scholarly journals Peak Area Consistency Evaluation in Gamma Spectrometry

2021 ◽  
Vol 253 ◽  
pp. 07002
Author(s):  
Henrik Persson ◽  
Kara Phillips
Keyword(s):  
Gamma Spectrometry ◽  
Gamma Spectroscopy ◽  
Efficiency Calibration ◽  
Complex Spectrum ◽  
Gamma Emission ◽  
Accurate Analysis ◽  
Decay Data ◽  
Peak Areas ◽  
Consistency Evaluation ◽  
Peak Area Calculation

Quantification of radionuclide activities in gamma spectrometry can be a challenging task. It depends on efficiency calibration, peak area calculation, nuclide decay data and correction factors, such as attenuation correction or true coincidence summing corrections. These quantities can present significant challenges to an accurate analysis. It is therefore desirable to have a way of assessing the quality of the radionuclide quantification that can be applied to samples with unknown activities and radionuclide compositions. A verification of the self-consistency of the analysis is one possible way of accomplishing this. In gamma spectrometry it is possible to calculate radionuclide activities using information from multiple gamma emission energies. This leads to an overdetermined system for which the solution can be used to look for inconsistencies. By calculating the recovered peak areas from the radionuclide activities and comparing these to the measured peak areas, outliers can be identified and by resolving these inconsistencies the analysis of the spectrum can be improved. This peak area consistency evaluation can be used to find incorrect shape of the efficiency calibration, missing interferences in the nuclide decay data, and point to peaks where the peak area calculation needs to be optimized. The performance of the method has been shown on a simple spectrum consisting of three radionuclides that are interfering with each other as well as a complex spectrum with unknown radionuclide composition and activities. The method will be integrated into a future version the Genie 2000 Gamma Spectroscopy Software.

Quantitative Analysis of Mixed Volatile Fluids by Raman Microprobe Spectroscopy: A Cautionary Note on Spectral Resolution and Peak Shape

1993 ◽  
Vol 47 (6) ◽  
pp. 816-820 ◽  
Author(s):  
Jeffery C. Seitz ◽  
Jill D. Pasteris ◽  
George B. Morgan
Keyword(s):  
Spectral Resolution ◽  
Quantitative Information ◽  
Peak Height ◽  
Peak Position ◽  
Accurate Analysis ◽  
Spectral Parameters ◽  
Peak Areas ◽  
Selection Of ◽  
Modest Effect

Raman analyses of fluid inclusions can yield quantitative information on composition (from peak areas and heights) and density (from peak position and width). In this study, we examine the effect of instrumental spectral resolution on the ratios of these spectral parameters, and the selection of appropriate integration limits for the determination of peak areas in the CO2-CH4-N2 system. Spectral resolution was varied from about 1 to 9 cm−1 by co-varying the widths of all spectrometer slits. Changes in resolution produced a modest effect on peak-area ratios and a significant effect on peak-height ratios. Measured peak-width ratios varied strongly as a function of the spectral resolution. In addition, we observed a moderate shift in the measured peak position of N2, which can be related to the asymmetry of the band. These results indicate that accurate analysis requires careful attention to the selection of quantification factors, especially if the selected values were derived from studies at different spectral resolutions. Another factor that can have a significant effect on the calculated compositions of CH4- and H2-bearing fluid mixtures is the band broadening that occurs with increasing pressure.

scholarly journals A generalized mathematical model for efficiency calibration of gamma detectors: Application to practical cases

2019 ◽  
Vol 34 (1) ◽  
pp. 34-46 ◽  
Author(s):  
Nikola Mihaljevic ◽  
Slobodan Jovanovic ◽  
Aleksandar Dlabac
Keyword(s):  
Gamma Spectrometry ◽  
Detection Efficiency ◽  
Computer Code ◽  
Empirical Models ◽  
Efficiency Calibration ◽  
Crucial Issue ◽  
Numerical Testing ◽  
Source Data ◽  
Semi Empirical

Efficiency calibration, i. e. determination of detection efficiency, ?p, is a crucial issue in gamma spectrometry (quantification of gamma spectroscopic measurements) with semiconductor and scintillation detectors. Comparing three possible ways to addressing the problem ? relative, absolute and semi empirical ? advantages of the latter are emphasized. Among semi empirical models, efficiency transfer using effective solid angles, ??, is sorted out and briefly elaborated. This approach reduces the problem of efficiency calibration to the determination of ??. It proved reliable and has been broadly used in practice, mainly in the form of the long existing ANGLE software. Progressing further, a generalized mathematical formula for calcu- lations is developed ? first of the kind ? offering an opportunity for advanced applications of gamma spectrometry. The formula enables unlimited flexibility in application, as it conveniently separates the source data from the detector data during the integration procedures ?? calculations). Its practicality is demonstrated for a number of typically encountered counting arrangements, as well as for some exotic ones. The relevant formulae are used in PC calculations and numerical testing is further performed so as to check the validity of the mathematical method and the computer code. Care was taken of the optimization of complex numerical procedures employed (involving fivefold numerical integration), so as to keep computation times as low as possible (in order of minutes or even seconds on ordinary PC). Results obtained are affirmative for both the method and the code. The model will be gradually incorporated into ANGLE software, thus making it readily available for routine use by gamma spectrometry community.

