ISSN:0049-8246    

DOI:10.1002/xrs.1300170302

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

年代:1988

数据来源: WILEY

摘要:

AbstractA sample preparation method is described which permits fast and accurate wavelength‐dispersive, x‐ray fluorescence analysis of ten major oxides in carbonate rocks. The sample is first ground into a fine powder, then calcined, its loss‐on‐ignition (LOI) is determined and finally it is fused into a glass disc with lithium tetraborate at 1100°C using a 1:10 sample‐to‐flux ratio. Geological reference standards and synthetic standards are used for calibration. Matrix effects are corrected empirically using Lachance‐Traill correction algorithms. The accuracy and precision of the method were assessed by the analysis of several NBS carbonate refer

ISSN:0049-8246    

DOI:10.1002/xrs.1300170303

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

年代:1988

数据来源: WILEY

摘要:

AbstractA comparative study of the main fundamental approaches for mathematical matrix correction in x‐ray fluorescence analysis is proposed. It shows that the fundamental parameter method (Criss and co‐workers) and the competing fundamental coefficient methods (Broll, Rousseau, Tertian) are in principle equivalent, then convergent as to their results, and suffer from the same inherent limitations. Authors differ as to the ways in which these shortcomings can be overcome or greatly reduced (essentially owing to standards), and these practical aspects are also discussed in detail.The paper recalls the many advances achieved with regard to the comprehension of influence coefficients (binary coefficients, effective multicomponent coefficients, interpretation of third element effects). As a consequence, it is shown that the utilization of accuratebinarycoefficients, combined with a single fundamental parameter calculation of the relative intensities for the sample, results in a very favourable algorithm. Theoretically equivalent to the former formulations, it is definitely simpler as regards the calculation scheme, and more general with regard to the scope of applications. It is best suited for the experimental control of instrumental fact

ISSN:0049-8246    

DOI:10.1002/xrs.1300170304

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

年代:1988

数据来源: WILEY

摘要:

AbstractA method has been devised to test the correctness of relationships for computing L shell vacancies in radionuclides following electron capture and internal conversions. The average L shell fluorescence yields in eleven elements have been derived from a comparison of computed vacancies and measured subshell intensities. The validity of the relationships derived earlier is confirmed.

ISSN:0049-8246    

DOI:10.1002/xrs.1300170305

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

年代:1988

数据来源: WILEY

摘要:

AbstractTwo steps are usually used in electron microprobe correction: (1) development of a theoretical mode based on physical phenomena within pure or binary targets; and (2) simplification of certain complexities due to multi‐element samples by using average coefficients in the theoretical equations. It is proposed to use a more detailed method of estimating the general correction coefficients concerningA/Zrelationships in the absorption and ionization terms of the theoretical formulation. In the absorption formulation the factorhis taken as (1.2 ∑CiAi/Zi2)/ (1 +Ka). The value ofais given as ‐1. In the ionization relationshipM= (∑CiZi/Ai)/(1 +Kb) withb=E0/100, whereE0is the accelerating voltage in kV.K, deduced from experimental results, is given asK= ∑Ci(Zi‐Z¯), whereZ¯is the average atomic number of the target.These values are derived empirically through direct measurements on samples whose correction properties induce normally strong analytical errors: oxides with 11 ⩽Z⩽ 14 analysed with

ISSN:0049-8246    

DOI:10.1002/xrs.1300170306

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

年代:1988

数据来源: WILEY

摘要:

AbstractA theoretical approach to quantitative x‐ray fluorescence analysis of multicomponent surface layers is described. It includes both the determination of the primary energy distribution of the tube and the calculation of the x‐ray intensities according to the fundamental parameter method. The effects of several inaccuracies, such as those from the primary distribution, from the treatment of secondary excitation and from the analytical representation of attenuation cross‐sections, are discussed in detail. Their influence on the XRF intensities was studied theoretically and compared with experimental data for a wide variety of well defined multilayer systems. The final accuracy of the theoretical calculations allows one to dispense with calibration reference standards in practical analytical

ISSN:0049-8246    

DOI:10.1002/xrs.1300170307

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

年代:1988

数据来源: WILEY

摘要:

AbstractA method is described for the determination of angular positions of maxima in an x‐Ray fluorescence spectrum registered by step scanning. The cases of single and overlapping maxima were investigated. For each maximum the angular interval was determined, containing all lines which may be the cause of its emissio

ISSN:0049-8246    

DOI:10.1002/xrs.1300170308

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

年代:1988

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300170309

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

年代:1988

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300170310

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

年代:1988

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300170301

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

年代:1988

数据来源: WILEY