Abstract: Twenty sepiolites of known composition from different origins were analyzed to quantify the variability in structural parameters and its possible relationships with composition and morphology. Morphology SEM analyses led to classify the sepiolites into several groups, beyond the two simple macroscopic or clay groups. X-ray powder diffraction with synchrotron light was used to discuss the variability of the a and b cell parameters with the nature of the cations and occupancy of the octahedral shell. Rietveld refinement using the ideal sepiolite model is performed on sepiolites at two temperatures: 225 {degrees}C (for zeolitically dehydrated sepiolite) and 25 {degrees}C (for hydrated ambient sepiolite). The latter permitted to locate ca. six molecules of the zeolitic H2O within the tunnels. A few samples were selected to evaluate the feasibility and potential of single-crystal diffraction methods: X-ray microdiffraction and electron diffraction. The macroscopic sepiolites gave well-structured and rich X-ray fiber diffraction patterns, in excellent agreement with ab initio simulations. High-quality single-crystal electron diffraction patterns for three axis zones are indexed and compared with simulations. The experimental and modeling results for X-ray microdiffraction and electron diffraction open a new path for quantitative crystallography on sepiolite and other fibrous clays from the sepiolite-palygorskite group.
Abstract: The layout and the optical performance of the SGM branch of the D09 bending-magnet beamline, under construction at SESAME, are presented. The beamline is based on the Dragon-type design and delivers photons over the spectral range 15-250 eV. One fixed entrance slit and a movable exit slit are used. The performance of the beamline has been characterized by calculating the mirror reflectivities and the grating efficiencies. The flux and resolution were calculated by ray-tracing using SHADOW. The grating diffraction efficiencies were calculated using the GRADIF code. The results and the overall shapes of the predicted curves are in reasonable agreement with those obtained using an analytical formula.
Abstract: A new version of the popular X-ray tracing code SHADOW is presented. An important step has been made in restructuring the code following new computer engineering standards, ending with a modular Fortran 2003 structure and an application programming interface (API). The new code has been designed to be compatible with the original file-oriented SHADOW philosophy, but simplifying the compilation, installation and use. In addition, users can now become programmers using the newly designed SHADOW3 API for creating scripts, macros and programs; being able to deal with optical system optimization, image simulation, and also low transmission calculations requiring a large number of rays (>106). Plans for future development and questions on how to accomplish them are also discussed.
Abstract: Abstract Using the voltammetry of microparticles approach, the electrochemical response of complexes prepared with indigo plus different clays in contact with aqueous electrolytes is described. Indigo presents a strong attachment with palygorskite and sepiolite in contrast to a weak attachment to planar clays (montomorillonite and kaolinite). Cyclic voltammetric and chronoamperometric data provide estimates of the variation of the concentration of indigo and dehydroindigo with the depth on clay crystals. The indigoids (indigo and dehydroindigo) penetrate more in palygorskite than in sepiolite, and this penetration is favoured by thermal treatments (very efficient up to 130 °C). The indigo concentration decreases monotonically versus depth, while the dehydroindigo one increases from zero in the external region of the crystals to a maximum at a depth between 40 and 80 nm and then decreasing rapidly. These facts are directly linked to the much higher resistance to acid attack of palygorskite–indigo pigments (Maya Blue) than sepiolite–indigo ones.
Abstract: Maya Blue, an ancient nanostructured organic-inorganic hybrid material resulting from the attachment of indigo, a natural dye, to a phyllosilicate clay, palygorskite, has received considerable attention of late. Despite intensive research, several aspects remain unsolved, in particular the nature of the indigo-palygorskite association. Recent results suggest that the Maya Blue pigment is a complex system in which different topological isomers of various indigoid molecules attached to the palygorskite matrix coexist.
Abstract: We report a preliminary characterization of a blue pigment because its color has been associated to objects found from Aztec and Precolumbian times. The pigment was examined before and after its purification by a variety of techniques: Particle Induced X-ray emission (PIXE), electron paramagnetic resonance (EPR), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy coupled to energy dispersion spectroscopy (SEM-EDS). The relationship of the chemical composition, the spectroscopic signals and the color are discussed.
Abstract: X-ray compound refractive lenses (CRL) are becoming a widespread tool for the generation of microfocus spot sizes at synchrotron beamlines. The calculation of their performance by means of ray-tracing is useful for a rapid estimation of flux, resolution and focusing properties achievable in a beamline, when other optics are present, or simply to study the lens acceptance and focusing in the presence of a particular bending magnet, wiggler or undulator X-ray source. The ray-tracing method presented in this paper has been used to calculate the efficiency of beryllium CRL's using, for the instrument layout, realistic source size and divergence, and usual optics like perfect crystal monochromators. It is shown that the intensity transmitted by the lens, the effective aperture and the gain are in good agreement with analytical formulas. Additional information provided when running the program are the precise shape of beam at the focus, and at any position along the optical axis. For instance the intensity distribution at the CRL entrance and exit planes allows a comparison between the effective and the geometrical apertures. Finally, the method provides a precise value for the lens focal distance, which depends on the CRL length.
Abstract: Some errata in the text of the paper "Thermal and Raman-spectroscopic analysis of Maya blue carrying artifacts, especially fragment IV of the Codex Huamantla" [Thermochim. Acta 456 (2007) 56-63] were noticed, and some historical inaccuracies were revealed. A discussion on the methodological approach using Raman spectroscopy to identify Maya blue in the codex is presented here, not questioning, however, the authenticity of the codex.
Abstract: Particle induced X-ray emission (PIXE) experiments have been carried out at the AGLAE facility (Paris) on several mural samples containing Maya blue from different Prehispanic archaeological sites (Cacaxtla, El Tajin, Tamuin, Santa Cecilia Acatitlan) and from several colonial convents in the Mexican plateau (Jiutepec, Totimehuacan, Tezontepec and Cuauhtinchan). The analysis of the concentration of several elements permitted to extract some information on the technique used for painting the mural, usually fresco. Principal component analysis permitted to classify the samples into groups. This grouping is discussed in relation to geographic and historic data.
