1. NAME AND TITLE

GRETEL: Analyzer and Processor of Ge(Li) Gamma-Ray Spectrometric Data.

2. CONTRIBUTOR

Joint Nuclear Research Centre, Ispra Establishment (EURATOM), Ispra, Italy.

OECD Nuclear Energy Agency Computer Program Library, Ispra, Italy.

3. CODING LANGUAGE AND COMPUTER

Fortran IV and Assembler language; IBM 370.

4. NATURE OF PROBLEM SOLVED

GRETEL performs the quantitative analysis of gamma-ray spectra obtained by Ge(Li) detectors using special "oriented libraries" which are prepared for each particular problem.

5. METHOD OF SOLUTION

The computer routines which detect and evaluate peak areas perform the following operations: 1) local smoothing of the spectrum, 2) first derivative of the smoothed spectrum, 3) peak location according to the change of sign of the first derivative, 4) computation of the net area of each peak found. GRETEL can also detect and compute double peaks from a study of the behavior of the first derivative.

An energy calibration source is counted by GRETEL as the first spectrum of the series; then the unknown neutron activated samples are successively counted. The analysis is carried out by the single @comparator method. Irradiation and decay times, weight of samples and neutron flux are manually assigned by the operator. Peaks in the gamma spectrum are searched, identified and measured by following the instructions of special "oriented libraries" which are prepared for each particular problem.

6. RESTRICTIONS OR LIMITATIONS

The maximum number of calibration peaks is 10. The maximum number of elements of the "oriented library" is 50. The maximum number of channels of the spectrometer which can be used is 4096. No limitation exists on the number of spectra to be treated. It is imperative that the calibration spectrum is always the first of the set.

CALCOMP plotting must be requested separately after the complete running of the program.

7. TYPICAL RUNNING TIME

For a typical analysis of 30 spectra of 2048 channels (calibration spectrum plus 29 unknown), with an "oriented library" of 30 elements, the running time is about 30 seconds (object program).

8. COMPUTER HARDWARE REQUIREMENTS

GRETEL is operable on the IBM 370 computers. The plotting routines are for a CALCOMP 900 off-line plotter.

9. COMPUTER SOFTWARE REQUIREMENTS

Fortran IV-G and Assembler language compilers are required.

10. REFERENCE

G. Guzzi and J. Cuypers, "GRETEL, A Computer Program for Gamma Ray Spectrometry with Ge(Li) Detectors," EUR 5117 e (1974).

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, plus the plotting subroutines.

12. DATE OF ABSTRACT

March 1984.