TY - CONF A1 - Rackwitz, Vanessa A1 - Hodoroaba, Vasile-Dan T1 - Röntgenspektroskopie am REM: Von der methodischen Erweiterung zur Metrologie T2 - Institut für Chemische Technologien und Analytik, Technische Universität Wien, Seminar "Moderne Analytische Chemie" CY - Vienna, Austria DA - 2014-01-10 PY - 2014 AN - OPUS4-29958 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rackwitz, Vanessa A1 - Warrikhoff, A. A1 - Hodoroaba, Vasile-Dan T1 - Accurate determination of small spot X-ray tube spectra by means of direct measurement in a calibrated instrumental setup N2 - A calibrated instrumental setup was specially developed for the purposes of accurate measurements of absolute X-ray spectra emitted by modern micro-focus, low-power X-ray tubes. By knowing all the instrumental parameters the spectra measured with the 16 m long setup are recalculated into emitted X-ray tube spectra in photons per eV per msr per nA per s. KW - X-ray tube KW - Calibration KW - Absolute X-ray spectrum KW - Setup PY - 2014 U6 - https://doi.org/10.1039/c3ja50353d SN - 0267-9477 SN - 1364-5544 VL - 29 IS - 3 SP - 458 EP - 463 PB - Royal Society of Chemistry CY - London AN - OPUS4-30196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Marinenko, R.B. A1 - Rackwitz, Vanessa A1 - Bremser, Wolfram A1 - Unger, Wolfgang T1 - Determination of the k-values of copper-gold alloys with ED- and WD-EPMA - Results of an inter-laboratory comparison N2 - An inter-laboratory comparison organized as a pilot study (PS) has been performed under the umbrella of the Consultative Committee for Amount of Substance – Metrology in Chemistry (CCQM) / Surface Analysis Working Group (SAWG) with the objective to compare k-values measured with Electron Probe X-ray Microanalysis (EPMA) for copper-gold alloys. The k-value, defined as the ratio of the Xray photon intensity of an X-ray characteristic line of the unknown sample to the corresponding one in the reference material, is a rough estimate of the mass fraction of the respective element. Basically, the mass fractions can be calculated from the k-values after applying a matrix correction procedure, which includes empirical approaches, so that traceability gets lost. Due to its physical, measurable nature, the k-value has been selected in the present PS as the primary measurand. The mass fraction has been set as the secondary (derived) measurand. Both EDX and WDX have been employed. The WDX results and the overall comparability between the k-values obtained by EDX and WDX are still in progress. KW - Interlaboratory comparison KW - EDX KW - WDX KW - EPMA KW - K-values KW - Cu-Au alloy KW - CCQM PY - 2014 U6 - https://doi.org/10.1017/S1431927614005376 SN - 1431-9276 SN - 1435-8115 VL - 20 IS - Suppl. S 3 SP - 730 EP - 731 PB - Cambridge University Press CY - New York, NY AN - OPUS4-31338 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rackwitz, Vanessa A1 - Hodoroaba, Vasile-Dan T1 - Neue Referenz- und Testmaterialien sowie Prozeduren zur Funktionskontrolle und Spezifizierung von energiedispersiven Röntgenspektrometern (EDS) T2 - Training Course on quality Assure for traceable energy dispersive eletron probe microanalysis (ED-EPMA) CY - Berlin, Germany DA - 2014-03-28 PY - 2014 AN - OPUS4-30587 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rackwitz, Vanessa A1 - Hodoroaba, Vasile-Dan A1 - Benemann, Sigrid T1 - Spezifische Standard ArbeitsAnweisung (StAA) für die Kalibrierung und Funktionskontrolle von energiedispersiven Rötgenspektrometern (EDS) T2 - Training Course on quality Assureance for traceable energy dispersive electron probe microanalysis (ED-EPMA) CY - Berlin, Germany DA - 2014-03-28 PY - 2014 AN - OPUS4-30588 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Rackwitz, Vanessa T1 - Gaining improved chemical composition by exploitation of compton-to-rayleigh intensity ratio in XRF analysis N2 - The high specificity of the coherent (Rayleigh), as well as incoherent (Compton) X-ray scattering to the mean atomic number of a specimen to be analyzed by X-ray fluorescence (XRF), is exploited to gain more information on the chemical composition. Concretely, the evaluation of the Compton-to-Rayleigh intensity ratio from XRF spectra and its relation to the average atomic number of reference materials via a calibration curve can reveal valuable information on the elemental composition complementary to that obtained from the reference-free XRF analysis. Particularly for matrices of lower mean atomic numbers, the sensitivity of the approach is so high that it can be easily distinguished between specimens of mean atomic numbers differing from each other by 0.1. Hence, the content of light elements which are “invisible” for XRF, particularly hydrogen, or of heavier impurities/additives in light materials can be calculated 'by difference' from the scattering calibration curve. The excellent agreement between such an experimental, empirical calibration curve and a synthetically generated one, on the basis of a reliable physical model for the X-ray scattering, is also demonstrated. Thus, the feasibility of the approach for given experimental conditions and particular analytical questions can be tested prior to experiments with reference materials. For the present work a microfocus X-ray source attached on an SEM/EDX (scanning electron microscopy/energy dispersive X-ray spectroscopy) system was used so that the Compton-to-Rayleigh intensity ratio could be acquired with EDX spectral data for improved analysis of the elemental composition. PY - 2014 U6 - https://doi.org/10.1021/ac5000619 SN - 0003-2700 SN - 1520-6882 VL - 86 IS - 14 SP - 6858 EP - 6864 PB - American Chemical Society CY - Washington, DC AN - OPUS4-31179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -