TY - JOUR A1 - Alvisi, M. A1 - Blome, M. A1 - Griepentrog, Michael A1 - Hodoroaba, Vasile-Dan A1 - Karduck, P. A1 - Mostert, M. A1 - Nacucchi, M. A1 - Procop, Mathias A1 - Rohde, M. A1 - Scholze, F. A1 - Statham, P. A1 - Terborg, R. A1 - Thiot, J.-F. T1 - The Determination of the Efficiency of Energy Dispersive X-Ray Spectrometers by a New Reference Material JF - Microscopy and microanalysis N2 - A calibration procedure for the detection efficiency of energy dispersive X-ray spectrometers (EDS) used in combination with scanning electron microscopy (SEM) for standardless electron probe microanalysis (EPMA) is presented. The procedure is based on the comparison of X-ray spectra from a reference material (RM) measured with the EDS to be calibrated and a reference EDS. The RM is certified by the line intensities in the X-ray spectrum recorded with a reference EDS and by its composition. The calibration of the reference EDS is performed using synchrotron radiation at the radiometry laboratory of the Physikalisch-Technische Bundesanstalt. Measurement of RM spectra and comparison of the specified line intensities enables a rapid efficiency calibration on most SEMs. The article reports on studies to prepare such a RM and on EDS calibration and proposes a methodology that could be implemented in current spectrometer software to enable the calibration with a minimum of operator assistance. KW - Energy dispersive X-ray spectrometry KW - Standardless analysis KW - X-ray detectors KW - Detection efficiency KW - Spectrometer calibration PY - 2006 DO - https://doi.org/10.1017/S1431927606060557 SN - 1431-9276 SN - 1435-8115 VL - 12 IS - 5 SP - 406 EP - 415 PB - Cambridge University Press CY - New York, NY AN - OPUS4-13135 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Procop, Mathias A1 - Scholze, F. T1 - Synchrotron Radiation for the Characterization of Energy Dispersive X-ray Spectrometers JF - Microscopy and microanalysis KW - Röntgenspektroskopie KW - Detektoren KW - Elektronenstrahl-Mikroanalyse KW - ESMA KW - EPMA KW - Röntgenfluoreszenzanalyse KW - RFA KW - XRF PY - 2004 DO - https://doi.org/10.1017/S1431927604880152 SN - 1431-9276 SN - 1435-8115 VL - 10 IS - 2 SP - 98 EP - 99 PB - Cambridge University Press CY - New York, NY AN - OPUS4-3720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Procop, Mathias A1 - Scholze, F. T1 - Measurement of detection efficiency and response functions for an Si(Li) x-ray spectrometer in the range 0.1-5 keV JF - X-ray spectrometry N2 - Efficiency and response functions were determined for a modern commercial energy-dispersive x-ray spectrometer in the photon energy range 0.1-5 keV using dispersed and undispersed synchrotron radiation. The spectrometer was equipped with an Si(Li) detector crystal, a thin-film window and a digital pulse processor. Monochromatized synchrotron radiation from the PTB VUV radiometry beamline at the electron storage ring BESSY was used for the absolute determination of the detection efficiency with a typical relative uncertainty of 1-2% in the photon energy range 0.1-1.5 keV by direct comparison with calibrated photodiodes. At higher photon energies, the efficiency was found by comparison of the measured and calculated undispersed synchrotron radiation spectrum. The absolute intensity of the synchrotron radiation was known with a relative uncertainty of less than 1%. In the overlapping region, the results from the two independent experiments are in full agreement. The energy dependence of the measured efficiency can be explained only with a detector model assuming that there is no dead layer. A simple model for the effect of incomplete charge collection (ICC) was applied to describe the measured response functions. Consequences of the ICC such as broadening and shift of low-energy peaks and redistribution of counts around 1.84 keV are explained with the model, in accordance with the experimental results. PY - 2001 DO - https://doi.org/10.1002/xrs.472 SN - 0049-8246 VL - 30 IS - 2 SP - 69 EP - 76 PB - Wiley CY - Chichester AN - OPUS4-1120 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Scholze, F. A1 - Procop, Mathias T1 - High-accuracy calibration of energy-dispersive detectors