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The combination of a pnCCD-based pixel detector with a poly-capillary X-ray optics was installed and examined at the Helmholtz-Zentrum Dresden-Rossendorf. The set-up is intended for Particle Induced X-ray Emission imaging to survey the trace elemental composition of flat/polished geological samples. In the standard configuration a straight X-ray optics (20 µm capillary diameter) is used to guide the emitted photons from the sample towards the detector with nearly 70000 pixels. Their dimensions of 48×48 µm2 are the main limitation of the lateral resolution. This limitation can be bypassed by applying a dedicated sub-pixel algorithm to recalculate the footprint of the photon’s electron cloud in the detector. The lateral resolution is then mainly determined by the capillary’s diameter. Nevertheless, images are still superimposed by the X-ray optics pattern. The optics’ capillaries are grouped in hexagonal bundles resulting in a reduced transmission of X-rays in the boundary regions. This influence can be largely suppressed by combining a series of short measurements at slightly shifted positions using a precision stage and correcting the image-data for this shifting. The use of a sub-pixel grid for the image reconstruction allows a further increase of the spatial resolution. This approach of multi-frame super-resolution in combination with the sub-pixel correction algorithm is presented and illustrated with experimental data. Additionally, a flat-field correction is shown to remove the remaining imaging inhomogeneity caused by non-uniform X-ray transmission. The described techniques can be used for all X-ray spectrometry methods using an X-ray camera to obtain high quality elemental images.

In a fast growing world with increasing demand on resources like high-tech metals as In, Ga, Ge, or rare earth elements (REE), mineralogists and economic geologists need faster and automated analytical tools to explore mineral deposits, make them accessible and define necessary initial data for all subsequent processing steps. Next to the necessary knowledge in which phases the elements of interest, ecotoxical as well as deleterious elements are concentrated, it is important to determine structural parameters like grain sizes and possible intergrowths relations of these minerals. These are typical geometallurgical analytical tasks, which are so far routinely performed by electron beam based methods of automated mineralogy, like MLA (mineral liberation analysis) or QEMSCAN, with their advantages and disadvantages. The methodological problems of these type of methods are, for example, the necessary measurement time, insufficient limits of detection (no trace element detection) and high background (electron Bremsstrahlung). Some of these hurdles can be overcome by using alternative excitation radiation, like ions, known as particle-induced X-ray emission (PIXE) or X-rays, known as X-ray fluorescence (XRF). Combining these with a full-field detection system, such as the so-called SLcam®[1], allows the determination of trace element distributions in reasonable time over a large field of view. The SLcam® consists of a 12 x 12 mm², X-ray sensitive pnCCD chip with 69696 pixels. A high read-out speed of up to 1000 Hz, allows the acquisition of complete X-ray spectra (2-20 keV) on each pixel simultaneously, with an energy resolution of around 160 eV (@ Mn-K even for high photon fluxes. A poly-capillary lens is used to guide the X-rays from their point of origin on the sample to the corresponding pixel on the detector-chip. Usage of a straight 1:1 lens results in a lateral resolution better than 100 µm. The MEGA spectrometer is equipped with a laboratory-scale X-ray tube. XRF is used for the determination of major and trace element data. It’s “small”, table-top like size would in principle allow to use the set-up directly at the mining site. The so called High-Speed PIXE[2] uses a broad proton beam to excite the fluorescence radiation. Samples with a total weight of up to 10 kg and a maximum size 25 x 25 x 2.5 cm³ can be mounted in a dedicated vacuum sample chamber. The instrument is installed at the Ion Beam Center at the Helmholtz-Zentrum Dresden-Rossendorf. The advantages and disadvantages of both instruments will be presented, as well as first results of combined qualitative studies of the distribution of trace elements in representative samples to demonstrate the importance of these innovative concepts for geometallurgical research. [1] Scharf, O., et al. (2011). Compact pnCCD-Based X-ray Camera with High Spatial and Energy Resolution: A Color X-ray Camera. Analytical Chemistry, 83(7), 2532–2538. [2] Hanf, D., et al. (2016). A new particle-induced X-ray emission set-up for laterally resolved analysis over wide areas. Nuclear Instruments and Methods in Physics Research B, 377, 7-24.

