ISSN:0049-8246    

DOI:10.1002/xrs.1300050102

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe position, shape and the extended fine structure of the cobalt K absorption discontinuity have been studied in the pure metal and in its four chalcogenides, CoO, CoS, CoSe and CoTe, using a forty centimetre diameter bent crystal X‐ray spectrograph. It has been found that the discontinuity shifts towards the high energy side in the chalcogenides and that the chemical shift ΔEdepends upon the effective ionic charge on the absorbing atom. The fine structure within the main discontinuity is discussed on the basis of band structure and molecular orbital diagram, while the extended fine structure is interpreted on Lytle's theory. The results obtained throw light on the chemical bonding prevalent in these compoun

ISSN:0049-8246    

DOI:10.1002/xrs.1300050103

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

年代:1976

数据来源: WILEY

摘要:

AbstractBei geeigneter Wahl der Koeffizienten ist es Möglich, die bekannte hyperbolische Gleichung für die Röntegenspektral‐analyse des Zweistoffsystems auch im Gebiet des Korngrößen‐einflusses beizubehalten. Damit wird die experimentelle Bestimmung und Handhabung der Korngrößenparameter wesentlich vereinfacht, wie an Hand von Literaturdaten belegt wird; insbesondere ergibt sich ein Weg, den Korngrößeneinfluß von anderen Einflußfaktor

ISSN:0049-8246    

DOI:10.1002/xrs.1300050104

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

年代:1976

数据来源: WILEY

摘要:

AbstractThin windows for X‐ray spectrometer flow counters can be produced by stretching unorientated polypropylene film. A piece of the stretched film is clamped into a holder and pressed onto a copper ring made from thin copper sheeting. The mounted window is then suspended in a high vacuum coating unit and flashed with aluminium to a thickness of approximately 20 n

ISSN:0049-8246    

DOI:10.1002/xrs.1300050105

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

年代:1976

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300050113

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

年代:1976

数据来源: WILEY

摘要:

AbstractWith the appropriate excitation, a specimen will emit an X‐ray spectrum where the characteristic line intensities are strongly dependent on the elemental composition. The measurement of these intensities thus affords a method of accurate quantitative elemental analysis. A digitized record of the spectrum may be obtained using a lithium drifted silicon detector, associated electronics and some storage medium. The recorded data is the original spectrum convoluted by the appropriate instrumental function. This paper describes several procedures which may be applied to this data to obtain accurate estimates of the individual X‐ray line intensities, mainly with reference to the spectra obtained by electron excitation of thick specimens. The choice of a particular procedure depends on the quality of the data acquistion system, and the likely systematic errors which have been calculated for illustrative examples with special reference to the effects of drift and resolution changes in the electronics. Background subtraction techniques involving interpolation, extrapolation and filtering are discussed, together with methods for deconvolution of overlapping peaks, in particular least squares regression. A versatile new procedure, iterative stripping, is presented which simultaneously accomplishes background subtraction and peak deconvolut

ISSN:0049-8246    

DOI:10.1002/xrs.1300050106

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

年代:1976

数据来源: WILEY

摘要:

AbstractEleven international standards [U.S.G.S. Standards. G‐2, GSP‐1, AGV‐1 and BCR‐1; C.R.P.G. standards: GA, GH, BR and Mica‐Fe; A.N.R.T. standard: DR‐N; G.S.J. standards: JG‐1 and JB‐1] have been analysed by X‐ray fluorescence for niobium and yttrium. Coefficients for full matrix effect correc

ISSN:0049-8246    

DOI:10.1002/xrs.1300050107

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

年代:1976

数据来源: WILEY

摘要:

AbstractA method for the conversion of X‐ray intensities to composition is given. The method is based on the Lachance‐Traill equation which uses empirical inter‐element correction coefficients. The coefficients are treated as ‘sliding constants’ the values of which depend on the relative concentrations of the analyte and the interfering elements. Values for the coefficients are calculated over wide concentration ranges using the theoretical equations of Sherman. The calculated coefficients are adjusted empirically to achieve high accuracy.Only the measured X‐ray intensities from the sample and a single standard are required for an analysis. Final results are obtained by solving a set of simultaneous linear equations. Results of analyses of high alloy steels containing Cr, Ni, Mn, Mo, Cu, Si, Ti, Cb and Fe are given to illustrate the accuracy of

ISSN:0049-8246    

DOI:10.1002/xrs.1300050108

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

年代:1976

数据来源: WILEY

摘要:

AbstractDepth distributions of X‐ray production by electrons in the energy range of six to fifteen key have been measured for Si and Cu characteristic X‐rays in matrices of Al, Ni, Ag and Au. Corrections from these curves show that the modified Philibert absorption correction predicts the wrong dependence on matrix atomic number at these low electron energies, while the Duncomb and Reed atomic number correction shows too strong a dependence on atomic number. The curves should be valuable for comparison with both theoretical and empirical models for quantitative analysis at low energ

ISSN:0049-8246    

DOI:10.1002/xrs.1300050109

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

年代:1976

数据来源: WILEY

摘要:

AbstractBetween adjacent major element absorption edges, background intensities at differing wavelength positions were found to be related linearly. Also, background intensity at any position is linearly related to the reciprocal of the mass absorption coefficient for any wavelength between the absorption edges.The method presented here allows for the determination of background, as well as mass absorption coefficient, by a single measurement at an interference‐free background position (which can be the Compton scatter ‘peak’). If the mass absorption coefficient is already known, backgrounds may be calculated directly.Tests on geological materials show that, while not as accurate as conventional methods of background determination, relative accuracies of two to five percent are obtainable with a very considerable saving in time, since intensity at only one background position need be measured. Use of low dispersion high reflectivity analysing crystals, e.g. LiF(200), is possible because it is no longer necessary to attain interference‐free background positions between peaks.Furthermore, the method is ideally suited to the determination of background intensities in energy dispersive systems where spectral resolution is a problem and in multi‐channel units where only one channel need be used for the determination of both mass absorption coefficient and backgrounds for a group of trace elements.The method has been used in the low cost determination of trace elements in large numbers of geochemical prospectin

ISSN:0049-8246    

DOI:10.1002/xrs.1300050110

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

年代:1976

数据来源: WILEY