Click
on the picture for a larger versionThe FitzPeaks Gamma Analysis Software is a combined research and general purpose gamma spectroscopy analysis and calibration program capable of operating on spectral data from a variety of different manufacturer's systems. It is designed to run under all 32 bit versions of Microsoft® Windows™
Click
on the picture for a larger version
The main algorithms used for finding and fitting peaks, and performing the quantitative analysis are based on methods presented in a paper describing the program SAMPO80 produced by M.J. Koskelo, P.A. Aarnio and J.T. Routti of the Helsinki University of Technology, Finland.
The peak search algorithm is based on finding minima in the smoothed second difference of the spectral data. The peak fitting is performed using a linear least squares routine, fitting the data to a Gaussian function with an exponential tail on either the low energy, or both sides of a peak. There is an optional iterative fitting for peak position, width, and low energy tailing.
The program is capable of operating in a range of modes, from a fully automated analysis through to a completely interactive mode. In the interactive modes comprehensive displays are presented, allowing the user to insert new peaks into the spectrum, change the widths of fitting regions, change the type of background continuum used, etc.
The following animated example shows the interactive display that can be obtained when peak fitting is being performed. Possible nuclides with the library energies and gamma emission probabilities can be listed for the current cursor position. The program has the facility of automatically searching the residual data for possible new peaks, and then inserting the new peak:-
The nuclide identification and activity calculation is done by forming an interference matrix and solving interfering sets using a weighted least squares method. These algorithms have been enhanced and refined taking advantage of the capabilities of a modern day personal computer. Some of the enhancements, which are selectable as options are as follows-
There are report files produced from each stage of the analysis, including a full and a brief activity report. The brief activity report contains the parameters stored in the spectral data file, the nuclides found and their activities, optional nuclide descriptions, and limit of detection values if required. This report is produced using a template text file which can be easily modified by the user. This enables the user to select which parameters are listed, the format of the activity values, as well as inserting any amount of additional text to be included in the report.
The program has the facility of automatically appending the results of each analysis performed to a database or spreadsheet file which is compatible with most commercially available programs.
The calibration section of the program provides the facility to calibrate for energy, peak shape and efficiency. This enables the full quantitative analysis of spectral data files that consist of only raw channel data to be performed by the software.
There is also a version of the software available that is optimised for low resolution detectors such as Sodium Iodide. An evaluation copy of FitzPeaks NaI can be downloaded by clicking here
Jim Fitzgerald, JF Computing Services, 17 Chapel Road,
STANFORD IN THE VALE, Oxfordshire, SN7 8LE
Tel: +44 (0)1367
710543 E-mail:
jim@jimfitz.co.uk
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Copyright © Jim
Fitzgerald 1991-2016
Last updated 8th October 2016