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CCD Detector (ccd + detector)
Selected AbstractsIn situ Grazing Incidence Scattering Investigations During Magnetron Sputtering Deposition of FePt/Ag Thin Films (Adv. Eng.ADVANCED ENGINEERING MATERIALS, Issue 6 2009Mater. The cover picture shows an grazing incidence small angle X-ray scattering pattern of a granular Ag(6nm)-FePt(7.5nm)-Ag-FePt thin film using an in-situ magnetron sputtering chamber measured directly after growth at the Beamline BM20 (ROBL) at the ESRF. The sequential deposition provides separated, faceted FePt nanoislands without any magnetic property degradation and with magnetic moments preferentially oriented parallel to layer surface. The central part of the picture was blocked by a beam stop to avoid an over-saturation of the CCD detector. More details can be found in the article by Jörg Grenzer et al. on page 478. [source] A comparison of a microfocus X-ray source and a conventional sealed tube for crystal structure determinationJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 5 2009Thomas Schulz Experiments are described in which a direct comparison was made between a conventional 2,kW water-cooled sealed-tube X-ray source and a 30,W air-cooled microfocus source with focusing multilayer optics, using the same goniometer, detector, radiation (Mo,K,), crystals and software. The beam characteristics of the two sources were analyzed and the quality of the resulting data sets compared. The Incoatec Microfocus Source (IµS) gave a narrow approximately Gaussian-shaped primary beam profile, whereas the Bruker AXS sealed-tube source, equipped with a graphite monochromator and a monocapillary collimator, had a broader beam with an approximate intensity plateau. Both sources were mounted on the same Bruker D8 goniometer with a SMART APEX II CCD detector and Bruker Kryoflex low-temperature device. Switching between sources simply required changing the software zero setting of the 2, circle and could be performed in a few minutes, so it was possible to use the same crystal for both sources without changing its temperature or orientation. A representative cross section of compounds (organic, organometallic and salt) with and without heavy atoms was investigated. For each compound, two data sets, one from a small and one from a large crystal, were collected using each source. In another experiment, the data quality was compared for crystals of the same compound that had been chosen so that they had dimensions similar to the width of the beam. The data were processed and the structures refined using standard Bruker and SHELX software. The experiments show that the IµS gives superior data for small crystals whereas the diffracted intensities were comparable for the large crystals. Appropriate scaling is particularly important for the IµS data. [source] Tracking reflections through cryogenic cooling with topographyJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3 2006Jeffrey J. Lovelace The mosaic structure of a single protein crystal was analyzed by reflection profiling and topography using highly parallel and monochromatic synchrotron radiation. Fine-,-sliced diffraction images (0.002° stills) were collected using a conventional large-area CCD detector in order to calculate reflection profiles. Fine-,-sliced topographic data (0.002°) stills were collected with a digital topography system for three reflections in a region where the Lorentz effect was minimized. At room temperature, several different mosaic domains were clearly visible within the crystal. Without altering the crystal orientation, the crystal was cryogenically frozen (cryocooled) and the experiment was repeated for the same three reflections. Topographs at cryogenic temperatures reveal a significantly increased mosaicity, while the original domain structure is maintained. A model for the observed changes during cryocooling is presented. [source] Elucidation of zeolite microstructure by synchrotron X-ray diffuse scatteringJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2004B. J. Campbell Single-crystal diffuse scattering measurements can now rapidly probe the three-dimensional structure of subtle defects in microporous framework materials. Diffuse scattering data from natural mordenite crystals are shown to exhibit a complex distribution of weak features which have been mapped out using a synchrotron X-ray source and a CCD detector. Comparison with computer-simulated diffuse scattering patterns yields a detailed three-dimensional columnar defect structure and reveals that roughly one third of the mordenite's columnar defects cooperate to form a block-mosaic pattern of {110} stacking faults. [source] Microbeam small-angle scattering experiments and their combination with microdiffractionJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3-1 2000C. Riekel The brilliance of undulator X-ray sources can be used to develop microfocusing optics for wide-angle (WAXS) and small-angle (SAXS) X-ray scattering. At the ESRF microfocus beamline, a beam size of 10 ,m is obtained by a pinhole collimating system coupled to a double focusing mirror. This allows resolving the first order of collagen (67 nm). Glass capillary optics provides a beam size close to one micron, however, with a more limited resolution. A high-resolution CCD detector allows combined SAXS/WAXS experiments for one detector setting. [source] Hyperspectral imaging combined with principal component analysis for bruise damage detection on white mushrooms (Agaricus bisporus)JOURNAL OF CHEMOMETRICS, Issue 3-4 2008A. A. Gowen Abstract Hyperspectral imaging (HSI) combines conventional imaging and spectroscopy to simultaneously acquire both spatial and spectral information from an object. This technology has recently emerged as a powerful process analytical tool for rapid, non-contact and non-destructive food analysis. In this study, the potential application of HSI for damage detection on the caps of white mushrooms (Agaricus bisporus) was investigated. Mushrooms were damaged by controlled vibration to simulate damage caused by transportation. Hyperspectral images were obtained using a pushbroom line-scanning HSI instrument, operating in the wavelength range of 400,1000,nm with spectroscopic resolution of 5,nm. The effective resolution of the CCD detector was 580,×,580,pixels by 12 bits. Two data reduction methods were investigated: in the first, principal component analysis (PCA) was applied to the hypercube of each sample, and the second PC (PC 2) scores image was used for identification of bruise-damaged regions on the mushroom surface; in the second method PCA was applied to a dataset comprising of average spectra from regions normal and bruise-damaged tissue. In this case it was observed that normal and bruised tissue were separable along the resultant first principal component (PC 1) axis. Multiplying the PC 1 eigenvector by the hypercube data allowed reduction of the hypercube to a 2-D image, which showed maximal contrast between normal and bruise-damaged tissue. The second method performed better than the first when applied to a set of independent mushroom samples. The results from this study could be used for the development of a non-destructive monitoring system for rapid detection of damaged mushrooms on the processing line. Copyright © 2008 John Wiley & Sons, Ltd. [source] In situ observation of water distribution and behaviour in a polymer electrolyte fuel cell by synchrotron X-ray imagingJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2008Taihei Mukaide In situ visualization of the distribution and behaviour of water in a polymer electrolyte fuel cell during power generation has been demonstrated using a synchrotron X-ray imaging technique. Images were recorded using a CCD detector combined with a scintillator (Gd2O2S:Tb) and relay lens system, which were placed at 2.0,m or 2.5,m from the fuel cell. The images were measured continuously before and during power generation, and data on cell performance was recorded. The change of water distribution during power generation was obtained from X-ray images normalized with the initial state of the fuel cell. Compared with other techniques for visualizing the water in fuel cells, this technique enables the water distribution and behaviour in the fuel cell to be visualized during power generation with high spatial resolution. In particular, the effects of the specifications of the gas diffusion layer on the cathode side of the fuel cell on the distribution of water were efficiently identified. This is a very powerful technique for investigating the mechanism of water flow within the fuel cell and the relationship between water behaviour and cell performance. [source] Three-dimensional visualization of the inner structure of single crystals by step-scanning white X-ray section topographyJOURNAL OF SYNCHROTRON RADIATION, Issue 6 2006Taihei Mukaide Visualization of the three-dimensional distribution of the crystal defects of large single crystals of calcium fluoride has been demonstrated by white X-ray section topography using sheet-like X-rays (BL28B2 at SPring-8). An image of the three-dimensional distribution of the crystal defects was reconstructed by stacking section topographs, which expressed the images of cross sections of the sample. The section topographs were recorded using a CMOS flat-panel imager or a CCD detector combined with scintillator (Gd2O2S:Tb) and relay lens system. The section topographs were measured by repeating cycles of exposure and sample translation along the direction perpendicular to the top face of the sample. Using high-brilliance and high-energy white X-rays (,60,keV) efficiently, visualization of the three-dimensional structure of subgrains of a sample of up to 60,mm in diameter was achieved. Furthermore, the three-dimensional distribution of the glide plane in the crystal was visualized by reconstructing the linear contrast of the glide plane. [source] On the use of CCD area detectors for high-resolution specular X-ray reflectivityJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2006P. Fenter The use and application of charge coupled device (CCD) area detectors for high-resolution specular X-ray reflectivity is discussed. Direct comparison of high-resolution specular X-ray reflectivity data measured with CCD area detectors and traditional X-ray scintillator (`point') detectors demonstrates that the use of CCD detectors leads to a substantial (,30-fold) reduction in data acquisition rates because of the elimination of the need to scan the sample to distinguish signal from background. The angular resolution with a CCD detector is also improved by a factor of ,3. The ability to probe the large dynamic range inherent to high-resolution X-ray reflectivity data in the specular reflection geometry was demonstrated with measurements of the orthoclase (001), and ,-Al2O3 (012),water interfaces, with measured reflectivity signals varying by a factor of ,106 without the use of any beam attenuators. Statistical errors in the reflectivity signal are also derived and directly compared with the repeatability of the measurements. [source] First experiments on diffraction-enhanced imaging at LNLSJOURNAL OF SYNCHROTRON RADIATION, Issue 6 2003C. Giles Diffraction-enhanced images have been obtained using two silicon crystals in a non-dispersive set-up at the XRD2 beamline at the Brazilian Synchrotron Light Laboratory (LNLS). A first asymmetrically cut silicon crystal using the (333) reflection vertically expanded the monochromated beam from 1,mm to 20,mm allowing the imaging of the whole sample without movements. A symmetrically cut Si(333) second crystal was used as a Bragg analyzer. Images of biological samples including human tissue were recorded using a direct-conversion CCD detector resulting in enhancement of the contrast compared with absorption-contrast images. [source] The crystallography beamline I711 at MAX,IIJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2000Y. Cerenius A new X-ray crystallographic beamline is operational at the MAX,II synchrotron in Lund. The beamline has been in regular use since August 1998 and is used both for macro- and small molecule diffraction as well as powder diffraction experiments. The radiation source is a 1.8,T multipole wiggler. The beam is focused vertically by a bendable mirror and horizontally by an asymmetrically cut Si(111) monochromator. The wavelength range is 0.8,1.55,Å with a measured flux at 1,Å of more than 1011,photons,s,1 in 0.3,mm × 0.3,mm at the sample position. The station is currently equipped with a Mar345 imaging plate, a Bruker Smart 1000 area CCD detector and a Huber imaging-plate Guinier camera. An ADSC 210 area CCD detector is planned to be installed during 2000. [source] Correctness of a particular solution of inverse problem in rocking curve imagingPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2009Isabella Huber Abstract Local lattice misorientations on crystalline substrates can be visualized by rocking curve imaging. Local deviations from Bragg peak positions are extracted from a series of digital topographs recorded by a CCD detector under different azimuths. Bragg peaks from surface regions such as crystallites with a larger local misorientation overlap on the detector, which requires a back-projection method in order to reconstruct the misorientation components on the sample surface from the measured angular position on the detector planes. From mathematical point of view, the reconstruction problem is an inverse problem. In this paper, we formulate the forward and back-projection problems and we prove the correctness of a particular solution. The usability of the method is demonstrated on a phantom data set. [source] Fast measurements of photoreflectance spectra by using multi-channel detectorPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2009R. Kudrawiec Abstract Photoreflectance (PR) measurements were performed on GaAs- and GaN-based structures in the so called ,bright configuration' where the sample was illuminated by white light (probing beam) instead of monochromatic light as it takes place in the standard configuration, i.e., so-called ,dark configuration'. Within this concept the whole PR spectrum can be measured/processed at the same time using a multi-channel detector (i.e., CCD camera) instead the phase sensitive lock-in detection system with the one-channel detector. In this work PR spectra for Si ,-doped GaAs structure have been measured using both the CCD detector system as well as the standard lock-in technique with the one-channel detector system. GaAs-related Franz,Keldysh oscillations, which are typical of Si ,-doped GaAs structure, have been clearly observed in PR spectra measured by using the two detection systems. In addition, the PR system with the CCD detector has been used to measure PR spectra in the UV spectral region for an InGaN/GaN/Al2O3 structure. In this case, PR resonances related to InGaN and GaN band gap absorption have been clearly observed. Using the PR system with CCD detector the time of PR measurements was reduced to few seconds for both GaAs- and GaN-based structures. It shows that the bright configuration of PR set-up with multi-channel detection system is very promising and perspective in the fast diagnostic of semiconductor structures. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] High-resolution X-ray crystal structure of bovine H-protein at 0.88,Å resolutionACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2010Akifumi Higashiura Recent technical improvements in macromolecular X-ray crystallography have significantly improved the resolution limit of protein structures. However, examples of high-resolution structure determination are still limited. In this study, the X-ray crystal structure of bovine H-protein, a component of the glycine cleavage system, was determined at 0.88,Å resolution. This is the first ultrahigh-resolution structure of an H-protein. The data were collected using synchrotron radiation. Because of limitations of the hardware, especially the dynamic range of the CCD detector, three data sets (high-, medium- and low-resolution data sets) were measured in order to obtain a complete set of data. To improve the quality of the merged data, the reference data set was optimized for merging and the merged data were assessed by comparing merging statistics and R factors against the final model and the number of visualized H atoms. In addition, the advantages of merging three data sets were evaluated. The omission of low-resolution reflections had an adverse effect on visualization of H atoms in hydrogen-omit maps. Visualization of hydrogen electron density is a good indicator for assessing the quality of high-resolution X-ray diffraction data. [source] CTK: A new CCD