Abstract: New approaches of a spectrally tunable backlighting schemes based on a spherically bent crystal are considered. In a contrary to the traditional backlighting scheme, in which the investigated objects should be placed between the backlighter and the crystal, for the considered schemes an object is placed downstream of the crystal, before the tangential or after the sagittal focus and an image of the object is recorded at the distance from the object corresponded to the needed magnification. The magnification is defined by the ratio of the distances form the sagittal focus to the detector and from the object to the sagittal focus. A ray tracing modeling and experimental images of test meshes, obtained at an incidence angles of the backlighter radiation of 10° and 22°, are presented. It is demonstrated that, at incident angles up to 22°, a linear transformation of the obtained astigmatic images allows to reconstruct them with an accuracy (5 - 15%). A spatial resolution around 10 µm in a field of view of some mm2 is achieved, for the spectral range around 9 Å. It is also demonstrated that spherically bent crystals could be used for X-ray imaging of a self emitting plasma structures with a spatial resolution at least 50 µm in a field of view of some square millimeters for angles of incidence up to 22°
Abstract: A novel experimental setup for transmission x-ray microscopy is presented. It is based on the use of a point isotropic x-ray source and a single spherical crystal. The x-ray beam intensity is modulated by the object attenuation, then monochromatized and enlarged using a spherical crystal and, lastly, imaged using a detector downstream of the crystal. We demonstrate by ray tracing technique and experimental testing that this system allows microscopy studies with image resolution better than the dimensions of the source, high magnification ratios, and great field of view. Microscopes using this model can be easily built using different micro x-ray sources, like conventional x- ray tube generators, x-rays emitted by laser generated plasmas or synchrotron radiation. Utilization of spherically bent crystals to obtain high-resolution, large field, monochromatic images in a wide range of Bragg angles (20 degrees < Theta <45 degrees ) is demonstrated for the first time. High quality monochromatic ( delta lambda / lambda ~10/sup -5/-10/sup -3/) images with high magnification about 15-35 times and spatial resolution (<10 mu m) over a large field of view (few mm/sup 2/) were obtained. Some possible applications and preliminary experimental verification of the feasibility of the setup are also presented.
Notes: Cited Reference Count: 22 xD;English xD;Conference Paper
Abstract: In recent years there has been a continuous interest in applying ray- tracing techniques for simulating the performance of neutron instruments. This technique is well known for other applications dealing with photon beams (visible, IR, UV and X-rays). Several codes have been developed by different groups to either calculate, with high accuracy, some particular optical elements of a neutron instrument, or to give rough estimations of the whole instrument including simple models of the individual elements. Our goal is to create an optimised code for neutron optics using accurate descriptions for each optical element. In this paper we will analyse the existing models for treating mosaic crystals monochromators. We will report on the calculated and measured diffraction properties of mosaic copper and pyrolytic graphite crystals, which are two of the most commonly used neutron monochromators.
Notes: Cited Reference Count: 31 xD;English xD;Journal Paper
Abstract: The shadow monochromatic backlighting (SMB) scheme, a modification of the well-known soft X-ray monochromatic backlighting scheme, is proposed. It is based on a spherical crystal as the dispersive element and extends the traditional scheme by allowing one to work with a wide range of Bragg angles and thus in a wide spectral range. The advantages of the new scheme are demonstrated experimentally and supported numerically by ray-tracing simulations. In the experiments, the X-ray backlighter source is a laser-produced plasma, created by the interaction of an ultrashort pulse, Ti:sapphire laser (120 fs, 3-5 mJ, 10/sup 16/ W/cm/sup 2/ on target) or a short wavelength XeCl laser (10 ns, 1-2 J, 10/sup 13/ W/cm/sup 2/ on target) with various solid targets (Dy, Ni+Cr, BaF/sub 2/). In both experiments, the X-ray sources are well localized spatially (~20 mu m) and are spectrally tunable in a relatively wide wavelength range ( lambda = 8-15 AA). High quality monochromatic ( delta lambda / lambda ~10/sup -5/-10/sup -3/) images with high spatial resolution (up to ~4 mu m) over a large field of view (a few square millimeters) were obtained. Utilization of spherically bent crystals to obtain high-resolution, large field, monochromatic images in a wide range of Bragg angles (35 degrees < Theta < 90 degrees ) is demonstrated for the first time.
Notes: Cited Reference Count: 36 xD;English xD;Journal Paper
Abstract: The X-ray reflectivity of a multilayer is a nonlinear function of many parameters (materials, layer thicknesses, densities, roughness). Nonlinear fitting of experimental data with simulations requires to use initial values sufficiently close to the optimum value. This is a difficult task when the space topology of the variables is highly structured, as in our case. The application of global optimization methods to fit multilayer reflectivity data is presented. Genetic algorithms are stochastic methods based on the model of natural evolution: the improvement of a population along successive generations. A complete set of initial parameters constitutes an individual. The population is a collection of individuals. Each generation is built from the parent generation by applying some operators (e.g. selection, crossover, mutation) on the members of the parent generation. The pressure of selection drives the population to include "good" individuals. For large number of generations, the best individuals will approximate the optimum parameters. Some results on fitting experimental hard X-ray reflectivity data for Ni/C multilayers recorded at the ESRF BM5 are presented. This method could be also applied to the help in the design of multilayers optimized for a target application, like for astronomical grazing-incidence hard X-ray telescopes.
Notes: Cited Reference Count: 31 xD;English xD;Conference Paper
Abstract: Many software programs are available on the market for the design of optical instruments. However, most of them are not suitable for modeling X-ray optical elements. The simulation of the X-ray source characteristics (emission, geometry) strongly depends on the type of generator used (synchrotron insertion devices, FEL, X-ray tube, laser- generated plasma, etc.). The optical elements are usually grazing mirrors, multilayers and crystals, with very different characteristics from optical elements used in other photon ranges. In addition, the reflectivities of such optical devices must be calculated taking into account tabulated optical constants. In the last years we have developed a new approach for creating a common tool for X-ray optics and sources modeling, lumping together small programs from different origins and authors, adding an unified X-ray database and gluing all this in a user-friendly and powerful data manipulation environment. The result is the XOP code which is now used in many synchrotron facilities. In addition to the first level calculations available in XOP, we have incorporated an interface to the popular X-ray tracing code SHADOW that allows the simulation of the complete beamline and produces accurate values of beam sizes, divergences, flux and energy resolution. I review the present state of XOP and the SHADOW Visual Interface. I then present the plans for a new version in preparation. Then I discuss new ideas and possible requirements for simulating the forthcoming X-ray optics for fourth generation X-ray sources.
Notes: Cited Reference Count: 22 xD;English xD;Conference Paper
Abstract: Section topographs recorded at different spatial locations and at different rocking angles of a highly oriented pyrolytic graphite (HOPG) crystal allow three-dimensional maps of the local angular-dependent scattering power to be obtained. This is performed with a direct reconstruction from the intensity distribution on such topographs. The maps allow the extraction of information on local structural parameters such as size, form and internal mosaic spread of crystalline domains. This data analysis leads to a new method for the characterization of mosaic crystals. Perspectives and limits of applicability of this method are discussed.
Notes: Cited Reference Count: 14 xD;English xD;Journal Paper
Abstract: Summary form only given, as follows. The new advantages of well-known combination of a laser-produced X-ray plasma source and spherically bent crystal for the soft X-ray region backlighting scheme were experimentally demonstrated and theoretically modelling by ray-tracing package SHADOW. The X-ray source was produced by heating radiation of Ti:sapphire laser (120 fs, 3-5 mJ, laser flux density 10/sup 13/ W/cm/sup 2/) or XeCl laser (1-1.3 J, 10 ns, laser flux density 10/sup 13/ W/cm/sup 2/) with repetition 10 Hz at different solid targets (Mg, Fe, Ni, Dy, BaF/sub 2/). X-ray source spot size on the target was well localised both spatially (~20 mu m) and temporally (1 ps-10 ns, depend of used laser) and is spectrally tunable in a relatively wide range (6- 19 AA). High quality monochromatic ( delta lambda / lambda ~10/sup -5/- 10/sup -3/) images with high spatial resolution (up to ~4 mu m) and in a large field of view (few mm) were obtained for different wavelengths using the same spherically bent crystal. It was demonstrated at first time that the spherically bent crystals can be sufficiently used for obtaining high-resolution, large-field, monochromatic images in a wide range of Bragg angles ( theta =40-90 degrees ), thus spherically bent crystals are universal for very wide wavelength selection, what is very important for many applications. Obtained experimental results were independently confirmed by ray-tracing modelling for different radius of crystal curvatures, Bragg angles and linear magnification of images.
Notes: Cited Reference Count: 0 xD;English xD;Conference Paper
Abstract: We have measured the hard X-ray reflectivity and imaging performance from xD; depth graded W/Si multilayer coated mirror segments mounted in a single xD; reflection cylindrical prototype for the hard X-ray telescopes to be flown on the xD; High Energy Focusing Telescope (HEFT) balloon mission. Data have been xD; obtained in the energy range from 18 - 170 keV at the European Synchrotron xD; Radiation Facility and at the Danish Space Research Institute at 8 keV. The xD; modeling of the reflectivity data demonstrate that the multilayer structure can xD; be well described by the intended power law distribution of the bilayer xD; thicknesses optimized for the telescope performance and we find that all the xD; data is consistent with an interfacial width of 4.5 angstroms. We have also xD; demonstrated that the required 5% uniformity of the coatings is obtained over xD; the mirror surface and we have shown that it is feasible to use similar W/Si xD; coatings for much higher energies than the nominal energy range of HEFT xD; leading the way for designing Gamma-ray telescopes for future astronomical xD; applications. Finally we have demonstrate 35 arcsecond Half Power Diameter xD; imaging performance of the one bounce prototype throughout the energy xD; range of the HEFT telescopes.
Abstract: The X-ray reflectivity of a multilayer is a non-linear function of many parameters (materials, layer thickness, density, roughness). Non-linear fitting of experimental data with simulations requires the use of initial values sufficiently close to the optimum value. This is a difficult task when the topology of the space of the variables is highly structured. We apply global optimization methods to fit multilayer reflectivity. Genetic algorithms are stochastic methods based on the model of natural evolution: the improvement of a population along successive generations. A complete set of initial parameters constitutes an individual. The population is a collection of individuals. Each generation is built from the parent generation by applying some operators (selection, crossover, mutation, etc.) on the members of the parent generation. The pressure of selection drives the population to include "good" individuals. For large number of generations, the best individuals will approximate the optimum parameters. Some results on fitting experimental hard x-ray reflectivity data for Ni/C and W/Si multilayers using genetic algorithms are presented. This method can also be applied to design multilayers optimized for a target application.
Notes: Cited Reference Count: 12 xD;English xD;Conference Paper
Abstract: We have performed x-ray specular reflectivity and scattering measurements of xD; thermally slumped glass substrates on x-ray diffractometers utilizing a rotating xD; anode x-ray source at the Danish Space Research Institute (DSRI) andsynchrotron radiation at the European Synchrotron Radiation Facility (ESRF) optics Bending Magnet beamline. In addition, we tested depth graded W/Si multilayer-coated slumped glass using x-ray specular reflectivity measurements at 8.048 keV and 28 keV and energy-dispersive measurements in the 20-50 keV rang at a double-axis diffractometer at the Orsted Laboratory, University of Copenhagen. The thermally slumped glass substrates will be used to fabricate the hard x-ray grazing incidence optics for the High-Energy Focusing Telescope. We compared the measurements to the SODART- mirrors from the SRG telescope mission program. The surface scatter measurement of the thermally slumped glass substrates yields Half Power Diameters (HPD's) of single- bounce mirrors of full-illuminated lengths of approximately 40 arcseconds for typical substrates and as low as approximately 10 arcseconds for the best substrates, whereas the SODART mirrors yields HPD's of approximately 80 arcseconds with very little variation. Both free-standing glass substrates and prototype mounted and multilayer-coated optics were tested. The result demonstrate that the surface scatter contribution, plus any contribution from the mounting procedure, to the Half Power Diameter from a telescope using the slumped glass optics will be in the subarcminute range.In addition we measured low surface microroughness, yielding high reflectivity, from the glass substrates, as well as from the depth graded W/Si multilayer-coated glass.
Abstract: Ray-tracing simulations, validated by exptl. results, demonstrate that high intensity collimated x-ray beams can be produced from an isotropic x-ray source. A spherically bent mica crystal was used to collimate and monochromatize x rays emitted by a femtosecond laser-produced plasma. The result is a short pulse x-ray beam with a high degree of collimation (less than 1 mrad divergence), good spectral resoln. (10-2<Dl/l<10-4), and tunability over a wide spectral range. The role of the exptl. parameters in the resulting beam divergence is thoroughly analyzed by ray-tracing modeling. These simulations are validated by test expts. The ray-tracing calcns. define a set of boundaries in the exptl. parameters, which will guarantee the achievement of collimated beams better than 1 mrad in further expts. [on SciFinder (R)]
Notes: BP 220,European Synchrotron Radiation Facility,Grenoble,Fr. xD;Journal xD;0034-6748 xD;written in English.
