ISSN:0049-8246    

DOI:10.1002/xrs.1300180202

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe Armstrong–Buseck correction for absorption effects in electron probe x‐ray microanalysis of particles considers seven specific particle shapes, and for these geometries exact correction equations are used. This procedure implies that the analyst has to associate the particle to be analysed with a certain particle type; an arbitrary relative thickness is sometimes assumed. A theoretical study was made of this absorption correction as a function of the particle composition, type and thickness for micrometre‐sized particles. It appears that a correct choice of the particle type is critical. However, when the analytical results are normalized to 100%, the differences between the models are much less pronounced, and it is justified to assume a spherical model in all

ISSN:0049-8246    

DOI:10.1002/xrs.1300180203

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

年代:1989

数据来源: WILEY

摘要:

AbstractAn evaluation of the x‐ray fluorescence analysis of light elements (B, C, N and O) using synthetic multilayers and a conventional x‐ray spectrometer has been conducted. It is shown that effective measurements of long‐wavelength x‐rays can be made by using properly selected synthetic multilayers. For both B and C K radiations the Ni/C (2d= 158.8 Å) multilayer has the highest reflectivities, whereas the V/C (121.8 Å) and the W/Si (55.4 Å) multilayers have the best resolving powers. For N and O K radiations, the W/Si (80.2 and 55.4 Å) multilayers are preferred. The 80.2 and 55.4 Å W/Si multilayers produce the highest intensity and resolving power, respectively. The detection limits of the light elements using the multilayers have also been calculated, and it is shown that levels as low as 0.02% are achievable for the carbon and oxygen analyses using the Ni/C and W/Si multilayers,

ISSN:0049-8246    

DOI:10.1002/xrs.1300180204

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe Barnhart pulse pile‐up and dead time correction method is used by a number of manufacturers of energy‐dispersive x‐ray analysers. This method may provide inadequate correction at moderately high count rates and/or in the presence of low‐energy x‐ray peaks. A correction scheme is proposed to overcome these difficulties and its effectiveness is illustrated by the analysis of several homogeneous mineral samples of well established co

ISSN:0049-8246    

DOI:10.1002/xrs.1300180205

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe basic definitions of spectral resolution are considered. To the authors' knowledge, the most complete com‐pilation of data on the spectral resolution of different elements of spectrometers is given, with careful comparison

ISSN:0049-8246    

DOI:10.1002/xrs.1300180206

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

年代:1989

数据来源: WILEY

摘要:

AbstractA method was developed to determine automatically sample positions and correct peak intensities for sample positional variations in x‐ray fluorescence (XRF) analysis. Small shifts in Compton backscatter peak energy are accurately measured in the spectrum and used to compute the mean scatter angle, from which the effective scatter position is determined. New equations were derived to express fluorescent and scatter positions within samples, and to correct peak intensities for geometry variations in a sample of arbitrary thickness, position and composition. The method was validated with an energy‐dispersive XRF system with secondary excitation. With thin samples, the method corrected intensity errors of up to 69% to within 2%, and with samples of intermediate thickness it corrected errors of up to 83% to within 1.7%. The method is important in quantitative fundamental parameter calculations, such as the CEMAS method, which otherwise define the sample to lie in a pre‐determined

ISSN:0049-8246    

DOI:10.1002/xrs.1300180207

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

年代:1989

数据来源: WILEY

摘要:

AbstractIt was shown that x‐ray fluorescence is very suitable for following changes in trace element concentrations in the hair of pregnant women. Two hundred hair samples were analysed, mean concentrations for Cr, Mn, Fe, Cu and Zn were evaluated quarterly and their distribution according to weeks of pregnancy was determined. Possibilities of using longitudinal hair analysis with the purpose of following the concentrations of some particular microelements in the course of pregnancy are discusse

ISSN:0049-8246    

DOI:10.1002/xrs.1300180208

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

年代:1989

数据来源: WILEY

摘要:

AbstractCoster–Kronig processes are radiationless transitions in which an inner‐shell vacancy is transferred from one subshell of an atom to another that is less tightly bound, both belonging to the same principal shell. Experimental measurements were carried out on a few elemental samples to examine the effect of Coster–Kronig transitions on fluorescence cross‐sections for the Lα x‐ray line using 22.6 keV Ag K x‐rays for excitation. Absolute values of Lα cross‐sections were also calculated with incorporation of the enhancement due to the Coster–Kronig effect for the elements in the range 41 ≤Z≤ 92 at the same excitation energy. A windowless Si(Li) detector system with an energy resolution of 145 eV at 6.4 keV x‐ray energy was used. Thin‐film samples were employed to minimize the self‐absorption effect. Reasonably good agreement was observed between the e

ISSN:0049-8246    

DOI:10.1002/xrs.1300180209

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

年代:1989

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300180210

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

年代:1989

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300180211

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

年代:1989

数据来源: WILEY