The nuclear microprobe that was installed in 1994 at the Ion Beam Center of the Helmholtz-Zentrum Dresden-Rossendorf [1], has been in operation up to 2014 with only minor changes. After 20 years it became necessary to make an upgrade to replace old components and bring the setup up to current standards of technology and good working practice. The major drawback of the old system was the optical microscope, especially the poor resolution and low contrast and brightness. However, a good optical image is essential to localise the areas of interest on, for example, large geological samples. Since the focused beam of MeV ions and the corresponding detectors is the principal investigative tool, any other equipment such as an optical microscope has to be designed around this device. A new microscope has been installed for which the first light-collecting lens is mounted directly into the chamber at only a few centimetres from the sample. The light is then guided over large mirrors and focussed on a CCD camera outside the sample chamber. The illuminating light is fed in through the lenses instead of using an external light source as in the old system. In addition, there is also a light source opposite to the microscope, allowing transmission illumination including through a polarising filter making polarised imaging possible. Other improvements concern the control of the scanning system as well as the control and monitoring of all relevant experimental parameters. The control of the scan magnets is done by custom-designed hardware to guarantee real-time execution of the scanning without the need for a computer running a real-time operating system. Controlling and monitoring of the experiment are implemented to facilitate easy and secure operation of the microprobe by the user with special emphasis on operation by un-experienced users, since the device is part of the user facility IBC. All standard IBA techniques like PIXE, PIGE, RBS, NRA, ERDA and STIM are available and, in addition, a Channeltron detector has been installed to detect secondary electrons that allow quick imaging of the measurement area. Technical details and first test measurements with the new system are presented. [1] F. Herrmann, D. Grambole, Nucl. Instr. Meth. B 104 (1995) 26.

The nuclear microprobe that was in operation until 2104 at the Ion Beam Center of the Helmholtz-Zentrum Dresden-Rossendorf was installed in 1994 [1]. It has been in operation since then with only minor changes. This necessitated an upgrade to bring the setup up to current standards of technology and good working practice. This study presents the details of the upgrade and modernization process we have undertaken. The major drawbacks of the old system were the poor resolution and low contrast and brightness of the optical microscope. However, a good optical image is essential to localise the areas of interest on, for example, large geological samples. On the other hand, the main investigative tool is the focused beam of high-energy ions and the corresponding detectors. Any other system such as an optical microscope has to be designed around this equipment. A new custom-designed microscope has been installed for which the first light-collecting lens is mounted in the sample chamber at only a few centimetres from the sample. The light is then guided over large mirrors and focussed on a CCD camera outside the sample chamber. Also the illumination is fed in through the lenses instead of using a separate light source as in the old system. The lens system can also serve as a basis for a possible ionoluminescence detector. Other improvements concern the beam deflection system, the control of the scanning system and the control and monitoring of all relevant parameters for the experiment. The control of the scanning system is done by custom-designed hardware to guarantee the real-time execution of the scanning without the need for a computer with a real-time operating system. This makes it possible to use a standard Windows based computer with commercial software for the data acquisition. A new channeltron has also been installed to detect secondary electrons that can be used to obtain a quick overview of an measurement area. Technical details and first test measurements with the new system are presented. [1] F. Herrmann, D. Grambole, Nucl. Instr. Meth. B 104 (1995) 26.

The combination of a pnCCD-based detector with a poly-capillary X-ray optics was installed and examined at HZDR [1]. The set-up is intended for PIXE imaging with protons (2-4 MeV) to survey large, polished geological samples with respect to their trace elemental composition. The X-ray optics is used to guide the emitted photons towards the pnCCD-chip divided into nearly 70000 pixels with dimensions of 48 × 48 µm². By applying a dedicated sub-pixel algorithm to recalculate the footprint of the photon’s electron cloud in the chip [2], this limitation can be bypassed and the resolution is then mainly determined by the capillary’s diameter of 20 µm. Nevertheless, all images gathered with this kind of set-up from are superimposed by patterns of the X-ray optics. The optics’ capillaries are grouped in hexagonal bundles during the fabrication process and these bundles are grouped together again. This process results in a reduced efficiency in the regions where the bundles are joined making the hexagonal pattern visible. This influence can be removed by the technique of multi-frame super-resolution combining several short measurements with slightly shifted positions. The optics pattern is averaged out and in addition the shifting allows further increase of the lateral resolution. The total measurement time can be kept similar by dividing the single measurement time by the number of “shots” without reducing the sampling size. This approach of multi-frame super-resolution in combination with a sub-pixel correction algorithm will be illustrated and shown on experimental data. Additionally, a flat-field correction attempt is shown to remove general imaging inhomogeneity. Descriptive image-sets will be presented to demonstrate the potential of such techniques for full-field PIXE imaging [3]. [1] D. Hanf, J. Buchriegler, A. D. Renno, S. Merchel, F. Munnik, R. Ziegenrücker, O. Scharf, S. H. Nowak, J. von Borany, NIM B 377, pp. 17-24 (2016). [2] S. H. Nowak, A. Bjeoumikhov, J. von Borany, J. Buchriegler, F. Munnik, M. Petric, A. D. Renno, M. Radtke, U. Reinholz, O. Scharf, L. Strüder, R. Wedell, R. Ziegenrücker, X-ray Spectrometry 44 (3), pp. 135-140 (2015). [3] J. Buchriegler, N. Klingner, D. Hanf, F. Munnik, S. H. Nowak, O. Scharf, R. Ziegenrücker, A. D. Renno, J. von Borany, submitted to Journal of Analytical Atomic Spectrometry (2017) This work has been supported by BMBF (INTRA r3 033R070) and by Marie Curie Actions - Initial Training Network (ITN) as an Integrating Activity Supporting Postgraduate Research with Internships in Industry and Training Excellence (SPRITE) under EC contract no. 317169.