Abstract: Highly oriented pyrolytic graphite is a very efficient and well-known X-ray and neutron monochromator. The crystal macroscopic properties are determined by its microscopic structure. Our aim is to study the crystal internal structure and correlate it with the crystal optical behavior. We studied the texture of the crystal, in particular its spatial homogeneity, for different samples using X-ray diffraction topography. The experiment was performed at the ESRF beamline BM5 using a laminar 18 keV monochromatic beam. Several samples supplied by different manufacturers have been studied. Images of (002) reflected beam have been acquired at the Bragg angle for each sample, using a phosphor coated CCD digital detector. Contrast profiles have been obtained, and exponential fits has been performed allowing to deduce the secondary extinction coefficient. It has been found that some samples are quite perfect and the results agree with ideally imperfect crystals model. Other samples present well defined granular macrostructures (with dimensions of tens of microns) superposed to the well-known Gaussian-like crystallite distribution. The different behavior between different samples should be explained in terms of sample internal structure, which is also related to the different graphitization process used by manufacturers.
Notes: Cited Reference Count: 17 xD;English xD;Conference Paper
Abstract: SINBAD, the first beamline in Italy designed to work in the far- and mid-infrared region, is being installed on DA Phi NE storage ring, the new Phi -factory at Laboratori Nazionali di Frascati. DA Phi NE, first injected in September 1997, will work at 0.51 GeV with a beam current in the range 2-5 A. The infrared synchrotron radiation extracted from a bending magnet is expected to be more brilliant than a black body at 2000 K up to three orders of magnitude in the wavelength range 10-1000 mu m. The optical layout of SINBAD, fully designed by ray tracing simulation, includes six mirrors placed in a 18 m long beamline. The infrared radiation is first focused on a wedged diamond window and then re-focused on the entrance of a Michelson interferometer. Diffraction effects and mirror roughness, as well as optical aberrations, have been evaluated.
Notes: Cited Reference Count: 28 xD;English xD;Journal Paper
Abstract: XOP (X-ray OPtics utilities) is a graphical user interface (GUI) to run computer programs that calculate basic information needed by synchrotron radiation beamline scientists and engineers. It can also be used as a front end for specific codes or packages for data analysis and data reduction (XAFS, surface crystallography, etc.). XOP contains a customized database for optical and atomic constants. It has a flexible design and new applications may be added. The capabilities of XOP, including those related to simulations of crystal diffraction profiles and multilayer reflectivities, are summarized. We discuss the most recent developments to be included in XOP version 2.0. A few other examples of typical calculations are: insertion device (undulator and wiggler) spectra and angular distributions, mirror and multilayer reflectivities, and crystal diffraction profiles. The computer programs are executed and the results are analyzed within the GUI, which makes them fast and easy to use. The XOP interface is written in the Interactive Data Language (IDL) from Research Systems Inc., and it runs on the Unix (HP, Sun, Linux, DEC-Alpha, and Silicon Graphics), and on the Windows 95/NT operating systems. It has been built with an IDL license embedded and is available under some limited conditions free of charge from the authors.
Notes: Cited Reference Count: 34 xD;English xD;Conference Paper
Abstract: A review of the physical models for crystal optics in a ray tracing program is presented. X-ray monochromators and analyzers for synchrotron radiation applications in both Bragg (reflection) and Laue (transmission) geometries can be simulated with this method. Ray tracing calculations for several high-resolution and focusing geometries are presented, demonstrating the suitability of the ray tracing method for the design and optimization X-ray crystal optics. Possible applications to study the crystal effects on partially coherent beams are also outlined. All these systems have been modeled in the framework of the ray tracing program SHADOW. For increasing the visual and post-processing functionality of SHADOW we developed a front-end library an a Visual User Interface available from the author.
Notes: Cited Reference Count: 34 xD;English xD;Conference Paper
Abstract: X-ray instruments with mosaic crystals are proposed and used in many applications in synchrotron radiation, medical physics and astrophysics. These crystals present a parafocusing of the X-ray beam in the diffraction plane, which is thoroughly analyzed in this paper. We studied the evolution of the cross-section of the diffracted beam, using several samples of Highly Oriented Pyrolythic Graphite crystals coming from different suppliers. The experiment has been performed at the European Synchrotron Radiation Facility (beamline BM5). The results clearly show a parafocusing effect in the 1:1 magnification ratio along the diffraction plane and a defocusing effect along the perpendicular plane. The secondary extinction coefficient is also measured.
Notes: Cited Reference Count: 18 xD;English xD;Conference Paper
Abstract: A set of IDL functions and procedures to perform basic XAFS data analysis has been developed. XAID provides the necessary tools to perform background substraction, Fourier transforms, Fourier filtering, etc. The library routines can be used as modules to be included in the users's customized programs or for creating widget applications. Stand- alone main programs and graphical user interfaces to perform standard data analysis are also presented.
Notes: Cited Reference Count: 4 xD;English xD;Conference Paper
Abstract: In this paper we analyse the macroscopic orientation induced on a nematic liquid crystal by a periodic saw-toothed surface in the micrometric range and with variable slope. We calculate the critical slope, which corresponds to the planar-homeotropic transition, for different values of the elastic anisotropy and with boundary conditions varying from relatively weak anchoring [W=10/sup -4/ erg/cm/sup 2/] to relatively strong anchoring [W=10 /sup -1/ erg/cm/sup 2/] conditions. The present study is carried out by means of a finite element method approach.
Notes: Cited Reference Count: 14 xD;English xD;Journal Paper
Abstract: We report on the status of the first Italian Infrared Synchrotron Radiation Beamline SINBAD (Synchrotron INfrared Beamline At DA Phi NE), that has been designed to work at wavelengths greater than 10 mu m. SINBAD is being installed on DA Phi NE, the new collider of the Laboratori Nazionali di Frascati designed to work at 0.51 GeV with a beam current of 2 to 5 A. The infrared radiation extracted from a bending magnet under an angle of 50*50 mrad will be two orders of magnitude more brilliant than that of a black body at 2000 K at a wavelength of 100 mu m. The beamline layout, which consists of two planar mirrors, two toroidal mirrors and one aspherical mirror, has been designed by ray tracing simulation. In this layout one ellipsoid focuses the radiation on a wedged CVD diamond-film window, the beam is then re-focused again on the entrance of an interferometer. With a calculated transmittance of the optics between 60% and 80% at 50 mu m, this beamline will allow experiments which require a very high brilliance in the far infrared.
Notes: Cited Reference Count: 18 xD;English xD;Conference Paper
Abstract: XOP (X-ray optics utilities) is a graphical user interface (GUI) created to execute several computer programs that calculate the basic information needed by a synchrotron beamline scientist (designer or experimentalist). Typical examples of such calculations are: insertion device (undulator or wiggler) spectral and angular distributions, mirror and multilayer reflectivities, and crystal diffraction profiles. All programs are provided to the user under a unified GUI, which greatly simplifies their execution. The XOP optics applications (especially mirror calculations) take their basic input (optical constants, compound and mixture tables) from a flexible file-oriented database, which allows the user to select data from a large number of choices and also to customize their own data sets. XOP includes many mathematical and visualization capabilities. It also permits the combination of reflectivities from several mirrors and filters, and their effect, onto a source spectrum. This feature is very useful when calculating thermal load on a series of optical elements. The XOP interface is written in the IDL (interactive data language). An embedded version of XOP, which freely runs under most Unix platforms (HP, Sun, Dec, Linux, etc) and under Windows95 and NT, is available upon request.
Notes: Cited Reference Count: 27 xD;English xD;Conference Paper
Abstract: The properties of a monochromatic X-ray backlighting system based on a spherically bent crystal were investigated. Simulations of spatial resolution for spherically bent crystals with different radius of curvature and for several wavelengths of incidence radiation were done using the ray-tracing method. Test experiments were carried out to demonstrate the high spatial resolution using the incoherent soft X-ray radiation produced by laser- and X-pinch plasmas. Both experimental and theoretical results show that a spatial resolution of at least 4 mu m can be obtained in a field of view ranging from a few mm to cm. The narrow spectral band of the diffracted beam ( Delta lambda / lambda ~3.10/sup -4/), the high efficiency of the presented scheme and the possibility of significantly reducing the self radiation of the studied object make it one of the most promising backlighting systems. This scheme permits the essential reduction of requirements of the source of radiation and could be a less costly alternative to using X-ray lasers for such purposes.
Notes: Cited Reference Count: 21 xD;English xD;Journal Paper
Abstract: Ray-tracing plays an essential role for the design of a synchrotron radiation beamline optics. Nevertheless, it can also be extremely useful during the commissioning phase of a beamline. At that moment, it is possible to include real surface figure errors in the computer simulation of the optical devices. The resulting focal spot size and photon flux values are the final targets for the experimental optimization and alignment of the optics setup. We report on extensive ray-tracing of the mirror systems of the two beamlines placed at the ESRF insertion device 12. Slope errors measured after mirror delivery are included in the calculations. It is demonstrated how slope errors with characteristic periodicity between 1 and ca. 1/20 of the mirror length can affect the focal spot shape, size and position. In particular, they can create structures or satellites in the focal spot. The distortions from the ideal shape are generated by the polishing process itself and are intrinsic to each single mirror. Comparison between the effects of slope errors in ray-tracing using either real (measured) surfaces or are also reported.
Notes: Cited Reference Count: 16 xD;English xD;Conference Paper
Abstract: Various theoretical methods for calculating diffraction profiles of perfect crystals are available in literature. Although these methods hold within certain validity ranges due to their inherent approximations, they constitute the current state-of-the-art of numerical computation of diffraction profiles. In this paper we summarize the theory of Zachariasen for flat crystals, the multi- lamellar approximation for bent crystals and the Penning-Polder approximation for bent Laue crystals. Some examples of their results are presented. Another method to calculate the diffraction profile consists in solving the Takagi-Taupin equations. The finite difference method, that provides a numerical solution of these equations, is briefly discussed. A new method for solving numerically these equations using the finite element method is proposed. This method is very flexible, because it can consider a crystal with an arbitrary shape and cover the case of critical regime (i.e., inhomogeneities and deformations) with fine elements. In addition, it can couple naturally the diffraction calculation with thermal or mechanical crystal deformations. These deformations are generally induced by the X-ray beam (heat load), the crystal bender (mechanical stress) or are intrinsic to the crystal (inhomogeneities, impurities, dislocations, etc.). An example of the feasibility of this method is shown.
Notes: Cited Reference Count: 33 xD;English xD;Conference Paper
Abstract: A graphical user interface, using the Interactive Data Language (IDL) widget toolkit, for calculation of spectral properties of synchrotron radiation sources and for interaction of X-rays with optical elements has been developed. The interface runs presently on three different computer architectures under the Unix operating system-the Sun-OS, the HP-UX, and the DEC-Unix operating systems. The point-and-click interface is used as a driver program for a variety of codes from different authors written in different computer languages. The execution of codes for calculating synchrotron radiation from undulators, wigglers, and bending magnets is summarized. The computation of optical properties of materials and the X-ray diffraction profiles from crystals in different geometries are also discussed. The interface largely simplifies the use of these codes and may be used without prior knowledge of how to run a particular program.
Notes: Cited Reference Count: 8 xD;English xD;Conference Paper
Abstract: Different optical layouts for a beamline that extracts infrared synchrotron radiation from a bending magnet are discussed, and their performances are compared by use of ray-tracing simulations. Specific results are presented for SINBAD, the beamline to be mounted on the new Frascati collider DA Phi NE.
Notes: Cited Reference Count: 7 xD;English xD;Conference Paper
Abstract: A workshop on X-ray optics and ray tracing was held at the Synchrotron Radiation Instrumentation conference held at Argonne, on October 18 1995. The object of the workshop was to exchange experience in ray- tracing calculations between the largest synchrotron radiation facilities. The introduction was carried out by France Cerrina, who made a review presentation of SHADOW, the only ray-tracing code that can be used for almost all the synchrotron radiation applications and surely the most wide-spread and complete one. Then a total of seven speakers presented in short talks (20 minutes) their experience in the use of SHADOW at their respective facilities, their developments, suggestions, wishes, and complaints about some points of the package. Some of the presentations are available as contributed papers to the SRI'95 proceedings. In general, the speakers (representing all the US Department of Energy synchrotron radiation sources) felt that the program was an essential part of the facilities experimental development.
Notes: Cited Reference Count: 0 xD;English xD;Conference Paper
Abstract: The performance of a diamond double-crystal monochromator for the TROIKA II station at the ESRF was studied. Two (111) oriented diamond crystals for Bragg geometry (120 mu m and 500 mu m thick) were combined in a nondispersive horizontal scattering geometry and characterized in the white Troika undulator beam. The observed rocking curves were slightly broadened due to nonuniform defect distributions present in the crystals. No heat-load-induced broadening was found. The measured reflectivities compared well to the calculated values, and it was shown that a double-crystal Bragg monochromator can replace a single- reflection Laue monochromator without loss in flux.
