ISSN:0049-8246    

DOI:10.1002/xrs.1300230402

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

年代:1994

数据来源: WILEY

摘要:

AbstractSoil samples from 40 different sampling points in the Aydin Basin were analysed and the distributions of Ti, Cr, Mn, Cu, Zn, Sr, Zr, Rb, Ba and Ce were investigated by energy‐dispersive x‐ray fluorescence spectrometry. Two annular sources,238Pu (10 mCi) and241Am (30 mCi) and two detectors, Si(Li) and HPGe, were used. The fundamental parameter technique was adopted for quantitative analysis of elements. The concentrations of Cr, Zr, Zn and Ce were found to be higher than those corresponding to the mean chemical composition of the lithosph

ISSN:0049-8246    

DOI:10.1002/xrs.1300230403

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

年代:1994

数据来源: WILEY

摘要:

AbstractAn energy‐dispersive x‐ray fluorescence (EDXRF) apparatus using a radioisotope source with a secondary target (241Am–Mo) and a Si(Li) x‐ray spectrometer was used to measure the Cu, Sr and Bi contents of thin (100 μg cm−2) films sputtered on to MgO. The results were found to be in excellent agreement with those obtained from MeV Rutherford backscattering (RBS) analysis of the same films. The calibration of the EDXRF apparatus was done by measuring x‐ray intensities excited in thin sol‐gel films of known Cu, Sr and Bi content, as given by the accurately known chemical solutions from which the sol‐gel films were prepared. The experimental calibration constants were in excellent agreement with the theoretical values calculated using a thin‐film equation, which assumes that characteristic x‐ray absorption and secondary excitation are negligible, and the publish

ISSN:0049-8246    

DOI:10.1002/xrs.1300230404

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

年代:1994

数据来源: WILEY

摘要:

AbstractAn x‐ray fluorescence method was developed for the determination of both trace and major elements in environmental samples that are primarily of geochemical origin. For analysis, unweighed finely pulverized sample material is lightly compressed to a mass thickness between 0.1 and 0.4 g cm−2. The method utilizes the relative intensities of two incoherent and one coherent scattered excitation radiation to ascertain the sample mass thickness and the photoelectric cross‐section of the sample for the excitation radiation. This information is employed to calculate matrix absorption and enhancement effect corrections required for the individual element determinations. The intensity of one of the incoherently scattered radiations serves as an internal standard for all of the element determinations. The capability of the method has been demonstrated with three US National Institute of Standards and Technology reference materials. The concentrations of sixteen trace elements (Mn, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th) and four major elements (K, Ca, Ti, and Fe) were determined from one x‐ray spectrum which was acquired over a 1000 s counting i

ISSN:0049-8246    

DOI:10.1002/xrs.1300230405

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

年代:1994

数据来源: WILEY

摘要:

AbstractGeometrical effects occur when primary x‐rays irradiate a mineral inclusion which lies close to the boundary between it and a surrounding mineral having a different chemical composition. An investigation of two types of near‐edge effects was performed in the case when x‐ray microfluorescence is applied for analysis. For zinc sulfide in calcium carbonate and for arsenopyrite in serpentine, the increase in measured characteristic x‐ray intensity near the boundary is 15‒25%. Analytical mathematical expressions were developed to correct for such effects and the calculated results are in good agreement with measur

ISSN:0049-8246    

DOI:10.1002/xrs.1300230406

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

年代:1994

数据来源: WILEY

摘要:

AbstractBy applying monoenergetic excitation in total reflection x‐ray fluorescence analysis, the quantitative analysis can be further simplified since fundamental parameters from tables can be used for the calculation of elemental sensitivities. Establishing calibration graphs experimentally by measuring multielement standards is no longer necessary. Advantages of monoenergetic excitation are discusse

ISSN:0049-8246    

DOI:10.1002/xrs.1300230407

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

年代:1994

数据来源: WILEY

摘要:

AbstractA mathematical model for the estimation of the relative intensities of the escape peaks in HgI2detectors is presented. Comparison of calculated results with experimental values for various x‐ray energies shows satisfactory agreement. The method can be used to evaluate directly the sensitive thickness of an HgI2detector through the escape to total peak intensity rati

ISSN:0049-8246    

DOI:10.1002/xrs.1300230408

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

年代:1994

数据来源: WILEY

摘要:

AbstractSome complex cases of EDXRF spectrometry for heavy element determinations are considered. The main problem in all these cases is the determination of the elements of interest at low concentrations in the presence of absorbing and interfering matrix elements at high concentrations. One example deals with the reduction of the detection limits for the determination of rhenium in copper–lead polymetallic ores and concentrates, when the rhenium L‐series radiation of low intensity is used. A linear dependence of the analytical parameter for rhenium concentrations in the range 0.5‐30 ppm is obtained. Different types of spectrometry for characteristic radiation of K‐series of the elements from rare earths to lead with detection limits from 10 to 0.1 ppm are considered. Some applications of annular radioisotope sources as an alternative to x‐ray tubes are inv

ISSN:0049-8246    

DOI:10.1002/xrs.1300230409

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe method of synchrotron radiation XRF applied to high‐temperature superconducting films can be used for the measurement of the compositions of different compounds of the same element or of the changes in the stoichiometry in the process of thin‐film production. An important advantage of the method is that it possesses very low detection limit (down to 5 × 1013atoms cm−2) and allows a wide range of film thicknesses to be me

ISSN:0049-8246    

DOI:10.1002/xrs.1300230410

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

年代:1994

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300230411

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

年代:1994

数据来源: WILEY