ISSN:0049-8246    

DOI:10.1002/xrs.1300190402

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

年代:1990

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300190403

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

年代:1990

数据来源: WILEY

摘要:

AbstractIt is shown, using measurements on certain zinc minerals, that the Lα emission of transition metals can be affected as follows. First, the band shape is often changed in the range of the satellite emission which implies, for data acquisition, the use of the total band area instead of the measurements at the peak maximum. Second, the physical process of self‐absorption of Lα photons (here, the absorption of Zn Lα in Zn) depends on the nature of the specimen (metal, semiconductor, insulator), In EPMA, the corresponding theoretical parameter, which is the mass self‐absorption coefficient, may be then changed between an unknown and standard, despite the assumption of constancy in matrix‐effect correction models. Both phenomena are correlated because of their strong dependence on the electronic structure of the M5level, which can be modified in poor conducting materials by the presence of holes. The choice of suitable standards is then crucial in order to perform accuratek‐ratio me

ISSN:0049-8246    

DOI:10.1002/xrs.1300190404

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe K‐shell correction to stopping power developed by Livingston and Bethe and its influence on electron microprobe analysis are discussed. A comparison among models for the mean excitation energyJgiven by different workers was made. Two new expressions forJas a function of atomic numberZare suggested for the microanalysis of samples with K‐shell effects: one from stopping power experimental data and the other one from Chu and Powers' theoretical calculations. Livingston and Bethe's K‐shell correction was applied to both new m

ISSN:0049-8246    

DOI:10.1002/xrs.1300190405

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe concept, design, characterization and operation of an apparatus for low‐energy x‐ray fluorescence are described. This system utilizes commercially available components in a novel arrangement. An Al K x‐ray source, an ultra‐thin‐windowed Si(Li) detector and an ion gun for sputter cleaning were combined to perform analyses for elements with atomic number Z ⩾ 6. Pairs of slit collimators placed between the specimen and the x‐ray detector defined the area analyzed. The system configuration permitted analyses over areas with a variety of dimensions (0.4–22 mm). Distinction between surface and bulk signals was possible using the sputter‐cl

ISSN:0049-8246    

DOI:10.1002/xrs.1300190406

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

年代:1990

数据来源: WILEY

摘要:

AbstractQuantitative analysis for oxygen on the surface and in the bulk of materials has been demonstrated using an energy‐dispersive x‐ray fluorescence system. The system consists of an Al K x‐ray source, an ultra‐thin‐windowed Si(Li) detector and an ion gun for sputter cleaning. Sputter cleaning was required to distinguish between surface and bulk O K x‐ray signals. Since beryllium has one of the lowest mass absorption coefficients for O K x‐rays, calculations and extensive measurements were made for oxygen on and in beryllium. The 3‐α detection limits were 0.22 nm of BeO on beryllium and 98 atomic parts per million (appm) of oxygen in beryllium. Measurements of surface oxides on other materials indicated detection limits of 1.9 nm of SiO2on silicon and 2.0 nm of Ta2O5on tantalum. The corresponding detection limits for oxygen in silicon and tantalum were 0.39 and 4.3 at.

ISSN:0049-8246    

DOI:10.1002/xrs.1300190407

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe fundamental or effective influence coefficients are derived from the theoretical fluorescence intensities. For a monochromatic excitation, the calculations are simplified and do not require the spectral intensity distribution of the x‐ray tube. The use of the fundamental coefficient method applied to a quasi‐monochromatic excitation is illustrated by a practical application of the analysis of stainless steel and a high‐temperature alloy. The measurements were made with an energy‐dispersive spect

ISSN:0049-8246    

DOI:10.1002/xrs.1300190408

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

年代:1990

数据来源: WILEY

摘要:

AbstractAn analytical expression was deduced for calculating the mean depth of ionization,pz, in electron probe x‐ray microanalysis. The data used were generated from previous Monte Carlo calculations for bulk targets of aluminium, titanium, iron, copper, arsenic, indium, tungsten, gold and lead at normal electron incidence for energies ranging from 10 to 40 keV. The results show that the mean depthpzdepends on the back scattering coefficient,η, the energy of the incident electron,Eo, the excitation energy of the target atoms,Ec, and the target atomic number,Z. In the case of non‐normal incidence, it is found that the ratio of the mean depthpz(α) at an angle of incidence α to the mean depthpz(0) at normal incidence varies linearly with cos α and depends only on the atomic number of the target material. The effect of the atomic number of the target on the ionization mean depth was also

ISSN:0049-8246    

DOI:10.1002/xrs.1300190409

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

年代:1990

数据来源: WILEY

摘要:

AbstractA study of the physical and practical aspects needed for a successful solid solution method for XRF analysis is presented in the light of the theory and practice of the glass‐making industry. An inexpensive manual glass disk sample preparation method is proposed that gives a well annealed disk that can be ground and polished without any losses due to breakag

ISSN:0049-8246    

DOI:10.1002/xrs.1300190410

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

年代:1990

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300190411

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

年代:1990

数据来源: WILEY