In recent years significant efforts have been made to combine Particle Induced X-ray Emission (PIXE) techniques with the advantages of the Color X-ray Camera [1] to produce full-field PIXE images of trace element distributions in geological samples [2]. Decisive progress was made by the implementation of several image enhancement techniques [3, 4]. The ultimate objective is the installation of an analytical instrument running in routine operation. The major advantage of this new approach is the ability to gather elemental distribution maps over a large field of view (some cm²) with reasonable spatial resolution (< 100 µm) in real-time. Setting a matrix-dependent threshold value for a certain trace element concentration will allow us to reduce the measurement time compared to beam scanning based methods. This is an enormous advantage for resource technological application. The present status of the installation at HZDR Ion Beam Center does not enable us to obtain quantitative information about trace element concentration in the single pixels of the resulting elemental distribution maps. The information content of qualitative and quantitative distribution maps is different. But it is a myth that only quantitative information is suitable of gathering information about rocks, ores and minerals. Using selected examples from petrology, economic geology and resource technology we will demonstrate the different types of qualitative information and its interpretation. [1] O. Scharf, et al., Analytical Chemistry 83 (7) (2011) 2532–2538. [2] D. Hanf, et al., NIM B 377, pp. 17-24 (2016). [3] J. Buchriegler, et al. submitted (2017). [4] S. Nowak, et al., arXiv:1705.08939, (2017). This work has been supported by BMBF (INTRA r3 033R070) and by the EU project SPRITE (GA-No. 317 169).

Metal induced crystallization (MIC) is a promising technique for low-temperature thin film transistor fabrication and graphene synthesis. In MIC, a transition metal catalyzes the crystallization of the amorphous phase of a group IV element by bond screening near the interface and facilitation of nucleation. So far, in situ studies have been performed using X-ray diffraction, which is sensitive to the degree of crystallinity. In situ Rutherford backscattering spectrometry has the advantage of elemental depth resolution and time resolved tracking of diffusion and layer exchange processes. Graphene formation through MIC has been demonstrated with an a-C/Ni layer stack [1]. As a model system for MIC, the Si/Ag bilayer system is studied here. The Si/Ag layer stacks are annealed at temperatures of 380 to 700 °C. Depth profiles of the elements are investigated by in situ RBS. Their analysis reveals the diffusion kinetics of the elements. The changes in the phase structure are explored by in situ Raman spectroscopy. Both the quick initial nucleation and ensuing growth processes are investigated. [1] Weatherup et al., Nano Letters 13, pp. 4624 (2013)

Analytical codes dedicated to the analysis of Ion Beam Analysis data rely on the accuracy of both the calculations and of basic data such as scattering cross sections and stopping powers. So far, the effect of the beam charge state of the incoming beam has been disregard by general purpose analytical codes such as NDF. In fact, the codes implicitly assume that the beam is always in the equilibrium charge state, by using tabulated stopping power values e.g. from SRIM, which are in principle valid for the equilibrium charge state. The dependence of the stopping power with the charge state is ignored. This assumption is reasonable in most cases, but for high resolution studies the actual change of the charge state from the beam charge state towards equilibrium as it enters and traverses the sample must be taken into account, as it influences the shape of the observed data. In this work, we present an analytical calculation, implemented in NDF, that takes this effect into account. For elastic recoil detection analysis (ERDA), the changing charge state of the recoils can also be taken into account. We apply the calculation to the analysis of experimental high depth resolution ERDA data for various oxide layers collected using a magnetic spectrometer.

A new PIXE (particle-induced X-ray emission) beamline equipped with a full-field energy-dispersive X-ray camera [1,2] has been recently put into operation at HZDR. The so-called High-Speed PIXE is a combination of a 264 x 264 pixel-detector with polycapillary optics guiding the proton-induced X-ray fluorescence radiation towards a pnCCD-chip with an energy resolution of 156 eV (@Mn-Kα). It allows a fast detection of elements over a field of 12 x 12 mm² simultaneously with a lateral resolution better than 100 µm, even at the trace level (

The so-called “High-Speed PIXE” is a novel combination of the SLcam® [1,2] and PIXE. The pixel-detector comprising 264 x 264 pixels in combination with a polycapillary 1:1 X-ray optics allows a fast detection of elements over a field of 12 x 12 mm² simultaneously with a lateral resolution below 100 μm. In order to approach the final goal of quantitative analysis of geological samples, a homogeneous proton irradiation is essential. This can be realised by scanning a finefocused beam electrostatically across the area of interest which also minimises the required over-scan area. However, the corresponding high proton density favours pile-up effects. In contrast to a classical micro-beam PIXE set-up, charge is collected in all pixels simultaneously for 1 ms. To enable trace element analysis, pile-up effects have to be suppressed calling for lower current densities. [1] O. Scharf et al., Anal. Chem., Vol. 83, pp. 2532-2538 (2011). [2] I. Ordavo et al., NIM A, Vol. 654, pp. 250-257 (2011).

