ISSN:0049-8246    

DOI:10.1002/xrs.1300140102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractParticle size effects constitute a major source of error in the x‐ray fluorescence of granular material. Different models have been proposed to account for the influence of particle size on the characteristic x‐ray intensity leaving the sample. Important points in these models are the granular distribution from each grain. Berryet al.proposed a model which is in reasonable agreement with experimental values. In this work, fluorescent intensity calculations for a cubic particle with different geometries were carried out. The intensity values obtained through this model were compared with the Berryet al.model. There is better agreement with the experimental values when the expression obtained is used in order to find the total fluorescent intensity using heterogeneous samples consisting of fluorescent and non‐fluorescent components of particle

ISSN:0049-8246    

DOI:10.1002/xrs.1300140103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractTechniques for analysing light elements by energy‐dispersive spectrometry are discussed and a new approach is proposed. Firstly, a method for predicting the x‐ray continuum level is developed. It is based on the use of a reference standard and, unlike other methods, is accurate below 1.5 ke V. When combined with methods for dealing with spectrum artefacts, this approach allows the calculation of background levels down to 0.1 ke V. Attention is then given to the problem of overlap, which is particularly important in light element analysis. Various methods for deconvolution of peaks are considered and a technique is adopted based on least‐squares fitting of standard peak profiles. The effects of count statistics and computational accuracy on the final results are discussed. Some practical overlap situations are examined to discover the level of accuracy which can be exp

ISSN:0049-8246    

DOI:10.1002/xrs.1300140104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractExperimental mass absorption coefficients on thin‐layer samples deposited on membrane disc filters, consisting of mixtures of cellulose acetate and cellulose nitrate, were determined from the attenuation of a reflection of the crystalline material supporting the membranes. These mass absorption coefficients were used to carry out a quantitative x‐ray diffraction analysis on the same thin samp

ISSN:0049-8246    

DOI:10.1002/xrs.1300140105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe difficulty of identifying unconverted oxide phases, present in synthetic clay minerals, by classical techniques is discussed. It is shown that scanning electron microscopy, combined with the x‐ray microprobe, is very effective in such a study. Some representative micrographs of oxide phases in a synthetic vermiculite are presente

ISSN:0049-8246    

DOI:10.1002/xrs.1300140106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe K and L x‐ray emission intensities per 100 disintegrations have been calculated for some radionuclides using the latest adopted data for gamma‐ray intensities, electron capture and internal conversion coefficients for the parent nuclides, fluorescence yield values, Coster–Kronig transition probabilities, average total number of primary L shell vacancies produced in the decay of K shell vacancies and emission rates for various shells and subshells for the daughter nuclei. The results are in good agreement with theoretical and experimental values for the K x‐ray intensities. There are no experimental results available to compare with the present calculations for the L x‐ray intensities; however, there is a marked discrepancy in the Lα and Lβ intensities available on the basis of theoretica

ISSN:0049-8246    

DOI:10.1002/xrs.1300140107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractA series of 12 correction algorithms for quantitative XRF analysis have been compared. The algorithms are applied to intensities, calculated by the NRLXRF program for hypothetical binary, tertiary and one more complex alloy. The influence coefficients are determined by a least‐squares procedure. It is shown that, when both enhancement and absorption occur, at least a two‐coefficient model is necessary and for more complex samples cross‐effect terms reduce the maximum errors substant

ISSN:0049-8246    

DOI:10.1002/xrs.1300140108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractQuantitative interpretation of EPMA measurements was required for the construction of the Fe–Sn–C phase diagram. This involved the conversion of measured x‐ray intensities into concentrations, which is difficult for a light element (such as C) being present among heavier elements (Fe and Sn). To meet this problem, firstly the various intensity–concentration conversion methods from the literature have been studied and are briefly surveyed. The Claisse–Quintin relation with constant influence coefficients was selected as the algorithm for multiple regression purposes, which was applied to reference standard data. Calibration functions are obtained for Sn and C, which are used in a simple iteration procedure. This procedure has been used for the conversion of Sn and C x‐ray intensities into concentrations. The method shows a relative accuracy

ISSN:0049-8246    

DOI:10.1002/xrs.1300140109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractA presentation of fluorescence yields, ωKand ω L 3, in terms of dependence onZis developed from theory, valid for x‐ray excitation by electrons, from literature data and from experiments. The results\documentclass{article}\pagestyle{empty}\begin{document}$$\omega _{\rm K} = 3.3704 \times 10^{ - 1} - 6.0047 \times 10^{ - 2} Z + 3.3133 \times 10^{ - 3} Z^2 - 3.9251 \times 10^{ - 5} Z^3$$\end{document}and\documentclass{article}\pagestyle{empty}\begin{document}$$\omega _{{\rm L}_3 } = 4.4100 \times 10^{ - 2} - 4.7559 \times 10^{ - 3} Z + 1.1494 \times 10^{ - 4} Z^2 - 1.8594 \times 10^{ - 7} Z^3$$\end{document}are a contribution to computer‐supported quantitative x‐r

ISSN:0049-8246    

DOI:10.1002/xrs.1300140110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300140111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY