1. NAME AND TITLE
CERPI-CEREL: Code Systems for Automatic Analysis of Gamma-Ray Spectra Obtained
with Ge(Li) Detectors.
Institute of Physics, University of Rome, Rome, Italy.
Comitato Nazionale per l'Energia Nucleare, Centro di Studi Nucleari della Casaccia, Roma, Italia.
3. CODING LANGUAGE AND COMPUTER
Fortran IV; IBM 360/370.
4. NATURE OF PROBLEM SOLVED
CERPI and CEREL are automatic analyzers of gamma-ray spectra obtained with Ge(Li) detectors. CERPI analyzes experimental gamma-ray spectra in order to find the photopeak positions and areas. CEREL looks for those elements or nuclides which are potential emitters of the gamma-lines. It is possible to search by elements or nuclides, depending on the input parameter.
CERPI-CEREL contains features such as determination of peak energies and intensities, nuclide
identification, and mass computation.
5. METHOD OF SOLUTION
CERPI detects the significant peaks in the spectrum by observing the behavior of the second derivative function after random variations in counts per channel have been minimized by the application of a smoothing filter function. Once the peaks have been identified, CERPI determines their mass centers, areas and corresponding errors with a least-squares fit. Each significant peak is fitted with a Gaussian function superimposed on a linear or quadratic background. The determination of the minimum of the X2 function is accomplished by a variant of the gradient method.
CEREL does automatic isotope identification on the basis of gamma-ray energy comparison. It
contains features such as determination of peak energies and intensities, nuclide identification, and
mass computation. The energy calibration curve is determined starting from some known energy lines
and by means of a fitting procedure with orthogonal polynomials using the F test for the automatic
determination of the polynomial order. The single and double escape peaks are used for a more
careful determination of the photopeak intensities and then removed from the observed spectrum.
Pagden's isotope catalog is used for both nuclide identification and mass calculation.
6. RESTRICTIONS OR LIMITATIONS
The high precision and sensitivity of CERPI-CEREL make it very suitable to very complex spectrum analyses where many peaks overlap each other. This high sensitivity may imply the introduction of some spurious peaks. The higher the number of peaks identified, especially the number of spurious ones, the higher is the probability of introducing fictitious elements and the more complicated is the resolution of the mass matrix.
Particular care must also be taken in the choice of the input parameters because the fitting
procedure is affected by this choice.
7. TYPICAL RUNNING TIME
The running times of CERPI-CEREL depend strongly on the complexity of the spectrum and the
number of channels in a typical peak. On an IBM 360/75 system, the analysis of a 4096-channel
spectrum requires approximately 4 min of CPU processor time if about 250 peaks are printed on the
8. COMPUTER HARDWARE REQUIREMENTS
CERPI-CEREL is operable on the IBM 360/370 computers.
9. COMPUTER SOFTWARE REQUIREMENTS
A Fortran IV compiler is required.
M. Giannini, P. R. Oliva, and C. Ramorino, "CERPI and CEREL, Two Computer Codes for the Automatic Identification and Determination of Gamma Emitters in Thermal Neutron Activated Samples," RT/FI(78)5 (May 1978).
M. Giannini, P. R. Oliva, and M. C. Ramorino, "Automatic Element Analysis in Thermal Neutron Activated Samples," RT/FI(78)15 (October 1978).
M. Giannini, P. R. Oliva, and M. C. Ramorino, "Automatic Peak Identification in the Analysis
of Gamma-Ray Spectra Obtained with Ge(Li) Detectors," RT/FI(72)14 (April 1972).
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, the isotope catalogue and the array listings.
12. DATE OF ABSTRACT
KEYWORDS: ACTIVATION SPECTRA ANALYSIS; DATA PROCESSING, SPECTRA; GAMMA-RAY SPECTRUM ANALYSIS; GERMANIUM (Ge(Li)) DETECTOR; UNFOLDING