Metal induced crystallization (MIC) is a promising technique for thin film transistor fabrication and graphene synthesis. In MIC, a transition metal catalyzes the crystallization of the amorphous phase of a group IV element by bond screening near the interface and facilitation of nucleation. So far, in situ studies have been performed using X-ray diffraction which is sensitive to the degree of crystallinity. However this technique lacks depth resolution and is therefore unable to track diffusion and layer exchange. Here, the Si/Ag and C/Ni bilayer systems are studied. The samples are annealed at temperatures of up to 750 °C. Simultaneously, depth profiles of the elements are investigated by in situ Rutherford backscattering spectroscopy revealing the diffusion kinetics. The changes in the phase structure are explored by in situ Raman spectroscopy. Both the quick initial nucleation and ensuing growth processes are investigated. Scanning electron microscopy provides insight to the surface morphology.

Contrary to popular opinion we have to accept that not every significant enrichment of rare-earth-elements (REE) in the earth’s crust is economically and ecologically exploitable. Deposits of heavy rare earth elements are of particular interest. A further critical point is the knowledge in which phases the elements of interest, ecotoxical as well as deleterious elements are concentrated. This information must be complemented by the determination of grain size and possible intergrowths of mineral phases. These are typical geometallurgical analytical tasks routinely performed by methods of automated mineralogy, like MLA or QEMSCAN. The newly established High-Speed PIXE (Particle Induced X-ray Emission) set-up at HZDR combines the capabilities of electron beam based devices with fast determination of trace elements. On the basis of qualitative studies of the distribution of REE in REE-mineralizations as well as in different REE-minerals like bastnaesite, monazite and xenotim we will prove the importance of this innovative concept for geometallurgical research.

Metal induced crystallization (MIC) is a promising technique for low temperature thin film transistor fabrication and graphene synthesis. In MIC, a transition metal acts as seed for the crystallization of an amorphous group IV element. Bond screening near the interface and facilitation of nucleation are recently discussed as mechanisms for MIC. So far, in situ studies have been performed using X-ray diffraction, which is sensitive to the degree of crystallinity but lacks depth resolution. A better insight into the MIC mechanisms requires depth resolved in situ studies in order to determine the concentration profiles of the diffusing components. Here, the Si/Ag and C/Ni bilayer systems are studied. They are annealed at temperatures of up to 750 °C. Simultaneously, the layer composition and the compositional profiles are investigated with in situ Rutherford backscattering spectroscopy revealing the diffusion kinetics of the components. Both, the quick initial nucleation and the ensuing growth processes are investigated. Further characterization is performed employing in vacuo Raman spectroscopy revealing the phase structure of the resulting films and scanning electron microscopy to investigate the surface structure.

Das Helmholtz-Institut Freiberg für Ressourcentechnologie entwickelt innovative Analysemethoden, um Technologien zur Erkundung, Gewinnung, Nutzung und Recycling von Rohstoffen entlang der Wertschöpfungskette zu bewerten und zu verbessern. Eines dieser neuen Verfahren ist die unikale High-Speed PIXE, eine schnelle ortsaufgelöste teilchen-induzierte Röntgenemission (PIXE = Particle-Induced X-ray Emission). Via High-Speed PIXE wird die chemische Zusammensetzung großflächiger Proben in kurzer Zeit (min-h) bestimmt. Die elementspezifische Röntgenstrahlung wird mit 3 MeV Protonen aus einem Tandembeschleuniger [1] angeregt. Der ca. 3 mm große Strahl wird mittels eines elektrostatischen Scanningsystems aufgeweitet und regt simultan alle Atome über einer Probenfläche von bis zu 12 x 12 mm² an. Für die ortsaufgelöste Detektion wird eine sog. Röntgenfarbkamera SLcam® [2] verwendet, bestehend aus einer speziellen Röntgenkapillaroptik in Verbindung mit einer pnCCD. Der Detektorchip dieser Kamera ist aus 69696 48x48 µm² großen Pixeln aufgebaut, die alle ein energieaufgelöstes, elementspezifisches und quantifizierbares Röntgenspektrum messen. Es sind somit Elementverteilungsbilder mit einer lateralen Auflösung von 50 µm (in Zukunft mit 6:1-Optik ~10 µm) möglich. Derzeit können alle Elemente von Magnesium bis Uran und zukünftig ab Bor mit Nachweisgrenzen bis in den µg/g-Bereich detektiert werden. Ref.: [1] Akhmadaliev et al., NIMB 294 (2013) 5. [2] Scharf et al., Anal. Chem. 83 (2011) 2532.

