of the spectrum rather than on the spectrum size. The analysis of a spectrum containing about 50 peaks with medium complexity (the maximum multiplicity among the complexes is about 5) requires approximately 10 seconds.

8. COMPUTER HARDWARE REQUIREMENTS

BOB-7 SERIES is operable on the FACOM 230-60 computer. A 103 K word memory is required. A CALCOMP plotter, one or two magnetic tape units or a card puncher are optional.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCES

H. Baba, "Usage of the BOB7-Series Programs for the Analysis of Ge(Li) Gamma-Ray Spectra," JAERI-M 7017 (March 1977).

H. Baba, T. Sekine, S. Baba, and H. Okashita, "A Method of the Gamma-Ray Spectrum Analysis: Fortran IV Programs 'BOB 73' for Ge(Li) Detectors and 'NAISAP' for NaI(Tl) Detectors," JAERI 1227 (June 1973).

H. Baba, H. Okashita, S. Baba, T. Suzuki, H. Umezawa, and H. Natsume, "Fast Computer Analysis of the Gamma Spectrum from Ge(Li) Detectors," J. Nucl. Sci. Technol., Vol. 8, No. 12 (December 1971) 41-50.

S. Baba, H. Baba, and H. Okashita, "BOB70: Program Code for the Analysis of Gamma Ray Spectra from a Ge(Li) Detector," ORNL-tr-2939/JAERI 1216 (April 1971).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source code and sample problem input and output,

12. DATE OF ABSTRACT

March 1984.