Ultra-precision fabrication of 500 mm long and laterally graded Ru/C multilayer mirrors for X-ray light sources.

X-ray mirrors are needed for beam shaping and monochromatization at advanced research light sources, for instance, free-electron lasers and synchrotron sources. Such mirrors consist of a substrate and a coating. The shape accuracy of the substrate and the layer precision of the coating are the crucial parameters that determine the beam properties required for various applications. In principal, the selection of the layer materials determines the mirror reflectivity. A single layer mirror offers high reflectivity in the range of total external reflection, whereas the reflectivity is reduced considerably above the critical angle. A periodic multilayer can enhance the reflectivity at higher angles due to Bragg reflection. Here, the selection of a suitable combination of layer materials is essential to achieve a high flux at distinct photon energies, which is often required for applications such as microtomography, diffraction, or protein crystallography. This contribution presents the current development of a Ru/C multilayer mirror prepared by magnetron sputtering with a sputtering facility that was designed in-house at the Helmholtz-Zentrum Geesthacht. The deposition conditions were optimized in order to achieve ultra-high precision and high flux in future mirrors. Input for the improved deposition parameters came from investigations by transmission electron microscopy. The X-ray optical properties were investigated by means of X-ray reflectometry using Cu- and Mo-radiation. The change of the multilayer d-spacing over the mirror dimensions and the variation of the Bragg angles were determined. The results demonstrate the ability to precisely control the variation in thickness over the whole mirror length of 500 mm thus achieving picometer-precision in the meter-range.

Improved analyzer multilayers for aluminium and boron detection with x-ray fluorescence.

We have developed improved analyzer multilayers for the detection of aluminium (Al) and boron (B) on silicon (Si) wafers with wavelength-dispersive x-ray fluorescence spectrometers. For the detection of Al on Si wafers we show that WSi(2)/Si and Ta/Si multilayers provide detection limits that are 42% and 60% better, respectively, than with currently used W/Si multilayers. For the detection of B on Si wafers we show that La/B(4)C multilayers improve the detection limit by approximately 28% compared with a conventionally used Mo/B(4)C multilayer.

Multilayer mirror for x rays below 190 eV.

La/B(4)C multilayers have been fabricated by magnetron sputtering for use as x-ray mirrors at energies below 190 eV, particularly for detection of boron K and alpha x rays at 183 eV, their performance has been compared with that of Mo/B(4)C multilayers, which are currently the best-performing multilayers for this energy range. Transmission electron microscopy and synchrotron soft-x-ray reflectometry were used to study the structural quality of the multilayers and their performance as x-ray mirrors. The results show a significant improvement of the peak reflectivity and the spectral purity, indicating that La/B(4)C has a high potential to replace Mo/B(4)C in many x-ray optical applications below 190 eV.

[Transthoracic punch biopsy of mediastinal tumors]. / Transthorakale Stanzbiopsie von mediastinalen Tumoren.

48 consecutive patients underwent biopsy of anterior mediastinal tumors under sonographic guidance by the use of cutting needles up to 2.0 mm in diameter. The results of needle biopsies were compared with the final diagnoses, which was proved with pathologic studies or clinicoradiologic follow-up. In 39 (93%) of 42 malignant tumors malignancy could be readily diagnosed. Examinations of the microcylinders of tissue resulted in correct histologic diagnoses in 32 (76%) of 42 malignant tumors including 13 (81%) of 16 Hodgkin's lymphomas, 6 (66%) of 9 non-Hodgkin lymphomas, 2 (66%) of 3 thymomas and 9 (82%) of 11 carcinomas. All 6 benign lesions were correctly identified. No complications such as hemorrhage or pneumothorax were encountered.

[Postmortem high-resolution computed tomography of the lung. Radiologic-morphologic correlations]. / Postmortale hochauflösende Computertomographie der Lunge. Radiologisch-morphologische Korrelationen.

To establish precise correlations between high-resolution computed tomography (CT) and normal pulmonary anatomy and pulmonary pathology, 49 lungs affected by different diseases were analysed. Post-mortem high-resolution CT scans were compared with the corresponding macroscopic and microscopic pathological findings. For scanning, lungs were inflated and fixed, which avoided any decrease in the structural resolution of pulmonary parenchyma and allowed a topographically exact correlation between CT appearances and morphological changes. After demonstration of the structural details relevant for CT in normal pulmonary parenchyma, an attempt is made to establish the morphological basis of the following CT phenomena: thickening of interlobular septae, increase in pulmonary translucency, consolidation of the non-nodular alveolar and of the nodular type, and changes in the pleural region. Although CT findings in pulmonary lesions are mainly non-specific, knowledge of the corresponding morphological basis is helpful in diagnostic evaluation.