The so-called “High-Speed PIXE” is a novel combination of the SLcam® [1,2] and proton-induced X-ray emission (PIXE). The fluorescence radiation is excited by 3-4 MeV protons provided by the 6 MV tandem accelerator at HZDR. The pixel-detector comprising 264 x 264 pixels in combination with a polycapillary X-ray optics allows a fast detection of laterally resolved elemental maps over a detection area of 12 x 12 mm² simultaneously for all pixels. Based on the pixel size of 48 x 48 μm² and considering the Nyquist-Shannon sampling theorem a lateral resolution better than 100 μm should be achievable. By measuring well-known structures of copper and chromium with appropriate dimensions, this assumption could be verified. The system is intended for the detection of trace elements in geological samples by using a pnCCD-chip with an energy resolution better than 160 eV (@Mn Kα) for each pixel. The distribution of known trace element concentrations (

Moderne Werkstoffe sind bei vielen Anwendungen extremenUmgebungsbedingungen ausgesetzt. Dazu zählen hohe und tiefe Temperaturen bzw. große Temperaturschwankungen, die teilweise in Verbindung mit korrosiven oder reaktiven Atmosphären oder hohen mechanischen Belastungen auftreten. Sie stellen hohe Anforderungen an die Beständigkeit und Stabilität der verwendeten Werkstoffe. Als Beispiele seien solarselektive Absorber, Komponenten des Antriebsstranges von Verbrennungsmotoren und Rotoren von Turboladern und Turbinen genannt. Die Gewährleistung der Werkstofffunktionalität über die gesamte Lebensdauer erfordert neue Konzepte der Analyse und Prüfung. Dazu wurde am 6MV Ionenbeschleuniger des HZDR mit Fördermitteln des Impuls- und Vernetzungsfonds des Präsidenten der HGF sowie des KFSI ein Cluster-Tool zur in situ Modifizierung und Analyse von Werkstoffen bei Temperaturen von bis zu 1000°C, unter korrosiven Atmosphären und mechanischem Verschleiß aufgebaut. Kernbestandteil des Cluster-Tools ist eine zentrale Hochvakuum (HV)-Probenaufnahme- und Transferkammer. Diese ist mit weiteren HV-Kammern verbunden, in denen die sequentielle Probensynthese und -modifizierung, die Element- und Strukturanalytik und die optische Charakterisierung erfolgt, ohne das Vakuum zu brechen und die Werkstoffe undefinierten Umgebungsbedingungen auszusetzen. In allen Kammern besteht die Möglichkeit, in situ Heizexperimente bei Temperaturen von bis zu 1000°C durchzuführen. Die mit dem 6MV Tandem-Ionenbeschleuniger verbundene Kammer zur Ionenstrahlanalytik ermöglicht die Untersuchung der Elementzusammensetzung durch Rutherford Rückstreuung und Nuklearer Reaktionsanalyse. Die Schichtzusammensetzung kann bis in eine Tiefe von ca. 1μm auf bis zu 10 nm genau bestimmt werden. Bei Hochtemperaturuntersuchungen reduziert sich die Tiefenauflösung auf etwa 25 nm. Zur strukturellen Charakterisierung der Proben dient ein fasergekoppeltes Ramanspektrometer an der Analysenkammer des Cluster-Tools, dessen Probenkopf über eine Kamera auch die visuelle Beurteilung der Proben ermöglicht. Die Untersuchung der optischen Eigenschaften und deren Abhängigkeit von Temperatur und Atmosphäre erfolgt durch spektroskopische Ellipsometrie in einer Umweltkammer, in der korrosive Umgebungen simuliert werden können. Für 2015 ist die Installation eines in situ Tribometers in Vorbereitung, mit dem das Reib- und Verschleißverhalten von Werkstoffen unter definierten Atmosphären untersucht werden kann. Zusammengefasst entsteht mit dem Cluster-Tool am 6 MV Ionenbeschleuniger des HZDR ein Messplatz zur umfassenden in situ Modifizierung und Analyse von Werkstoffen, mit Hilfe dessen komplexe Probenbehandlungsprotokolle unter extremen Umgebungsbedingungen bearbeitet werden können.