Notes: Cited Reference Count: 11 xD;English xD;Conference Paper
Abstract: The ESRF is the first operational third-generation synchrotron radiation hard-X-ray source. Since the beginning of its construction (1988), the ray-tracing technique proved to be an essential computer tool for the beamline optics design. The optical systems of most beamlines have been simulated by ray tracing in order to optimize the optics, fully understand their properties, and check if operation performances were as expected. In this paper, a short compilation of the experience with ray tracing and optics simulation codes at the ESRF, as well as some other in-house developments, is presented.
Notes: Cited Reference Count: 29 xD;English xD;Conference Paper
Abstract: In the article \"Comments on the use of asym. monochromators for x-ray diffraction on a synchrotron source,\" by Colin Nave, Ana Gonzalez, Graham Clark, Sean McSweeney, Stewart Cummings, and Michael Hart, Rev. Sci. Instrum. 66, 2174 (1995), paragraph II, the authors' unfamiliarity with our modeling codes leads them to claim that our approach to treat bent-asym. cut crystals in ray tracing calcns. is incorrect. Since SHADOW is a widely used code, it is important to correct any misunderstandings, and we give here arguments to demonstrate that our approach is perfectly valid, and the arguments used by the authors to criticize our method are based on an unwarranted conclusion extd. from one of our previous articles. We show that SHADOW, when properly run, treats the cases raised exactly. Indeed, their arguments provide a nice benchmark test for verifying the accuracy of SHADOW. [on SciFinder (R)]
Notes: European Synchrotron Radiat. Fac.,Grenoble,Fr. xD;Journal; Letter xD;0034-6748 xD;written in English.
Abstract: The actual source area of a bending magnet emitting in the infrared range, has been calculated for the double annular Phi -factory for nice experiments (DA Phi NE) under construction at Frascati. "Geometrical" broadening has been included. The actual brilliance ratio defined as the ratio between the brilliance of a synchrotron source and that of a blackbody, has been also evaluated for DA Phi NE and compared with the Brookhaven NSLS source.
Notes: Cited Reference Count: 13 xD;English xD;Conference Paper
Abstract: A Laue-type curved monochromator has been used for the first time for energy-dispersive XAFS spectroscopy on a synchrotron beam line. Experiments at the Pd K-edge at 24.35 keV photon energy have been performed at the DEXAFS/HASYLAB station. The quality of the XAFS spectra proved to be superior to spectra measured with silicon crystals in the dispersive Bragg geometry. In this case an asymmetric broadening of the reflectivity profile leads to strong distortions of the near edge fine structure and a reduction in the spectral resolution. XAFS spectra measured in the Laue and Bragg geometry are compared. The reflectivity profiles have been calculated using the dynamical theory.
Notes: Cited Reference Count: 4 xD;English xD;Conference Paper
Abstract: A double-focusing small-angle X-ray scattering camera has been installed at the European Synchrotron Radiation Facility. The camera uses a low- beta undulator as insertion device. Stable operation has been demonstrated at 13 keV. A beam size at the sample position in the range of 100-200 mu m and a flux in excess of 10/sup 10/ Ph/s have been obtained. The camera allows to resolve the first order of collagen (67 nm).
Notes: Cited Reference Count: 31 xD;English xD;Journal Paper
Abstract: In a Bonse-Hart camera, a set of two or more grooved (channel cut) perfect crystals are used to provide a very high angular resolution experiment. The resulting multireflection profiles can be calculated in a first approximation by the dynamical theory of diffraction, where usually only coherent scattering is considered. In addition, there is experimental evidence of incoherent Compton scattering (ICS) and thermal diffuse scattering (TDS) contributions. Such contributions are especially important when performing small angle scattering experiments where intensities in an interval of ten orders of magnitude are often recorded. We propose and analyze here the use of thin (a few micrometers) crystals for a Bonse-Hart camera in order to decrease the TDS and ICS components, thus to increase the performances of the device. However, using thin crystals causes the occurrence of interference (Pendellosung) fringes which degrades the instrument resolution. We study in this paper the possible elimination of Pendellosung fringes by angularly offsetting one or more crystals with respect to the others. Optimizing the offset value, the Pendellosung oscillations of the crystals interfere destructively, then significantly reducing their contribution to the total resolution function.
Notes: Cited Reference Count: 11 xD;English xD;Conference Paper
Abstract: The focused white beam on beam line 3 is produced by the joint action of a undulator insertion device coupled to a tunable toroidal mirror. It is shown that this combination gives the highest possible flux d. at the sample position. The intensity is sufficient to record single bunch Laue patterns from smaller proteins contg. up to 1200 reflections per image. The possibilities of increasing the flux further by going to mini gap undulators are also discussed. A comparison between a low b and a high b undulator is discussed to boost the time resolving power in monochromatic expts. [on SciFinder (R)]
Notes: CAN 123:280101 xD;9-5 xD;Biochemical Methods xD;European Synchrotron Radiation Facility,Grenoble,Fr. xD;Journal xD;0277-786X xD;written in English.
Abstract: Perfect crystals in transmission (Laue) geometry can effectively be used for X-ray monochromators. Perfect Laue crystals show an interesting focusing effect when the incident beam is white and divergent. This focusing is highly dependent on the beam divergence and on the energy bandpass of the crystal. The aim of this work is to study whether this property can be used for focusing a synchrotron X-ray beam, and to obtain quantitatively the beam dimensions of the resulting monochromatic beam. We have experimentally measured the size of an undulator beam after diffraction from a diamond crystal in Laue geometry, and we analyzed and explained the results by comparison with ray tracing.
Notes: Cited Reference Count: 0 xD;English xD;Conference Paper
Abstract: NPI is an interactive program for EXAFS (extended X-ray absorption fine structure) data analysis. It contains the basic tools for the EXAFS data extraction and processing (background substraction, Fourier Transform, Fourier filtering, fitting, etc.). NPI provides the maximum of simplicity of use because of its numbered menus. NPI can efficiently compare and fit experimental EXAFS spectra with a model signal, which could be obtained from either a reference compound or from ab initio calculations. For the last option NPI can read the output of the most sophisticated theoretical programs in the curve-wave formalism, such as FEFF and MSXAS. NPI runs under most of the UNIX systems and VAX/VMS; also a PC version is envisaged.