Mathematical efficiency calibration methods for high quality laboratory based gamma spectrometry systems

2012 ◽  
Vol 296 (2) ◽  
pp. 1045-1049 ◽  
Author(s):  
P. J. LeBlanc ◽  
F. Bronson ◽  
W. F. Mueller ◽  
W. Russ ◽  
R. Venkataraman
Keyword(s):  
Gamma Spectrometry ◽  
Efficiency Calibration ◽  
High Quality ◽  
Calibration Methods

scholarly journals A mathematical model of semiconductor detector gamma-efficiency calibration for rectangular cuboid (brick-shape) sources

2018 ◽  
Vol 33 (2) ◽  
pp. 139-149
Author(s):  
Nikola Mihaljevic ◽  
Slobodan Jovanovic ◽  
Aleksandar Dlabac ◽  
Mohamed Badawi
Keyword(s):  
Mathematical Model ◽  
Gamma Spectrometry ◽  
Emergency Preparedness ◽  
Construction Materials ◽  
Systematic Errors ◽  
Efficiency Calibration ◽  
Semiconductor Detectors ◽  
Gamma Energy ◽  
Activity Measurements ◽  
The Cost

Rectangular cuboid (rectangular parallelepiped), i. e., brick-shape sources are not really common in general gamma-spectrometry practice with semiconductor detectors, where axially symmetrical sources prevail. However, in some particular applications, like radioactivity control of food or construction materials (for monitoring and regulatory purposes, radiological emergency preparedness, or in the aftermath of nuclear accidents), brick shapes may come to significance. In order to simplify routine/repetitive low activity measurements, it is easier and more practical to measure the radioactivity of these sources as such, i. e., without transforming them into ?regular? (cylindrical or Marinelli) shapes. This saves considerably on laboratory time, workforce and consumables-thus eventually cutting the cost of analysis and improving laboratory performance. In addition, the accuracy of the analytical results is enhanced, as the possibilities for systematic errors are reduced. To that aim, in the present work a mathematical model for brick-source efficiency calibration is developed. The well known, accurate and widely used efficiency transfer principle is applied, together with detector efficiency calculations based on the effective solid angle W concept. For testing purposes, comparisons are made with previously developed and well established mathematical models for detector calibration involving axially symmetrical sources (point, disc, and cylinder). Namely, brick sources were regarded as a sort of interpolation between the outer and inner cylinder of the same height, for which efficiencies could be accurately determined by numerical calculations (software ANGLE). For the sake of completeness, the equivoluminous cylinders were taken into account as well. Brick shape sources of various sizes and proportions were examined; when approaching zero dimensions, results were obtained for point and disc sources. All calculations were performed in gamma energy range 50-3000 keV. The results are consistent and logical, with no discrepancies indicating bugs or systematic errors-thus convincingly confirming the fundamentality and reliability of the model. The model is about to be incorporated into ANGLE software as a new functionality, so as to make it available to gamma spectrometry community.

scholarly journals Developing a software for self-absorption correction for gamma spectrometry of soil and water samples based on MCNP5 Monte Carlo simulations

2020 ◽  
Vol 17 (2) ◽  
pp. 13
Author(s):  
Eliyeh Zamani ◽  
Sedigheh Sina ◽  
Reza Faghihi ◽  
Banafshe Zeinali-Rafsanjani
Keyword(s):  
Monte Carlo ◽  
Environmental Samples ◽  
Hpge Detector ◽  
Gamma Spectroscopy ◽  
Efficiency Calibration ◽  
Monte Carlo Code ◽  
Detector Efficiency ◽  
Calibration Curves ◽  
Absorption Correction ◽  
Soil And Water

Gamma spectroscopy using HPGe is one of the most effective methods in determining the concentration of gamma emitting radionuclides in environmental samples. The purpose of this study is obtaining the efficiency calibration curves for the HPGe detector using MCNP5 Monte Carlo code, and designing appropriate software for correction of self-absorption caused by changes in density, height, and geometry of different samples. For this purpose the detector was simulated using MCNP5 Monte Carlo code, and the detector calibration curves were obtained for different geometries and heights, and appropriate software was designed for efficiency calibration. The results obtained in this study, show that changing the height, geometry, and density of the samples have significant effects on the detector efficiency because of the changes in self-absorption of the samples. Comparison of the self-absorption correction using the software, and the results of simulations show that designed software can predict the calibration curves for the new samples in different energies with error much less than 1%.

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