Methods of automated mineralogy form the analytical backbone of geometallurgy. Most of them exploit the combined imaging and analytical capabilities of optical and scanning electron microscopes. Typical results are „phase maps“ either derived from the distribution of major elements or determined directly. The effective application of such methods for strategic metals which are won as by-products from other metal ores or secondary raw materials is handicapped by the restricted possibilities to determine the spatial distribution of such trace elements like In, Ga, Ge or the rare earth elements (REE). The recently commissioned High-Speed PIXE (Particle Induced X-Ray Emission) setup at the Helmholtz-Institute Freiberg for Resource Technologies will overcome these limitations by using the advantages of PIXE over traditional electron beam based methods like the better peak-background ratio. We use the SLcam® Colour X-ray Camera - a novel pnCCD pixel detector (264×264=69696 pixel) combined with a polycapillary X-ray optics (Scharf et al., 2011) as detector for element specific X-ray radiation. This design allows us the simultaneous determination of trace element distributions on a 12 × 12 mm2 area with a lateral resolution better than 100 μm. First results of geometallurgical applications of this method are presented.

Methods of automated mineralogy form the analytical backbone of geometallurgy. Most of them exploit the combined imaging and analytical capabilities of optical and scanning electron microscopes. Typical results are „phase maps“ either derived from the distribution of major elements or determined directly. The effective application of such methods for strategic metals which are won as by-products from other metal ores is handicapped by the restricted possibilities to determine the spatial distribution of such trace elements like In, Ga, Ge or the rare earth elements (REE). The recently comissioned High-Speed PIXE (Particle Induced X-Ray Emission) setup at the Helmholtz-Institute Freiberg for Resource Technologies will overcome these limitations. We use the SLcam® X-ray Color Camera - a novel pnCCD Pixel detector (264 x 264 = 69696 Pixel) combined with a polycapillary X-ray optic (Scharf et al., 2011) as the detector for the element specific X-ray radiation. This design allows us the simultaneous determination of the trace element distribution on a 12 * 12 mm2 area with a lateral resolution of about 50 μm. First results of geometallurgical applications of this method are presented.

Das Helmholtz-Institut Freiberg für Ressourcentechnolgie (HIF @ HZDR) entwickelt unter dem Schlagwort „Ressourcenanalytik“ neue Analysemethoden, um Technologien zur Erkundung, Gewinnung, Nutzung und dem Recycling von Rohstoffen entlang der Wertschöpfungskette zu bewerten und zu verbessern. Eines dieser neuen Verfahren ist eine weltweit unikale High-Speed PIXE, das ist die schnelle ortsaufgelöste Teilchen-induzierte Röntgenemissionspektrometrie (PIXE = Particle-Induced X-ray Emission). Mittels High-Speed PIXE wird die elementare Zusammensetzung großformatiger Erzproben in kurzer Zeit (min-h) quantitativ bestimmt. Neben den für die Ressourcentechnologie wichtigen geologischen und aufbereitungstechnischen Proben, sind Materialanalysen möglich und bei entsprechender Probenvorbereitung, da die Messung im Vakuum erfolgt, auch biologische oder medizinische Proben analysierbar. Im Gegensatz zur Elektronen-induzierten EDX (EDX = Energy dispersive X-ray spectrometry) wird die spezifische Röntgenstrahlung bei der PIXE mit Protonen angeregt. Ein 6 MV Tandem-Teilchenbeschleuniger[1] erzeugt Protonen mit einer Energie von 4,2 MeV. Der 2 bis 3 mm große Teilchenstrahl wird anschließend aufgeweitet und regt simultan alle Atome über einer Probenfläche von 12x12 mm² an. Die dabei entstehende Röntgenstrahlung ist für die enthaltenen Elemente charakteristisch und kann quantitativ ausgewertet werden. Für die ortsaufgelöste Detektion wird eine sogenannte Röntgenfarbkamera SLcam®[2] verwendet, bestehend aus einer speziellen Röntgenkapillaroptik, die am IFG (IFG = Institut for Scientific Instruments) in Berlin entwickelt wurde in Verbindung mit einer pnCCD der Firma PNSensor. Der Detektorchip dieser Kamera ist aus 69696 48x48 µm² großen Pixeln aufgebaut, die alle ein komplettes energieaufgelöstes Röntgenspektrum messen können. In der Abbildung sind mit der High-Speed PIXE gemessene Element-verteilungsbilder mit einer lateralen Ortsauflösung von 50 µm (bis ~10 µm möglich) dargestellt; links kumulativ alle Röntgenphotonen und rechts nur die K-alpha- und K-beta-Linien von As. Im Moment können alle Elemente ab Mg und zukünftig sogar ab B mit elementspezifischen Nachweisgrenzen bis in den µg/g-Bereich detektiert werden. Referenzen: [1] S. Akhmadaliev et al., Nucl. Instr. Meth. B 294 2013, doi:10.1016/j.nimb.2012.01.053 [2] O. Scharf et al., Analyt. Chem. 83 2011, doi: 10.1021/ac102811p