using undispersed and monochromatized radiation T2 - BESSY highlights - annual report 2003 PY - 2004 UR - http://www.helmholtz-berlin.de/media/media/oea/web/pr_webseite/druckschriften/berichte/bessy/annualreport2003.pdf#page=14 SN - 0179-4159 SP - 14 EP - 16 PB - Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung CY - Berlin AN - OPUS4-4188 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholze, F. A1 - Procop, Mathias T1 - Detection efficiency of energy-dispersive detectors with low-energy windows JF - X-ray spectrometry N2 - Energy dispersive X-ray spectrometry offers the opportunity for fast composition determination of specimens by X-ray fluorescence or electron probe microanalysis. For fundamental parameter based quantification, the knowledge of the detection efficiency of the spectrometer is essential. At low energies the efficiency is strongly influenced by X-ray absorption in the radiation entrance window. State-of-the-art windows consist of polymer foil containing C, N, and O, coated with Al and in some cases with a special B compound. The foil is supported by a Si grid to withstand the atmosphere pressure. The absorption of all these components must be known to describe the detection efficiency. The transmittance of three types of widely used commercial windows has been measured. Transmittance curves have been fitted by analytical expressions using tabulated mass absorption coefficients. Because tabulated mass absorption coefficients do not consider near edge effects, there are strong deviations between measured and calculated transmittance below 0.6 keV. It is proposed to model the spectrometer efficiency by the measured window transmittance and calculated absorptions from front contact and possible contaminations. This reduces the number of unknown parameters drastically. PY - 2005 DO - https://doi.org/10.1002/xrs.859 SN - 0049-8246 VL - 34 IS - 6 SP - 473 EP - 476 PB - Wiley CY - Chichester AN - OPUS4-11936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scholze, F. A1 - Procop, Mathias T1 - Response function of energy dispersive semiconductor X-ray detectors - a physical model T2 - European Conference on Energy Dispersive X-Ray Spectrometry, EDXRS-2000 T2 - European Conference on Energy Dispersive X-Ray Spectrometry, EDXRS-2000 CY - Kraków, Poland DA - 2000-06-18 PY - 2000 AN - OPUS4-6141 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rackwitz, Vanessa A1 - Krumrey, M. A1 - Laubis, C. A1 - Scholze, F. A1 - Hodoroaba, Vasile-Dan T1 - New reference and test materials for the characterization of energy dispersive X-ray spectrometers at scanning electron microscopes JF - Analytical and bioanalytical chemistry N2 - Checking the performance of energy dispersive X-ray spectrometers as well as validation of the results obtained with energy dispersive X-ray spectrometry (EDX) at a scanning electron microscope (SEM) involve the use of (certified) reference and dedicated test materials. This paper gives an overview on the test materials mostly employed by SEM/EDX users and accredited laboratories as well as on those recommended in international standards. The new BAM reference material EDS-CRM, which is currently in the process of certification, is specifically designed for the characterization of EDS systems at a SEM through calibration of the spectrometer efficiency in analytical laboratories in a simple manner. The certification of the spectra by means of a reference EDS is described. The focus is on the traceability of EDS efficiency which is ensured by measurements of the absolute detection efficiency of silicon drift detectors (SDD) and Si(Li) detectors at the laboratory of the PTB using the electron storage ring BESSY II as a primary X-ray source standard. A new test material in development at BAM for testing the performance of an EDS in the energy range below 1 keV is also briefly presented. KW - EDX KW - EDS KW - Performance check KW - SEM KW - Test materials KW - Spectrometer efficiency PY - 2015 DO - https://doi.org/10.1007/s00216-014-8242-5 SN - 1618-2642 SN - 1618-2650 VL - 407 IS - 11 SP - 3045 EP - 3053 PB - Springer CY - Berlin AN - OPUS4-33025 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -