Christina Streli

TU Wien

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TXRF with Various Excitation Sources

Advances in X-ray Analysis (1991)

P. Wobrauschek Peter Kregsamer Christina Streli R. Rieder H. Aiginger

Abstract Improving the detection limits in TXRF by optimizing the excitation conditions is the goal of this work. The properties of the exciting radiation due to spectral distribution, polarisation, intensity and energy are investigated and compared to find best conditions. Results are given from experiments performed with synchrotron radiation, Bragg polarized monoenergetic x-rays, high energy cut-off reflector in the primary beam path of a high power x-ray tube and several geometries for the sample reflector.

Reflector (photography)

Radiant intensity

Spectral power distribution

10.1154/s0376030800013112

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Citations (10)

Total reflection X-ray fluorescence analysis of low-Z elements

Spectrochimica Acta Part B Atomic Spectroscopy (1989)

Christina Streli H. Aiginoer P. Wobrauschek

X-Ray Fluorescence

Reflector (photography)

Reflection

Crystal (programming language)

10.1016/0584-8547(89)80055-2

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Citations (38)

Atomic spectrometry update—X-ray fluorescence spectrometry

Journal of Analytical Atomic Spectrometry (2012)

Margaret West Andrew T. Ellis Philip J. Potts Christina Streli Christine Vanhoof

This review demonstrates advances in XRF instrumentation, techniques and data processing algorithms published during the last year. Pixellated detectors and EDXRF imaging/mapping using a variety of materials and readout technologies have set a trend that will undoubtedly continue due to improved sensor array fabrication and readout devices that are now more widely available. Instrumental development took place at synchrotron beamlines with reports that described the measurement and data processing methodologies for use with combinations of μ-analytical techniques (μ-SRXRF, μ-XANES and μ-PIXE) that offer chemical imaging to researchers interested in spatial distribution and speciation of elements within plants and cell tissue for environmental studies and medical diagnostics. Archaeological and cultural heritage applications similarly benefit with insight of the original fabrication or subsequent alteration of artefacts. Although recent developments in hand-held instrumentation have substantially improved the capabilities of this form of XRF, advances in instrumentation continue to be reported. TXRF is a growing analytical technique with systematic studies in sample preparation, sample shape and influence of absorption on both the incident and fluorescent radiation bringing benefits for the analysis of environmental samples. A new method of elemental depth profiling has been developed and the corrosion process has been characterised with an unprecedented level of detail. A large proportion of geological studies focused on evidence for climate and environmental change over geological time periods.

Instrumentation

X-Ray Fluorescence

Profiling (computer programming)

10.1039/c2ja90045a

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Citations (39)

Determination of phosphorus and other elements in atmospheric aerosols using synchrotron total‐reflection X‐ray fluorescence

X-Ray Spectrometry (2013)

Ursula E. A. Fittschen Christina Streli Florian Meirer Matthias Alfeld

In this study, P and other low Z elements were determined in aerosol particulates from ambient air using synchrotron radiation‐induced total‐reflection X‐ray fluorescence analysis. Atmospheric transport of nutrients such as P or Si to the oceans is a key factor to marine plankton growth. Concentration of these elements in marine air masses is generally low (P < 10 ng/m 3 ). Therefore, analytical procedures enabling for low detection limits are of interest. Because particle size is strongly correlated to its origin and sedimentation, the aerosols were collected with the aid of a low‐pressure Berner impactor, which separates the aerosol particulates in nine size fractions with the smallest fraction from 15 to 30 nm. To be able to determine low Z elements, measurements were performed under vacuum conditions at the FLUO beamline at the ANKA synchrotron. An excitation energy of 3.5 keV near the P K‐edge but below the Ca K absorption edge was chosen to avoid interferences of the P K‐line with the detector escape artifact of the Ca‐K α line. The result showed P was present in concentration from 2 to 180 ng/m 3 . Detection limits were found to be generally 0.2–0.3 ng/m 3 for a collecting time of 1 h for the aerosols, which is an improvement to detection limits reported in other studies. Other elements such as S, Cl, and Si were determined as well. Si like P is a nutrient for marine plankton (diatoms). S and Cl play an important role in cloud formation, e.g. polar stratospheric clouds. Copyright © 2013 John Wiley & Sons, Ltd.

X-Ray Fluorescence

Particle (ecology)

Sedimentation

10.1002/xrs.2457

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Citations (15)

Atomic Spectrometry Update—X-Ray Fluorescence Spectrometry

Journal of Analytical Atomic Spectrometry (1996)

Andrew T. Ellis Philip J. Potts Michael V. Holmes Graham L. Oliver Christina Streli

This is the first 'stand-alone' ASU review of XRF, following its 'divorce' from mass spectrometer techniques and it is particularly appropriate to welcome new expertise contributing to this review provided by Peter Wobrauschek and Christina Streli of the Atom Institut, Vienna, and Graham Oliver and Mike Holmes of Ceram Research, Stoke-on-Trent. As in previous years, contributions to the development of XRF continue in abundance. Also as in previous years, we have chosen to highlight particular areas where developments in the technique have been, or are likely to be, most influential. These areas include total reflection XRF, portable and on-line instrumentation, developments in X-ray optics and synchrotron applications and, this year, contributions that cover the centenary of the discovery of X-rays. Within our experience and capabilities, this review covers the most important developments in the field since last year's review.

X-Ray Fluorescence

Instrumentation

10.1039/ja996110409r

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Citations (12)

A new technique for the deposition of standard solutions in total reflection X-ray fluorescence spectrometry (TXRF) using pico-droplets generated by inkjet printers and its applicability for aerosol analysis with SR-TXRF

Spectrochimica Acta Part B Atomic Spectroscopy (2006)

Ursula E. A. Fittschen Stephan Hauschild Martin A. Amberger Gerhard Lammel Christina Streli

X-Ray Fluorescence

Deposition

Fluorescence spectrometry

10.1016/j.sab.2006.09.009

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Citations (45)

Radiation imaging with optically read out GEM-based detectors

Journal of Instrumentation (2018)

F. Brunbauer M. Lupberger E. Oliveri F. Resnati L. Ropelewski

Modern imaging sensors allow for high granularity optical readout of radiation detectors such as MicroPattern Gaseous Detectors (MPGDs). Taking advantage of the high signal amplification factors achievable by MPGD technologies such as Gaseous Electron Multipliers (GEMs), highly sensitive detectors can be realised and employing gas mixtures with strong scintillation yield in the visible wavelength regime, optical readout of such detectors can provide high-resolution event representations. Applications from X-ray imaging to fluoroscopy and tomography profit from the good spatial resolution of optical readout and the possibility to obtain images without the need for extensive reconstruction. Sensitivity to low-energy X-rays and energy resolution permit energy resolved imaging and material distinction in X-ray fluorescence measurements. Additionally, the low material budget of gaseous detectors and the possibility to couple scintillation light to imaging sensors via fibres or mirrors makes optically read out GEMs an ideal candidate for beam monitoring detectors in high energy physics as well as radiotherapy. We present applications and achievements of optically read out GEM-based detectors including high spatial resolution imaging and X-ray fluorescence measurements as an alternative readout approach for MPGDs. A detector concept for low intensity applications such as X-ray crystallography, which maximises detection efficiency with a thick conversion region but mitigates parallax-induced broadening is presented and beam monitoring capabilities of optical readout are explored. Augmenting high resolution 2D projections of particle tracks obtained with optical readout with timing information from fast photon detectors or transparent anodes for charge readout, 3D reconstruction of particle trajectories can be performed and permits the realisation of optically read out time projection chambers. Combining readily available high performance imaging sensors with compatible scintillating gases and the strong signal amplification factors achieved by MPGDs makes optical readout an attractive alternative to the common concept of electronic readout of radiation detectors. Outstanding signal-to-noise ratios and robustness against electronic noise allow unprecedented imaging capabilities for various applications in fields ranging from high energy physics to medical instrumentation.

Gas electron multiplier

X-ray detector

Particle detector

10.1088/1748-0221/13/02/t02006

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Citations (18)

Recent Developments in Txrf of Light Elements

Advances in X-ray Analysis (1997)

Christina Streli V. Bauer P. Wobrauschek

10.1007/978-1-4615-5377-9_86

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Citations (3)

Measurement of the spectral distribution of a diffraction x‐ray tube with a solid‐state detector

X-Ray Spectrometry (1992)

R. Görgl P. Wobrauschek Peter Kregsamer Christina Streli

Abstract A knowledge of the spectral distribution method emitted by an x‐ray tube is important for all calculations in quantitative x‐ray fluorescence analysis. A simple way of directly measuring the primary spectrum of an x‐ray tube with a solid‐state detector is presented. For samples which meet thin‐film criteria sensitivity factors based on the measured primary spectrum were calculated and compared with experimental values.

X-ray tube

Spectral power distribution

10.1002/xrs.1300210110

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Citations (23)

Effect of iodine species on biofortification of iodine in cabbage plants cultivated in hydroponic cultures

Scientific Reports (2024)

Péter Dobosy Hoang Thi Phuong Nguyen Gyula Záray Christina Streli Dieter Ingerle

Abstract Iodine is an essential trace element in the human diet because it is involved in the synthesis of thyroid hormones. Iodine deficiency affects over 2.2 billion people worldwide, making it a significant challenge to find plant-based sources of iodine that meet the recommended daily intake of this trace element. In this study, cabbage plants were cultivated in a hydroponic system containing iodine at concentrations ranging from 0.01 to 1.0 mg/L in the form of potassium iodide or potassium iodate. During the experiments, plant physiological parameters, biomass production, and concentration changes of iodine and selected microelements in different plant parts were investigated. In addition, the oxidation state of the accumulated iodine in root samples was determined. Results showed that iodine addition had no effect on photosynthetic efficiency and chlorophyll content. Iodide treatment did not considerably stimulate biomass production but iodate treatment increased it at concentrations less than 0.5 mg/L. Increasing iodine concentrations in the nutrient solutions increased iodine content in all plant parts; however, the iodide treatment was 2–7 times more efficient than the iodate treatment. It was concluded, that iodide addition was more favourable on the target element accumulation, however, it should be highlighted that application of this chemical form in nutrient solution decreased the concetrations of selected micoelement concentration comparing with the control plants. It was established that iodate was reduced to iodide during its uptake in cabbage roots, which means that independently from the oxidation number of iodine (+ 5, − 1) applied in the nutrient solutions, the reduced form of target element was transported to the aerial and edible tissues.

Iodate

Potassium iodate

Trace element

Biofortification

10.1038/s41598-024-66575-z

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Citations (1)