A new 6 MV electrostatic tandem accelerator has been put into operation at Helmholtz-Zentrum Dresden-Rossendorf (HZDR). It will be used for ion beam analysis as well as for material modification via high-energy ion implantation. The system is also equipped for accelerator mass spectrometry and opens a new research field at HZDR and the Helmholtz Association. The research activity at the DREsden Accelerator Mass Spectrometry facility (DREAMS) based on a 6 MV Tandetron is primarily dedicated to the long-lived radioisotopes of 10Be, 26Al, 36Cl, 41Ca, and 129I. DREAMS background levels have been found of 4.5x10-16 for 10Be/9Be, 8x10-16 for 26Al/27Al, 3x10-15 for 36Cl/35Cl and 8x10-15 for 41Ca/40Ca, respectively. The observed background of 2x10-13 for 129I/127I originates from intrinsic 129I from AgI produced from commercial KI. The introduction of quality assurance approaches for AMS, such as the use of traceable calibration materials and taking part in interlaboratory comparisons, guarantees high accuracy data for future DREAMS users. During first experiments an energy calibration of the accelerator has been carried out using the nuclear reaction 1H(15N,γα)12C yielding an energy correction factor of 1.019.

Summary: A new approach using poly-capillaries has been used for laterally resolved PIXE. Promising for large area surveys. The experimental setup is ready and works. Outlook: Start of a Ph.D. student in the framework of the Marie-Cure project SPRITE. Some technical extensions have still to be installed. Development data-reduction protocols and image reconstruction. Development of integrated control and analysis software.

With decreasing layer thicknesses e.g. in semi-conductor devices, there is a strong need for increasing depth resolution in analytical methods used for the determination of elemental depth profiles. Standard RBS using Si detectors has a depth resolution of about 5 – 15 nm mainly depending on incidence angle and energy resolution. The traditional and high-tech solution is to use a magnetic spectrometer or a time-of-flight system to improve the energy resolution of the detector and thus the depth resolution. At HZDR, a Browne-Buechner type magnetic spectrometer is available for high depth resolution measu¬rements with sub-nm depth resolution in a near-surface region  5 nm. However, such a system is expensive and requires complicated operation. In addi¬tion, the small energy window of the magnetic spectrometer limits the measurement to one element and about 10 nm depth range. Currently we are implementing a low-tech detection system that uses improvements in amplifiers and cooling to improve the energy resolution of standard semiconductor detectors to sub-10 keV values. The capabilities of such a system are described and compared to the magnetic spectrometer.

A new 6 MV electrostatic tandem accelerator has been put into operation at Helmholtz-Zentrum Dresden-Rossendorf (HZDR). It will be used for ion beam analysis as well as for material modification via high-energy ion implantation. The system is also equipped for accelerator mass spectrometry and opens a new research field at HZDR and the Helmholtz Association. The research activity at the DREsden Accelerator Mass Spectrometry facility (DREAMS) based on a 6 MV Tandetron is primarily dedicated to the long-lived radioisotopes of 10Be, 26Al, 36Cl, 41Ca, and 129I. DREAMS background levels have been found of 4.5·10-16 for 10Be/9Be, 8·10-16 for 26Al/27Al, 3·10-15 for 36Cl/35Cl and 8·10-15 for 41Ca/40Ca, respectively. The observed background of 2·10-13 for 129I/127I originates from intrinsic 129I from AgI produced from commercial KI (MERCK). During first experiments at the accelerator an energy calibration of the machine has been carried out. For this purpose the 1H(15N,γ α)12C nuclear reaction has been used. The charge states of the 15N ion of 1+, 2+ and 3+ corresponding to different terminal voltages of the accelerator have been chosen to obtain an absolute energy calibration.

The 6 MV tandem type accelerator replaces the old 5 MV machine in the beginning of 2011. Besides ion beam analysis (IBA) and material modification via high-energy ion implantation, the system is equipped for accelerator mass spectrometry (AMS). The first interest is in the radioisotopes 10Be, 26Al, 36Cl, 41Ca, and 129I [1]. An energy calibration of the machine and a test of ion beam energy stability have been carried out as a first experiment using the 1H(15N,alpha gamma)12C nuclear reaction with a sharp resonance at anenergy of 6385 keV. The total energy resolution for the system is about 12 keV. First tests of the Dresden AMS system (DREAMS) [2] have been performed and demonstrated background levels of 2E-16 for 10Be/9Be, 7E-16 for 26Al/27Al and 8E-15 for 41Ca/40Ca, respectively. The background of 2E-13 for 129I/127I originates from intrinsic 129I (MERCK KI), whereas the reasons for high 36Cl/35Cl background of 3E-15 are under discussion. References: [1] Sh. Akhmadaliev et al., MS6.2, DPG Frühjahrstagung der Sektion AMOP, Hannover 2010. [2] www.dresden-ams.de

Demands on modern silicon detector technology and the detector development for improving analysis in the frame of the EU-Project SPIRIT will be described. For high energy resolution RBS and ERDA experiments large area silicon strip detector with increased sensitivity and energy resolution down to 10 keV FWHM (He+ at max. 2MeV) are required. By applying such strip detectors with certain position resolution kinematic correction procedures will be possible.

