ISSN:0049-8246    

DOI:10.1002/xrs.1300070302

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe design and installation of a cold trap system is described specifically with reference to its use in ameliorating analysis for low atomic number elements. This trap has been mounted aon an A.R.L. EMX instrument and its use in the analysis of carbon has been investigated. This paper also discusses the metallurgical and metallographic preparation of standards for carbon analysis along with matrix correction procedures for quantitative analysis.

ISSN:0049-8246    

DOI:10.1002/xrs.1300070303

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

年代:1978

数据来源: WILEY

摘要:

AbstractLinear and non‐linear least‐squares profile‐fitting procedures are compared in their ability to resolve severely overlapping peaks in X‐ray spectra. With linear methods, errors due to inaccuracies in peak position and width are likely to be greater than statistical errors for a spectrom with 500 K counts unless the spectrometer can maintain a temporal and count are stability of 1 eV or better. While non‐linear, iterative, procedures can accomodate changes in position and width of peaks, they are difficult to analyse therotically so simulations have been designed to examine performance. Examples are given where, despite exact knowledge of peak width and separation, the best fit in the ‘chi‐square’ sense corresponds to peak heights which are totally incorrect. Estimates of statistical error are virtually meaningless when convergence occurs to such inapprooriate minima but rather precise starting values for the unknown parameters are required to ensure convergence to a relistic solution. In view of these potential difficulties and the lack of any theoritical analysis of the instabilties introduced by statistical noise, errors in background subtraction or unsuitable parameterization of peak models, it is felt that linear method are preferable. Thus, high spectrometer stability still seems to be unavoidable if one is to exploit the availabler statistical accuracy in an

ISSN:0049-8246    

DOI:10.1002/xrs.1300070304

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

年代:1978

数据来源: WILEY

摘要:

AbstractA CGR cold cathode tube for X‐ray anlysis of very light elements has been attached to a sequential Siemens XRF spectrometer. Economic consideraions justify a rapid changeover attachment rather than the purchase of a separate spectrometer which can be applied to a few elements. The essential conceppts developed for successful integration of the attachment with the spectrometer are described. An automic activated alumina trap system to remove backstreaming oil vapours was incorporated with the existing vacuum logic. The current stabilization circuit of the generator was redesigned in order to acheive quantitative analyses. The developed attachment has competitive applicability to the quantitative analyses of magnesium and lighter elements. For magnesium the cold cathode tube achieves a large deduction in both matrix absorption effects and high order spectral interferences when compared with a typical chromium tub

ISSN:0049-8246    

DOI:10.1002/xrs.1300070305

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

年代:1978

数据来源: WILEY

摘要:

AbstractElemental X‐Ray mappings on Portland cement clinkers have been obtained using a scaning electron microscope‐energy dispersive system (SEM‐EDS). Using this method, elemental mapping of the major constituents of cement (Ca, Si, Al, Fe) can be generated in as little as 300 s, while the minor constituents(<10%) Such as Na, Mg, P, S, K yield poorer contrast mappings. The technique used and the resultant mappings obtained are disc

ISSN:0049-8246    

DOI:10.1002/xrs.1300070306

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

年代:1978

数据来源: WILEY

摘要:

AbstractIn modern geochemical laboratoriesX‐tay fluorescence spectrometry (XRFS) is a highly favoured analytical technique particularly when the need for geochemical data is relatively important. The analytical procedures currently employed involve XRFS analysis of lithium borate fused glass disc of rock samples, followed by computer generated mathematical corrections for the usual matrix effects. A significantly different procedure, free from mathematical matrix effect corrections, is presented here. After the lithium borate fusion step, the ground fusion product is dissolved by thorough mixing with an aqueous suspension, of a strong acid cation exchange resin in H+form. During the caution exchange dissolution, the cautions originally present in the sample are transfered quantitatively and uniformly to the resin pahse. The oven‐dried resin heads coated as a thin film on a strip of adhesive paper are analysed. The routine performance of the procedure is illustrated with the data accumulated on six major elements (Al, Fe, Ca, Mg, K and Ti) in five international rock reference samples during a period of one academic year. The main feature of this analytical method is the production of high quality geochemical data without any need for mathematical correcti

ISSN:0049-8246    

DOI:10.1002/xrs.1300070307

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

年代:1978

数据来源: WILEY

摘要:

AbstractIn order to determine the composition of very thin homogeneous layers of multi‐component systems, a reinterpretation of G. A. Hutchins' Method for elemental metal films was worked out. This made it theoritically possible to calibrate for the composition of complex n‐component fims by using massive standards of pure constituents as is done in the case of bulk samples. The method was supplied to very thin layers of AlNi alloys and the results are compared with those obtained by means of emission X‐ray spect

ISSN:0049-8246    

DOI:10.1002/xrs.1300070308

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

年代:1978

数据来源: WILEY

摘要:

AbstractDie Qualität eines Analysenverfahrens ist in erster Linie durch seinen Fehler gekennzeichnet, aus dem sich als weiters wichtige Kenngrössen die Unterscheidungsgrenze und die Nachweisgrenze ableiten lassen. Alle diese Fehlergrössen werden unter den Bedingungen der analytischen Praxis behandelt. Es wird ferner gezeigt, dass die vielfach gemachten idealisierten Annahmen für die gennten Fehlergrö zu Werten führen, die praktisch nicht erreichbar und daher fü die Praxis ohne Bedeutun

ISSN:0049-8246    

DOI:10.1002/xrs.1300070309

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

年代:1978

数据来源: WILEY

摘要:

AbstractA low‐energy spectrometer for the X‐ray analysis of plutonium and plutonium‐containing materials has been built. We use ultra‐thin window to maintain different pressures and contamination level in the spectrometers's sample and crystal chambers. Ultra‐thin windows are also used on the X‐ray tube and detector. Methods have been developed by which the spectrometer can analyze both metal and loose‐powder samples. Representative calibration spectra are presented for the fluorine band in polyfluoroethylene, the oxygen band in α‐Al2O3, and the carbon band in graphite. Experimental spectra are presented for the fluorine band in PuF3and for the ox

ISSN:0049-8246    

DOI:10.1002/xrs.1300070310

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

年代:1978

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300070311

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

年代:1978

数据来源: WILEY