Notes: Cited Reference Count: 7 xD;English xD;Journal Paper
Abstract: The undulator X-ray source is an ideal source for many applications: the beam is brilliant, highly collimated in all directions, quasi- monochromatic, pulsed and linearly polarized. Such a precious source can feed several independently operated instruments by utilizing a downstream series of X-ray transparent monochromator crystals. Diamond in particular is an attractive monochromator as it is rather X-ray transparent and can be fabricated to a high degree of crystal perfection. Moreover, it has a very high heat conductivity and a rather small thermal expansion so the beam X-ray heat load problem is easily overcome. We describe a possible setup with three successive monochromators. We present data and analysis for focusing the beam in both the horizontal and vertical direction and discuss the focusing properties in both the Lane and Bragg geometry.
Notes: Cited Reference Count: 20 xD;English xD;Journal Paper
Abstract: DA Phi NE, the new storage ring under construction at Frascati, can also be used as a powerful synchrotron radiation source in the infrared domain, where it is much more brilliant than a blackbody. Ray-tracing calculations of different optical setups at different wavelengths are reported.
Notes: Cited Reference Count: 9 xD;English xD;Conference Paper
Abstract: Modifications are presented to the BRAGG program, using SHADOW, permitting calcg. diffraction profiles of org. crystals. The validity of the modifications was made in comparison of the results obtained with previous results for the program for a Si crystal and with some org. crystals (acid phthalates, PET, etc.). [on SciFinder (R)]
Notes: CAN 123:71016 xD;75-10 xD;Crystallography and Liquid Crystals xD;Serv. Conception Exptl. Mesure,CEA,Bruyeres-le-Chatel,Fr. xD;Journal xD;0003-4169 xD;written in French.
Abstract: We present here a modeling of Laue crystals in the framework of the ray-tracing program SHADOW (B. Lai and F. Cerrina, Nucl. Instr. and Meth. A 246 (1986) 337 [1]). In this program, the equations of the dynamic theory of x-ray diffraction have been coded to allow calcns. of the diffracted intensity distributions. For thin and weakly absorbing crystals these profiles exhibit strong oscillations as a consequence of the Pendelloesung effect. These patterns also produce an oscillating value of the integrated intensity as a function of photon energy. The thickness of the crystal can be adjusted to optimize its optical performance for a given energy range. We analyze different examples of thickness optimization for such crystals. The performance of a Laue-Bragg monochromator is then compared to that of a std. Bragg-Bragg monochromator for a beamline configuration. [on SciFinder (R)]
Notes: CAN 121:266879 xD;73-6 xD;Optical, Electron, and Mass Spectroscopy and Other Related Properties xD;European Synchrotron Radiation Facility, BP 220,Grenoble,Fr. xD;Journal xD;0168-9002 xD;written in English. xD;7440-21-3 (Silicon); 7782-40-3 (Diamond) Role: DEV (Device component use), USES (Uses) (modeling perfect crystals in transmission geometry for synchrotron radiation monochromator design)
Abstract: Two undulator beam lines will be available at the ESRF for microdiffraction/small-angle scattering (beam line 1) and time-resolved small-angle scattering/biological crystallography (beam line 4). In both cases a separate function optics with a double monochromator and a double focusing mirror have been selected. The general design principles of the two cameras, end station, and data acquisition systems foreseen are discussed.
Notes: Cited Reference Count: 34 xD;English xD;Conference Paper
Abstract: Mosaic crystals provide an interesting choice for synchrotron radiation monochromators under certain conditions. They show a wider and lower reflectivity curve than perfect crystals, but a higher integrated reflectivity. Some mosaic crystals such as graphite or beryllium could be considered as monochromators or premonochromators for third generation synchrotron radiation machines (Sincrotrone Trieste, European Synchrotron Radiation facility, etc.). In order to assess these possibilities, the authors have implemented a new mosaic crystal part in the ray tracing code SHADOW. The effect of the random distribution of the crystallites in a mosaic crystal can be analyzed efficiently with a Monte Carlo method. Taking into account the random distribution of the crystal planes, modeled as a Gaussian of standard deviation kappa , it is possible to reproduce the well known focusing and defocusing properties of these crystals. For reflectivity calculations the authors have implemented in the computer code the mosaic crystals theory of Zachariasen. As secondary extinction is not negligible in mosaic crystals, they have also included the penetration effect of the X-ray beam inside the crystal.
Notes: Cited Reference Count: 6 xD;English xD;Conference Paper
Abstract: Asymmetrically cut crystals are interesting for use in synchrotron radiation monochromators because of their good energy resolution characteristics and their focusing properties. Ray tracing codes, such as SHADOW, are very efficient in the design and development of new optical devices. In order to determine the convenience of using asymmetrically cut crystals for X-ray monochromators, SHADOW has been extended to include these kinds of crystals. The physical approach to ray tracing asymmetrically cut crystals is based on the coexistence of two periodic structures. One of these is the bulk periodic structure of the Bragg planes. Such a structure determines the existence of a rocking curve near the Bragg condition, and is implemented in SHADOW following the Darwin-Prins formalism of the dynamical theory of diffraction. The second periodic structure is a one-dimensional grating on the crystal surface, formed by the truncation of the lattice planes with the surface. This grating is responsible for the focusing properties of these crystals and plays an essential role in determining the trajectory of the rays. The combination of an asymmetric crystal and a nonplanar surface can be easily achieved by bending (Johann case) to provide improved properties. More complex cases such as the ground- bent crystals (i.e., Johansson geometry) can be considered as a particular case of asymmetrical crystals in which the angle between the Bragg planes and the surface change along the crystal surface. All these cases have been implemented in SHADOW.
Notes: Cited Reference Count: 11 xD;English xD;Conference Paper
Abstract: Ray-tracing calcns. are playing an essential role in the design of synchrotron radiation beamlines. In particular, for the new generation of synchrotron radiation machines that will produce high brightness x-ray beams, the low emittance must be conserved along the beamline by choosing the best optical design. Quality of optical elements is limited by the technol. manufg. process, characterized by the values of roughness and waviness of the optical surfaces. Therefore a reliable description of an optical element is essential for having accurate results in ray-tracing simulations. A model is given for introducing the waviness effect of real optics surfaces in ray-tracing calcns. and also show some examples of simulated surfaces in comparison with real measured surfaces. [on SciFinder (R)]
Notes: CAN 117:159962 xD;73-6 xD;Optical, Electron, and Mass Spectroscopy and Other Related Properties xD;Eur. Synchrotron Radiat. Facil.,Grenoble,Fr. xD;Journal xD;0168-9002 xD;written in English.