Die Bremsung von Schwerionen mit MeV-Energien bei Bewegung in Materie hängt von deren Energie und Ladungszustand ab. Nach einer durchlaufenen Strecke von ca. 50 nm stellt sich eine energieabhängige Gleichgewichtsverteilung der Ladungszustände ein. Auf dieser Verteilung der Ladungszustände beruhen die tabellierten Werte für das mittlere Bremsvermögen [1], die bei den ionenstrahlanalytischen Verfahren der Rutherford-Rückstreu-Spektrometrie (Rutherford Backs-cattering Spectrometry - RBS) und der elastischen Rückstreuanalyse (Elastic Recoil Detection Analysis - ERDA) zur Berechnung der Streutiefe eingesetzt werden. Die Verteilung der Ladungszustände der Ionen nach atomaren Stößen unterscheidet sich von der Gleichgewichtsverteilung. Beim Einsatz höchstauflösender magnetischer oder elektrostati-scher Spektrometer zur Charakterisierung ultradünner Schichten betragen die Weglängen der Ionen in der Probe nur wenige Nanometer. Es wird dabei kein Ladungsgleichgewicht erreicht und zur Auswertung der Messdaten müssen die unterschiedlichen Bremsvermögen und die Um-ladungsquerschnitte der einzelnen Ladungszustände berücksichtigt werden. Experimentelle Daten für den für die Ionenstrahlanalyse interessanten Energiebereich von we-niger als 30 MeV liegen nach unserem Wissen nicht vor. Aus diesem Grunde wurden Brems-vermögen und Umladungsquerschnitte leichter Schwerionen (Bor, Kohlenstoff, Stickstoff, Sau-erstoff und Fluor) an ultradünnen DLC-Kohlenstofffolien (Diamond Like Carbon) im Energiebe-reich von 3-14 MeV für die unterschiedlichen Ladungszustände untersucht. Dazu wurde eine experimentelle Anordnung mit elektrostatischem Analysator, ähnlich der in [2] beschriebenen, verwendet, bei der zwei DLC-Folien hintereinander angeordnet sind. Die erste Folie mit einer Massenflächendichte von 2,0 bzw. 2,7 µg/cm² dient dabei als Stripperfolie. Die Ionen unter-schiedlicher Ladung haben nach dem Passieren dieser Folie eine identische Energieverteilung. In kurzem Abstand folgt eine ultradünne Targetfolie mit einer Massenflächendichte zwischen 0,5 und 0,9 µg/cm². Dies entspricht einer Dicke von ca. 2,5 bis 4,5 nm. Diese Folie ist ausreichend dünn, um Vielfachumladungen zu vermeiden. Zur Bestimmung der Umladungsquerschnitte wur-de, analog der von A. Blažević et al. beschriebenen Methode [3], das Potential der Stripperfolie um 30 kV gegenüber der Targetfolie angehoben. Die hier gewonnen Ergebnisse fließen in die Verbesserung der Präzision und Richtigkeit der mit hochauflösender RBS und ERDA produzierten Daten ein. Referenzen [1] J.F. Ziegler, Nucl. Instr. and Meth. B 219-220 (2004) 1027. URL: http://www.SRIM.org. [2] W. Jiang et al, Phys. Rev. B 59 (1999) 226. [3] A. Blažević et al, Phys. Rev. A 61 (2000) 032901.

The aim of the modified magnetic spectrometer “Little John” [1] is to measure concentration profiles of light elements in thin layers with sub-nanometer depth resolution by Elastic Recoil Detection Analysis (ERDA). For these measurements heavy ions from the Rossendorf 5-MV-Tandem accelerator are directed to the sample. The ejected recoil atoms are detected and energy analysed under forward angles. The depth resolution depends directly on the energy resolution of the spectrometer. High energy resolutions can be obtained using magnetic particle spectrometers, where the energy measurement is transformed into a position measurement at the focal plane. The depth scale is provided by the stopping power of energetic heavy ions moving in matter, the available data of which assume a dynamic charge state equilibrium due to electron loss and capture along the ion trajectory. In the case of ultrathin layers the path length of the particles are too short to achieve this equilibrium. Since magnetic spectrometers separate particles with identical energy but different charge states it is necessary to consider charge state dependent stopping cross sections for quantitative data analysis. Here only very few data are available in the literature. In this work we introduce an experimental setup at “Little John” for charge state distribution measurements of light heavy ions and present first results. References: [1] H.J. Gils, J. Buschmann, S. Zagromski, J. Krisch and H. Rebel, Nucl. Instr. and Meth. A276 (1989), p. 151. .