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Notes: A double-crystal monochromator has been brought into operation at JET to measure absolute wavelengths and intensities of impurity spectral lines in the soft x-ray region from about 0.1 to 2.3 nm. It is capable of operating also during the deuterium-tritium (active) phase of JET because its detector is very effectively shielded against neutrons and hard x rays. The spectrometer has been swept over a wide wavelength range, around characteristic line groups as well as monochromatic line scans.

Notes: Two Bragg spectrometers shared a shielded beamline, and monitored all significant plasma impurities throughout the Joint European Torus (JET) preliminary tritium experiment. The JET Active Phase Double Crystal Monochromator and a Bragg rotor spectrometer together monitored K-shell lines of Be, C, O, and Cl, and L-shell lines from metals such as Ni and Zn, in the wavelength range 0.2–11 nm. Background radiation was recorded during and after discharges, to assess the signal-to-noise ratio, and to monitor any activation or tritium ingress. Bragg spectroscopy was shown to be suitable for all impurities in magnetically confined D–T plasmas, using a thin foil to isolate tritium, and a low f-number shielded beamline. Future improvements to the signal-to-noise ratio are discussed in the context of a next-step machine such as ITER.

Notes: A Bragg spectrometer for monitoring impurity radiation of hydrogenlike carbon and oxygen at the tokamak ASDEX Upgrade is presented. The use of fast multistrip proportional counters allows soft x-ray photon counting with count rates above 1 MHz in a simple arrangement. The absolute calibration was performed using a large area x-ray tube with a LiF anode. The concentrations of both impurities are calculated using the coronal model both for ionization and electron impact excitation. The results of the measurements concerning the long term behavior before and after conditioning of the torus walls by boronization as well as the fast plasma processes are presented. © 1996 American Institute of Physics.

Notes: A spatially scanning, combined vacuum-ultraviolet (VUV) and visible range spectrometer system for the spectroscopy of tokamak plasmas in the ASDEX-Upgrade experiment is described. This system is designed to allow flexible observation of about 2/3 of the boundary plasma using VUV (30–200 nm) and visible range spectrometers viewing along a common line of sight which can be scanned during the plasma discharge by means of a rotatable mirror. From successive spectra recorded using intensified, multichannel photodiode detectors and the recorded position data, spatial profiles of the plasma emission can be reconstructed. Because radiation losses from the boundary plasma can largely be attributed to line emission in the VUV spectral region, this instrument finds application in quantitative studies of radiation loss processes as well as to studies of impurity production and transport. Simultaneous observation in the visible spectral range facilitates an in situ absolute calibration of the VUV instrument by means of the "branching-ratios'' technique. © 1995 American Institute of Physics.

Notes: For absolute soft-x-ray line intensity measurements to deduce elemental concentrations and parameters of magnetically confined plasmas large-area x-ray sources are developed and investigated. These calibration sources use K, L, and M transitions in different elements and cover a wide photon energy (and wavelength) range. From the measured absolute line intensities of these sources the quantum efficiency values of numerous elements for K-, L-, and M-line emission per incident electron are deduced. They represent the basis of simple soft-x-ray monitors for impurities in fusion plasmas. © 1996 American Institute of Physics.

Notes: The highly resolved spectra of the silicon multiplet around 251 nm are studied for plasmas in front of a C/C-SiC target interacting with a nearly cylindrically symmetric low temperature plasma jet. The erosion rates from this target are deduced from the silicon density distribution, which is determined from the line intensity ratios and details of the line profiles. Under the conditions of the plasma parameters in this plasma-target interaction experiment these spectral line parameters depend on the optical depths of the emitting and absorbing silicon atoms along the line of sight. The spectral line central branching ratios of lines with quite different products of absorption oscillator strength and statistical weight are most sensitive to the optical depth. In the case of high plasma jet currents the density of the eroded silicon is found to reach values of up to 5×1018 m−3 in agreement with gravimetric measurements. © 1999 American Institute of Physics.

Notes: The geometrical orientation and curvature radius of the lattice of cylindrically bent crystals in high-resolution x-ray spectrometers for plasma diagnostics are determined locally on the crystal surface by means of a double-crystal device in conjunction with precise transverse displacements of the x-ray beam and accurate angular recordings of the crystal. Surface areas of the crystal which have imperfect orientation and curvature quality and hence contribute to resolving power degradation are thus clearly identified.

Notes: Application of a double-crystal Bragg device with the one crystal swiveling additionally around the x-ray optical axis between the two crystals allows continuous spatial scanning of x-ray line emission from high-temperature plasmas. The main components and physical properties of the monochromator are described, and first results of measurements of spatial profiles of the emission shells of several nickel ionization stages at JET are given.

Notes: Novel microstructures manufactured with high precision and reproducibility are proposed for high-resolution collimators in flat crystal soft x-ray monochromators for plasma spectroscopy. The newly developed technique for this type of collimator is based on surface structuring of foils using profiled microdiamonds. Results of x-ray tests of a microstructure collimator demonstrate that the predicted angular resolution of 5000 at a transmission of about 0.3 can be obtained.

Notes: Abstract: Changes in carbohydrate residue expression and in proteoglycan distribution occur during different stages of tumor development and progression. However, few data concerning carbohydrate residue analysis as performed by lectin histochemistry and proteoglycan distribution of Merkel cell carcinoma, a rare malignant tumor of the skin, have been reported. Hence, lectin- and proteoglycan immunohistochemistry was performed on paraffin wax material of 9 cases of Merkel cell carcinomas characterized by cytokeratin and neurofilament immunohistochemistry. The lectin binding pattern of tumor cells varied between lectins with different sugar binding specificities, while within a given nominal sugar specificity intensities were remarkably similar between tumors from different patients. The most intensive reaction was observed using Con A (mannose/glucose-specific) followed by LCA with the same specificity and the N-Acetyl glucosamine-specific lectins (WGA, UDA, CMA), while no fucose binding sites were detected (UEA-I). In addition, N-Acetyl galactosamine residues were only occasionally detected. The lectin binding pattern of Merkel cell carcinoma cells indicated that predominantly N-linked glycans and not O-linked glycans, typical for mucins of most epithelia, were present. Hence these tumor cells were relatively undifferentiated and resembled stem cells more closely than differentiated epithelia. The tumor stroma was especially evaluated in this study and showed a lectin reaction, which was intermediate between the tumor cells and extra-tumoral stroma. For example, the reactions of N-Acetyl galactosamine-specific lectins were intensive in the extra-tumoral stroma but nearly negative in tumor cells, while the lectin reaction of the intra-tumoral stroma was similar to the cellular reaction. These results indicated an influence of tumor cells on the stromal constituents. Antibodies against chondroitin type glycosaminoglycans reacted with the tumor stroma and the pericellular substance around the tumor cells most intensely in – and around the major tumor septae which, in general, were well vascularized. The most intensive immunoreactivity was detected using the chondroitin-6-sulfate antibody. The cellular and membrane-associated reaction for heparan sulfate was less intensive in comparison to epidermal cells. In conclusion the pattern of lectin-binding sites, the high chondroitin(sulfate) specific reactivity and the relatively low intensity of heparan sulfate immunohistochemistry indicate a low degree of differentiation and high malignity of the tumors, which is consistent with the clinical behavior of Merkel cell carcinomas.