Abstract: The need to monochromatize and focus x-rays emitted into appreciable horizontal apertures by storage ring sources (bending magnets and wigglers) leads to the design of focusing monochromators. To optimize their design, it is important to understand the combined effect of focusing and diffraction of the flux available at the sample. The combined effect of focusing and diffraction were examd. for a double-crystal monochromator which is being designed for the Superconducting Wiggler beamline (SCOW) on the ADONE storage ring in Frascati. A double-sepd. crystal system was chosen; the possibility was studied of obtaining focalization in 2 steps, by dynamically bending the crystals to obtain both tangential and sagittal focusing. Nonfocusing and semifocusing systems were also considered. The calcns. were performed with the ray tracing program SHADOW. Performances were estd. for various focusing geometries and the effect was considered of anticlastic curvature. [on SciFinder (R)]
Notes: CAN 113:87882 xD;73-11 xD;Optical, Electron, and Mass Spectroscopy and Other Related Properties xD;Inst. Cienc. Mater. Aragon,Univ. Zaragoza,Zaragoza,Spain. xD;Journal xD;0168-9002 xD;written in English.
Abstract: The effect of multiple scattering in EXAFS region for octahedral transition metal in water soln. is analyzed. A combined exptl. and theor. study is presented, in which three approxns. (Hedin-Lundqvist real and complex, and Xa) of exchange potential are used. [on SciFinder (R)]
Notes: CAN 117:159921 xD;73-6 xD;Optical, Electron, and Mass Spectroscopy and Other Related Properties xD;Fac. Cienc.,Univ. Zaragoza,Zaragoza,Spain. xD;Journal xD;1122-1437 xD;written in English. xD;7439-96-5D (Manganese); 7440-02-0D (Nickel); 7440-48-4D (Cobalt); 7440-50-8D (Copper); 7732-18-5D (Water) Role: PEP (Physical, engineering or chemical process), PRP (Properties), PROC (Process) (EXAFS of, exact spherical wave anal. of)
Abstract: The change in the electron localization and the local geometry around Ce and Fe atoms in CeRu2 and CeFe2 after the hydridation have been studied by x-ray absorption spectroscopy. EXAFS and XANES spectra of the LIII-cerium edge and the iron K-edge of CeFe2Hx (x = 0, 3.75) and CeRu2Hx (x = 0, 2.4, 3.75) are reported. Cerium atoms, which are in mixed valence state in the alloys, change their valence with the hydrogen content up to an integer 3+ value, when x = 3.75. Localization of the magnetic moment on the Ce atoms partly explains the increase of the Curie temp. in the CeFe2 hydrides and the change to an AF state in the CeRu2 hydrides. The EXAFS spectra of the hydrided compds. lack the modulating signal present in the related alloys, which implies a high local disorder around the metal. [on SciFinder (R)]
Notes: CAN 112:43051 xD;65-5 xD;General Physical Chemistry xD;Inst. Cienc. Mater. Aragon,Univ. Zaragoza,Zaragoza,Spain. xD;Journal xD;0044-3336 xD;written in English. xD;12014-50-5; 12050-64-5 Role: PRP (Properties) (hydridation of, valence change and structural local disorder induced by); 1333-74-0 (Hydrogen) Role: PRP (Properties) (in cerium-iron and cerium-ruthenium compds., valence change and structural local disorder induced by)
Abstract: The changes in the local structure and electronic configuration in CeFe2 and CeRu2 after hydridation were studied by EXAFS and XANES spectroscopies. Hydridation originate the amorphization of the Ce sublattice and the localization of the 4f electrons in Ce and 3d electrons in Fe. [on SciFinder (R)]
Notes: CAN 111:163481 xD;73-6 xD;Optical, Electron, and Mass Spectroscopy and Other Related Properties xD;Inst. Cienc. Mater. Aragon,Univ. Zaragoza,Spain. xD;Journal xD;0921-4526 xD;written in English. xD;1333-74-0 (Hydrogen) Role: PRP (Properties) (electronic configuration and local structure of cerium-iron and cerium-ruthenium contg.); 12014-50-5 (Cerium iron (CeFe2); 12050-64-5 (Cerium ruthenium (CeRu2) Role: PRP (Properties) (electronic configuration and local structure of hydrogen-contg., x-ray spectroscopy in study of); 7439-89-6 (Iron); 7440-45-1 (Cerium) Role: PRP (Properties) (spectral lines of, in x-ray spectra of cerium-ruthenium and cerium-iron contg. hydrogen)
Abstract: Exptl. and theor. evidence is presented of multiple scattering contributions in the EXAFS region for octahedral transition metal complexes. Internal collinear at. configuration, large no. of identical pathways and the c3 and c4 oscillations with nearly the same frequency are considered. The metal ion K-edge EXAFS spectra of Mn2+, Co2+, Ni2+ and Cu2+ ions in the metal chloride water solns. were measured. [on SciFinder (R)]
Notes: CAN 111:163473 xD;73-6 xD;Optical, Electron, and Mass Spectroscopy and Other Related Properties xD;Fac. Cienc.,Univ. Zaragoza,Zaragoza,Spain. xD;Journal xD;0921-4526 xD;written in English. xD;7439-96-5D (Manganese); 7440-02-0D (Nickel); 7440-48-4D (Cobalt); 7440-50-8D (Copper) Role: PEP (Physical, engineering or chemical process), PRP (Properties), PROC (Process) (EXAFS of); 14701-22-5 (Nickel(2+); 15158-11-9; 16397-91-4 (Manganese(2+); 22541-53-3 (Cobalt(2+) Role: PEP (Physical, engineering or chemical process), PRP (Properties), PROC (Process) (EXAFS of, in aq. chloride soln.)
Abstract: A new version of the popular X-ray tracing code SHADOW is presented. An important step has been made in restructuring the code following new computer engineering standards, ending with a modular Fortran 2003 structure and an application programming interface (API). The new code has been designed to be compatible with the original file-oriented SHADOW philosophy, but simplifying the compilation, installation and use. In addition, users can now become programmers using the newly designed SHADOW3 API for creating scripts, macros and programs; being able to deal with optical system optimization, image simulation, and also low transmission calculations requiring a large number of rays (>106). Plans for future development and questions on how to accomplish them are also discussed.
