[en] High-resolution gamma spectroscopy with germanium detectors and related computer methods has been in the development process for some 30 yr. The emergence of personal computers (PCs) with remarkable computing power, large working and external memories, fast graphics, and standardized operating systems, allowing easy portability of programs, has made it possible to develop advanced and cost-effective PC-based analysis systems. Emphasis has been on the implementation of mature methods to user-friendly and robust codes. Research interest has turned to automated analysis, rigorous error analysis, and interpretation of results using expert systems and knowledge bases. The problem setting, state-of-the-art practices, and development trends of different phases of analysis are discussed in this paper. This is mostly based on experience with the PC-based MicroSAMPO code, which is a greatly extended derivative of the earlier mainframe SAMPO code

[en] Gamma spectrum analysis is currently a widely used tool in many fields. Correct quantitative identification of radionuclides in a sample is often vital when making decisions for further actions. This requires a substantial amount of expertise on the part of the laboratory personnel. Full identification of a complex spectrum takes many hours. Nuclide identification is an iterative process, where the analyst aims to find correct nuclides by decreasing the amount of possibilities by trial and error. Although the process of identification is quite complex, it can be formulated using 'rules of thumb' combined with exact mathematical analysis. Thus, an expert system can be built, where the knowledge of a human expert is converted to explicit rules. These rules can be processed using an inference engine, a specialized program for reasoning. The authors are currently developing an expert system that will carry out the quantitative nuclide identification with a minimum of user intervention. Reasoning process is performed by an inference engine written in C-language. The system uses a database containing over 2,000 radionuclides with about 48,000 gamma transitions. Spectra are provided in preprocessed format, where peak energies, intensities and backgrounds with corresponding error estimates have been calculated by analysis program MicroSAMPO

[en] Several expert system development tools are available for personal computers today. We have used one of the LISP-based high end tools for nearly two years in developing an expert system for identification of gamma sources. The system contains a radionuclide database of 2055 nuclides and 48000 gamma transitions with a knowledge base of about sixty rules. This application combines a LISP-based inference engine with database management and relatively heavy numerical calculations performed using C-language. The most important feature needed has been the possibility to use LISP and C together with the more advanced object oriented features of the development tool. Main difficulties have been long response times and the big amount (10-16 MB) of computer memory required

[en] SAMPO for Windows is a high performance gamma spectrum analysis program. All the measurement, analysis and NAA phases can be done either under full interactive use control or user defined tasks can be used for automated measurement and analysis sequences including control of MCAs and sample changers. High resolution gamma-ray spectroscopy together with the possibility to resolve complex multiplets with high accuracy makes SAMPO very suitable for INAA. On the other hand, the possibility to automate analysis sequences allows it use effectively also in all routine NAA measurements. NAA in SAMPO is accomplished using comparative methods. Spectra of standards, flux monitors, controls and actual samples are analyzed normally to obtain the peak areas which are optionally corrected for decay. In the comparison the flux monitor results are used to correct for variations in the effective neutron flux. An optional irradiation position correction can also be applied. The controls are used to alarm for possible deviations in the results. The sophisticated spectrum analysis methods used together with the comparative NAA and monitors give accurate results limited by the systematic effects only. The Windows environment provides ease of use and further processing power is available through the interface to expert system identification of nuclides. (author) 19 refs.; 1 tab

[en] In this paper we describe our approach to designing a system for rapid and accurate processing of gamma spectra. Our measurements are done in a separate measuring station which consists of conventional equipment centered around a multichannel analyzer. The measured spectra are then transferred to a Nova 2 minicomputer based analysis station via a 70 m long cable at a 9600 baud rate with a special control program. Analyses can be perfomed with our new SAMPO80 code on the Nova or the data can be further transferred into the computer network of the University with another control program. Various aspects of the system design and development are discussed. (orig.)

[en] A method for analyzing electron induced X-ray fluorescence spectra with a high degree of accuracy is presented. The method is based on fitting of complex multiplets using precalibrated peak shapes and on an accurate description of the global background function. Element identification and matrix correction procedures are included. Matrix correction is shown to be applicable for complex matrix effects. Further tests are needed to verify the results and the consistency of their error estimates under differing measurement and sample conditions. (orig.)

[en] SAMPO 90 is a high performance gamma spectrum analysis program for personal computers. It uses high resolution color graphics to display calibrations, spectra, fitting results as multiplet components, and analysis results. All the analysis phases can be done either under full interactive user control or by using macros for automated measurement and analysis sequences including the control of MCAs and sample changers. Semi-automated calibrations for peak shapes (Gaussian with exponential tails), detector efficiency, and energy are available with a possibility for user intervention through interactive graphics. Accurate peak area determination of even the most complex multiplets, of up to 32 components, is accomplished using linear, non-linear and mixed mode fitting, where the component energies and areas can be either frozen or allowed to float in arbitrary combinations. Nuclide identification is done using associated lines techniques which allow interference correction for fully overlapping peaks. Peaked Background Subtraction can be performed and Minimum Detectable Activities calculated. Attenuation corrections can be taken into account in detector efficiency calculation. The most common PC-based MCA spectrum formats (Canberra S100, Ortec ACE, Nucleus PCA, ND AccuSpec) are supported as well as ASCII spectrum files. A gamma-line library is included together with an editor for user configurable libraries. The analysis reports and program parameters are fully customizable. Function key macros can be used to automate the most common analysis procedures. Small batch type modules are additionally available for routine work. SAMPO 90 is a result of over twenty man years of programming and contains 25,000 lines of Fortran, 10,000 lines of C, and 12,000 lines of assembler

[en] The widely used SAMPO Ge(Li) and HPGe gamma spectrum analysis program was adapted to IBM PC in a thoroughly revised version MicroSAMPO. The program is intended for peak search, peak fitting, nuclide identification and activity calculations. The use of calibrated peak shape functions for peak area determination makes it possible to resolve complex multiplets with strongly overlapping peaks. Menu-driven user interface, colour graphics displays, semi-automatic calibrations and interactive options were designed to make the program more user-friendly. It is well suited for both spectroscopic research and routine analysis. (author) 3 refs.; 3 figs

[en] Radionuclide identification from a measured gamma-spectrum is an iterative process, where the analyst aims to find correct nuclides by increasing the amount of possibilities by trial and error. Although the process of identification is quite complex, it can be formulated using 'rules of thumb' combined with exact mathematical analysis. Thus, an expert system can be built, where the knowledge of a human expert is converted to explicit rules. In this paper expert system SHAMAN is presented, which carries out the qualitative nuclide identification and activity determination with minimum of user intervention. The reasoning process is performed by an inference engine written in C-language. The system uses a database containing over 2000 radionuclides with about 48000 gamma-transitions. Spectra are provided in preprocessed format, where peak energies, intensities and backgrounds with respective error estimates have been calculated by a separate analysis program. (author) 12 refs

[en] An expert system coupled with the gamma spectrum analysis system SAMPO has been developed for automating the qualitative identification of radionuclides as well as for determining the quantitative parameters of the spectrum components. The program is written in C-language and runs in various environments ranging from PCs to UNIX workstations. The expert system utilizes a complete gamma library with over 2600 nuclides and 80,000 lines, and a rule base of about fifty criteria including energies, relative peak intensities, genesis modes, half lives, parent-daughter relationships, etc. The rule base is furthermore extensible by the user. This is not an original contribution but a somewhat updated version of papers and reports previously published elsewhere. (author)