Camera at the University Observatory Jena,ASTRONOMISCHE NACHRICHTEN, Issue 5 2009M. Mugrauer Abstract The Cassegrain-Teleskop-Kamera (CTK) is a new CCD imager which is operated at the University Observatory Jena since begin of 2006. This article describes the main characteristics of the new camera. The properties of the CCD detector, the CTK image quality, as well as its detection limits for all filters are presented (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Accurate rocking-curve measurements on protein crystals grown in a homogeneous magnetic field of 2.4,TACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2004Daniel Lübbert Differences in mosaicity between lysozyme crystals grown inside and outside a homogeneous magnetic field of 2.4,T and with and without agarose gel were investigated by X-ray diffraction rocking-curve measurements. High angular resolution was achieved using an Si(113) four-reflection Bartels monochromator. The results show that (i) all crystals were highly perfect, (ii) the mosaicities were clearly anisotropic and (iii) the mosaicities varied more strongly within each group of crystals (grown under identical conditions) than the average values across groups. In particular, the effect of the magnetic field on crystal mosaicity was found to be very small. Finally, the spatial distribution of mosaic blocks inside a protein crystal was visualized with a novel diffraction technique using a high spatial resolution two-dimensional CCD detector. [source] Characterization of image plates for neutron diffractionJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 5 2009Clive Wilkinson A method to measure the overall gain and point-spread function of an image-plate detector system (converter, phosphor, readout electronics) online from single-crystal diffraction patterns is derived. Only with a knowledge of these quantities can one estimate without bias the true standard deviations of the observed integrated intensities of Bragg reflections measured with such a detector. The gain corrected for the point-spread function should ideally be approximately 1.0 to avoid loss of data or precision due to the upper and lower limits of digitization of the diffraction patterns. The gain and the point-spread function are derived for several configurations of the three neutron Laue image-plate diffractometers, LADI, VIVALDI and LADI-III, at the Institut Laue,Langevin. The detective quantum efficiencies (DQE) of these instruments have been measured to be 0.16,(1), 0.57,(2) and 0.46,(3), respectively. It has also been found that the DQE is effectively constant for different times of exposure, despite the fading of the photostimulated luminescent signal during that time. While the results described in this paper concern neutron detection by image plates, the method is equally valid for other integrating detectors and radiations, e.g. CCD detectors and X-rays. [source] Elemental abundance analyses with DAO spectrograms: XXX.ASTRONOMISCHE NACHRICHTEN, Issue 4 20102 Ceti (B9 III), 21 Aquilae (B8 II-III), Aquilae (B5 III), Delphini (A2V), The middle B through early A stars Abstract This series of high quality elemental abundance analyses of mostly main-sequence band normal and peculiar B, A, and F stars defines their properties and provides data for the comparison with the analyses of somewhat similar stars and with theoretical predictions. Most use high dispersion and high S/N (, 200) spectrograms obtained with CCD detectors at the long camera of the Coudé spectrograph of the 1.22-m Dominion Astrophysical Observatory telescope. Here we reanalyze 21 Aql with better quality spectra and increase the number of stars consistently analyzed in the spectral range B5 to A2 by analyzing three new stars for this series. In the early A stars the normal and non-mCP stars have abundances with overlapping ranges. But more stars are needed especially in the B5 to B9 range. ,2 Cet on average has a solar composition with a few abundances outside the solar range while both 21 Aql and , Aql have abundances marginally less than solar. The abundances of , Del are greater than solar with a few elements such as Ca being less than solar. It is an Am star (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Elemental abundance analyses with DAO spectrograms: XXXI.ASTRONOMISCHE NACHRICHTEN, Issue 1 200841 Cyg (F5 Ib-II), Her (F2 II), The early F supergiants Abstract This series of high quality elemental abundance analyses of mostly Main Sequence normal and peculiar B, A, and F stars defines their properties and provides data for the comparison with analyses of somewhat similar stars and with theoretical predictions. Most use high dispersion and high S/N (, 200) spectrograms obtained with CCD detectors at the long camera of the 1.22-m Dominion Astrophysical Observatory telescope's coudé spectrograph. Here we expand the range of stars examined to include two relatively quiescent F supergiants. , Her (F2 II) and 41 Cyg (F5 Ib-II) are analyzed as consistently as possible with previous studies. These LTE fine analyses use the ATLAS9 and the WIDTH9 programs of R. L. Kurucz. High signal-to-noise spectrograms and high quality atomic data were employed. The derived values of these photometrically constant stars are somewhat different with the abundances of , Her being somewhat metal-poor and those of 41 Cyg being crudely solar-like. Our analyses indicate that the basic results of Luck & Wepfer (1995) who also studied , Her and 41 Cyg are not likely to be significantly changed by new studies of all their stars. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||