ISSN:0049-8246    

DOI:10.1002/xrs.1300100202

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

年代:1981

数据来源: WILEY

摘要:

AbstractSamples containing identical or very similar phases and differing in their contents of these can be used for calibration of a quantitative X‐ray diffraction analysis without knowing their actual mineralogical composition. The method requires that at least one major peak for each phase is well isolated and that the number of calibration samples is equal to or exceeds the number of phase

ISSN:0049-8246    

DOI:10.1002/xrs.1300100203

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

年代:1981

数据来源: WILEY

摘要:

AbstractA method of absorption correction in X‐ray diffraction (XRD) phase analysis, based on measurements of Compton scattering, is described. Compton scattering of Mo Kα was measured and Cu Kα was used for XRD analysis. Under these conditions, the method is valid for phase analysis of silicate and carbonate rocks. Quartz content was determined in 13 samples by the proposed method and the conventional method of internal standard. The two sets of results are in a good agreem

ISSN:0049-8246    

DOI:10.1002/xrs.1300100204

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe experimental evaluation of the Rhodes–Hunuer model of the particle size effect in X‐ray fluorescence analysis of ‘thin’ and monolayer samples is reported. The calculations and experiments were carried out for samples of iron oxide(Fe3O4) and copper sulphide (Cu2S) having particles of one size and a histog am distribution of particle sizes. For iron oxide particles, it was found that sticking causes a significant systematic discrepancy between the experimental results and the Rhodes–Hunter model prediction. For copper sulphide particles the model was a

ISSN:0049-8246    

DOI:10.1002/xrs.1300100205

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe calibration of an energy‐dispersive X‐ray spectrometer is calculated from published physical constants, when the geometry factor of secondary target, sample, detector is obtained experimentally and when the detection efficiency of the Si(Li) detector is calculated from such experimentally derived parameters as the thickness of cryostat window, gold surface barrier contact and silicon dead layer. The results are compared with calibrations obtained experimentally from commercial single element thin film standards obtained by vacuum evaporation and multielement standards obtained by incorporating known amounts of the elements into a thin film polymer. The results obtained from fundamental parameters agree with the experimental data to within 5

ISSN:0049-8246    

DOI:10.1002/xrs.1300100206

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

年代:1981

数据来源: WILEY

摘要:

AbstractA simple additive method, based on55Fe and109Cd source induced fluorescence in a helium environment, is presented for sulphur and lead determintion in petroleum products. Although the density of the matrix influences the X‐ray yields, the similarity of photon attenuation in water and petroleum products can be explotied. It is shown that routine system calibration can be achieved by the use of inorganic chemicals dissolved in water instead of organic additives in products. The low pressure helium flow suppresses the argon X‐rays, provides a good background region and increases the detection sensitivity for sulp

ISSN:0049-8246    

DOI:10.1002/xrs.1300100207

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

年代:1981

数据来源: WILEY

摘要:

AbstractRelative X‐ray fluorescent intensity data have been generated numerically for binary samples under mono‐chromatic excitation in those cases of absorption plus enhancement that are dealt with in this work. These data were fitted to the empirical Rasberry–Heinrich equation, keeping both coefficients different from zero, since from our numerical calculations it is shown that in most cases the best fit is achieved whenA≠ 0. Furthermore, this approach shows that a third coefficient introduced into the empirical equation improves the fitting. The aforementioned results suggest that the empirical equation could be deduced from the theoretical equation of fundamental parameters under suitable approximation. The result is an equation similar to that of Rasberry and Heinrich, from which analytical approximated coefficients are obtained. It is then possible to calculate a calibration curve using fundamental parameters

ISSN:0049-8246    

DOI:10.1002/xrs.1300100208

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

年代:1981

数据来源: WILEY

摘要:

AbstractOil film contamination of the Be window of a Si detector has been demonstrated using archival information on X‐ray intensities from calibration standards acquired over a two and a half year period. Although cleaning the window with a solvent restores sensitivity for soft radiation, recontamination can be rapid unless a small heating device is placed close to the window. A mathematical correction is suggested which avoids significant analytical errors from the effect of any contamination which may be present. It can be applied automatically by data processing software using information from the calibration standard spectru

ISSN:0049-8246    

DOI:10.1002/xrs.1300100209

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

年代:1981

数据来源: WILEY

摘要:

AbstractVarious pretreatments required for analysis of vermiculite minerals by scanning electron miscroscopy are described. It is shown that lyophilized samples exhibit more characteristic and reproducible micrographs than when simply dried in air. The mineral should e preheated in vacuum at 150°C to aviod the risk of exfoliation. In view of the fragile structure of clay minerals, polishing of the solid is to be avioded

ISSN:0049-8246    

DOI:10.1002/xrs.1300100210

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

年代:1981

数据来源: WILEY

摘要:

AbstractA systematic investigation of the chemical effects on the calcium X‐ray K emission spectra from 32 chemical compounds was carried out using a two‐crystal X‐ray spectrometer. The observed chemical shifts of the Ca Kα1,2,Kα3,4,Kβ1,3and Kβ5lines relative to the respective lines from CaF2varied in the range +0.06 to +0.30, +0.09 to +0.32, −0.06 and +1.1 to +3.2eV, respectively. A certain dependence on the nature of surrounding groups was found in these shifts. The profile changes in the Ca Kβ5and Kβ 5′bands from all compounds were discussed by subdividing them roughly into three types, depending upon their charac

ISSN:0049-8246    

DOI:10.1002/xrs.1300100211

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

年代:1981

数据来源: WILEY