RSICC CODE PACKAGE PSR-506
1. NAME AND TITLE
GAMANAL: Code System for Computerized Quantitative Analysis by Gamma-Ray Spectrometry.
Lawrence Livermore National Laboratory Livermore, California, through the OECD NEA Data Bank, Issy-les-Moulineaux, France.
3. CODING LANGUAGE AND COMPUTER
Fortran-77; DEC VAX11/750 and DEC VAX11/780 (P00506D0VAX00).
4. NATURE OF THE PROBLEM SOLVED
GAMANAL provides a complete qualitative and quantitative analysis of mixtures of radioactive species such as fission products by computer interpretation of high-resolution gamma-ray spectra. The program first determines and removes the background or Compton continuum under the peaks in a spectrum to locate the peak regions. This is done by examining the pulse-height spectrum data for background and peak regions and then fitting these data with the proper shape functions. When determining the photon emission rate, corrections are made for the effects of geometry, attenuation, and detector efficiency. Nonlinearities in the equipment are taken into account in setting up the energy scale. The total intensities and gamma-ray energies are listed and plotted and,if no further reduction of the spectral data is requested, the program repeats this process with the next spectrum. Otherwise, a library of decay scheme information is searched to make a tentative identification of each of the peaks. These proposed nuclides are examined for interferences between their photopeaks to determine which isotope is responsible for the peak in question. A matrix of the probable nuclides and the identified peaks is constructed and is then divided into sets of nuclides which interfere with each other. These independent sets are combined to form a working matrix. A least-squares solution of the corresponding set of simultaneous equations is made to determine the amounts of the various component nuclides present and their estimated errors.
5. METHOD OF SOLUTION
Peaks are located by a point-by-point examination of the first and second derivatives within the bounds of identified peak regions using statistically-weighted tests. Peak shapes are characterized by a shape analysis functions, which is the sum of a Gaussian and a tailing term. The data points in an overlapping peak multiplet are considered to be linear combinations of the contributions from each peak. A detailed analysis of each peak region is done by keeping some shape parameters fixed and obtaining the best least-squares value for all free parameters using the Newton-Raphson (Gauss) iterative technique. A Taylor expansion about trial values is used to linearize the equations. A matrix of linear equations that describe the spectral intensities is formed to correct for unresolved peak interferences. A Gaussian function is used to determine how well the component nuclide's gamma-ray energy agrees with the energy of the peak in question.
6. RESTRICTIONS OR LIMITATIONS
7. TYPICAL RUNNING TIME
On a VAX-11/780 computer :
Compile : Library program 16.3 sec
GAMANAL 271.4 sec
DIGRAPH routines 53.5 sec
DIGLIB routines 315 sec
Run : 71 sec for test case with VERSAPLOT o/p
8. COMPUTER HARDWARE REQUIREMENTS
GAMANAL was tested on a VAX-11/780 at the NEA Data Bank in 1988 and was not tested when it was contributed to RSICC in February 2001. The source files in this package will require modifications to run on other computers.
9. COMPUTER SOFTWARE REQUIREMENTS
The codes were developed under VMS V4.4 and require a VAX Fortran 77 compiler. LIBETP, an auxiliary program which is used to generate a GAMANAL decay-scheme library, is included. Graphic output is provided by DIGLIB and DIGRAPH, which are included. DIGLIB is a collection of Fortran-callable subroutines for two-dimensional plots. DIGRAPH acts as a shell for the GKS graphics routines.
a: included in document:
R. Gunnink, J. B. Niday, "Computerized Quantitative Analysis by Gamma-Ray Spectrometry, Vol I. Description of the GAMANAL Program," UCRL-51061, Vol. I (March 1972).
R. Gunnink, J. B. Niday, "Computerized Quantitative Analysis by Gamma-Ray Spectrometry, Vol III. A User's Guide to GAMANAL," UCRL-51061, Vol. III (July 1971).
R. Gunnink, J. B. Niday, "Computerized Quantitative Analysis by Gamma-Ray Spectrometry, Vol IV. Auxiliary Program for GAMANAL," UCRL-51061, Vol. IV (June 1972).
b: background information:
R. Gunnink, J. B. Niday, "Computerized Quantitative Analysis by Gamma-Ray Spectrometry, Vol II. Source Listing of the GAMANAL Program," UCRL-51061, Vol. II (1971).
R. Gunnink, W. D. Ruhter, and J. B. Niday, "GRPANL: A Suite of Computer Programs for Analyzing Complex Ge and Alpha-Particle Detector Spectra, Volume 1," UCRL-53861, Vol. 1 (May 1988). Available from RSICC as PSR-321.
11. CONTENTS OF CODE PACKAGE
Included are the referenced documents in (10.a) and a self-extracting compressed file on a DS/HD diskette, which contains the Fortran source and sample problem. After file decompression, there are 230 files that are about 1.79 MB.
12. DATE OF ABSTRACT
KEYWORDS: GAMMA-RAY SPECTRUM ANALYSIS; UNFOLDING; GERMANIUM (GE(LI)) DETECTOR