We present a novel, highly efficient von Hamos spectrometer for X-ray emission spectroscopy (XES) in the laboratory using highly annealed pyrolitic graphite crystals as the dispersive element. The spectrometer covers an energy range from 2.5 keV to 15 keV giving access to chemical speciation and information about the electronic configuration of 3d transition metals by means of the Kβ multiplet. XES spectra of Ti compounds are presented to demonstrate the speciation capabilities of the instrument. A spectral resolving power of E/ΔE = 2000 at 8 keV was achieved. Typical acquisition times range from 10 min for bulk material to hours for thin samples below 1 μm.

Background Allergic reactions to tattoos are amongst the most common side effects occurring with this permanent deposition of pigments into the dermal skin layer. The characterization of such pigments and their distribution has been investigated in recent decades. The health impact of tattoo equipment on the extensive number of people with inked skin has been the focus of neither research nor medical diagnostics. Although tattoo needles contain high amounts of sensitizing elements like nickel (Ni) and chromium (Cr), their influence on metal deposition in skin has never been investigated. Results Here, we report the deposition of nano- and micrometer sized tattoo needle wear particles in human skin that translocate to lymph nodes. Usually tattoo needles contain nickel (6–8%) and chromium (15–20%) both of which prompt a high rate of sensitization in the general population. As verified in pig skin, wear significantly increased upon tattooing with the suspected abrasive titanium dioxide white when compared to carbon black pigment. Additionally, scanning electron microscopy of the tattoo needle revealed a high wear after tattooing with ink containing titanium dioxide. The investigation of a skin biopsy obtained from a nickel sensitized patient with type IV allergy toward a tattoo showed both wear particles and iron pigments contaminated with nickel. Conclusion Previously, the virtually inevitable nickel contamination of iron pigments was suspected to be responsible for nickel-driven tattoo allergies. The evidence from our study clearly points to an additional entry of nickel to both skin and lymph nodes originating from tattoo needle wear with an as yet to be assessed impact on tattoo allergy formation and systemic sensitization. Electronic supplementary material The online version of this article (10.1186/s12989-019-0317-1) contains supplementary material, which is available to authorized users.

a This paper presents recent achievements in laboratory based instrumentation for X-ray Absorption Fine Structure Spectroscopy (XAFS). The key component of the spectrometer is a HAPG mosaic crystal, which is employed in the von Hamos geometry. Due to the high efficiency of HAPG a low power micro focus X-ray tube can serve as an X-ray source. Besides a description of the spectrometer, the paper covers the treatment of the CCD images in detail. The latter is crucial in order to entirely exploit the potential of the HAPG (Highly Annealed Pyrolitic Graphite) spectrometer. One section is dedicated to applications. As a first kind of application, the concentrations of two different iron species in mixtures are determined. A second kind of typical usage of XAFS is the determination of bond lengths from the EXAFS. This XAFS application is demonstrated with metallic Ni as a reference material.

Highly annealed pyrolytic graphite (HAPG) is an advanced type of pyrolytic graphite that, as a mosaic crystal, combines high integral reflectivity with a very low mosaicity of typically less than 0.1°. When used as dispersive X‐ray optics, a high resolving power has been observed, rendering HAPG very suitable for applications in high‐resolution X‐ray spectroscopy, which conventionally relies on ideal crystals. For the design and modelling of HAPG crystals in applications requiring high spectral resolution, the diffraction properties must be known very accurately. To close this gap, a comprehensive characterization of HAPG crystals was performed that allows for modelling of the diffraction properties in different diffraction orders over a broad spectral range. The crystal properties under investigation are the mosaic spread, the peak reflectivity and the intrinsic reflection width. The investigations were carried out for different thickness crystal films, which were mounted adhesively on a substrate. It is shown that the diffraction properties are strongly correlated to the grade of adhesion, which depends crucially on the substrate material and its surface properties. The investigations were performed using monochromated tunable synchrotron radiation of high spectral purity with a high‐precision experimental setup and calibrated detection devices at the electron storage ring BESSY II.

This paper presents the development of a new reflection model for describing X-ray diffraction from mosaic crystals. In contrast to the well established diffraction model of Zachariasen [Zachariasen (1994), Theory of X-ray Diffraction in Crystals. Mineola: Dover Publications], it gives additional information on the spatial reflection behaviour and not just on the depthintegrated reflectivity of the crystal material. The new reflection model enables a concrete description of mosaic crystal performance in an arbitrary X-ray spectrometer configuration. Multiple reflections inside the crystal are described by splitting the calculation into a discrete number of reflections. Hence, the influence of each number of reflections is investigated, leading to a laterally resolved solution for the reflectivity. In addition, the model can use a mosaicity of arbitrary shape. This is important because the present work uses a Lorentzian-shaped mosaicity instead of a Gaussian one, which is usually the case in the most widely used simulation programs. A comparison between the new model and that of Zachariasen is performed, and it predicts a similar integrated reflectivity with a deviation lower than 0.7%. Further, a ray-tracing simulation with multiple reflections based on the new model is compared with a measurement, showing a deviation of lower than 5%.