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Subject: Spectrum analysis × WGL Institute: IPHT ×

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    Raman imaging to study structural and chemical features of the dentin enamel junction
    (London [u.a.] : Institute of Physics, 2015) Alebrahim, M.A.; Krafft, C.; Popp, J.; El-Khateeb, Mohammad Y.
    The structure and chemical features of the human dentin enamel junction (DEJ) were characterized using Raman spectroscopic imaging. Slices were prepared from 10 German, and 10 Turkish teeth. Raman images were collected at 785 nm excitation and the average Raman spectra were calculated for analysis. Univariate and multivariate spectral analysis were applied for investigation. Raman images were obtained based on the intensity ratios of CH at 1450 cm-1 (matrix) to phosphate at 960 cm-1 (mineral), and carbonate to phosphate (1070/960) ratios. Different algorithms (HCA, K-means cluster and VCA) also used to study the DEJ. The obtained results showed that the width of DEJ is about 5 pm related to univariate method while it varies from 6 to 12 μm based on multivariate spectral technique. Both spectral analyses showed increasing in carbonate content inside the DEJ compared to the dentin, and the amide I (collagen) peak in dentin spectra is higher than DEJ spectra peak.
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    A high resolution extreme ultraviolet spectrometer system optimized for harmonic spectroscopy and XUV beam analysis
    (Melville, NY : American Inst. of Physics, 2019) Wünsche, Martin; Fuchs, Silvio; Weber, Thomas; Nathanael, Jan; Abel, Johann J.; Reinhard, Julius; Wiesner, Felix; Hübner, Uwe; Skruszewicz, Slawomir J.; Paulus, Gerhard G.; Rödel, Christian
    We present a modular extreme ultraviolet (XUV) spectrometer system optimized for a broad spectral range of 12-41 nm (30-99 eV) with a high spectral resolution of λ/Δλ 784 ± 89. The spectrometer system has several operation modes for (1) XUV beam inspection, (2) angular spectral analysis, and (3) imaging spectroscopy. These options allow for a versatile use in high harmonic spectroscopy and XUV beam analysis. The high performance of the spectrometer is demonstrated using a novel cross-sectional imaging method called XUV coherence tomography. © 2019 Author(s).