In SPring-8, water-cooled silicon crystals are widely used for the first optical element in the x-ray undulator beamlines. This was made possible by the development of pin-post cooling combined with rotated-inclined diffraction geometry. Fabrication of the crystal uses diffusive bonding technique. Characterization at a SPring-8 undulator beamline showed high cooling efficiency enough to handle the maximum power from the undulator, although some problems still remain in fabrication process and geometrical design of water distributors.

An industrial facility for the mapping of trace impurities on the surface of 300 mm Silicon wafers will be commissioned at the end of 1998. The elements to be detected range from Na to Hg with a target routine detection limit of 10⁸ atoms/cm². The monochromator of the facility plays a central role and fulfills the following requirements: ease of operations and fast tuning (one single motor); extended energy range (1 - 40 KeV covered by a fixed exit Si(111) channel cut and multilayer pair); smooth and reliable running (water cooling even in the powerful ESRF undulator beams at high energies). The mechanical structure of the monochromator is based on well-established concepts: an external goniometer transfers the main rotation to the in-vacuum plateau via a hollow differentially pumped feed-through. The optical arrangement shows some novelties: the plateau can be cooled either by water or liquid nitrogen and it holds the convex- concave machined Si(111) channel-cut for fixed exit performances. The shape of the machined surfaces of the crystal helps also on to spread the power density of the beam on the silicon surface. A set of two identical multilayers are also mounted on the plateau and the transition from the Si(111) crystal to the multilayer operation is performed by rotating the wafer main axis by about 180 degrees. The whole facility is centered around the three main components: the monochromator, the wafer handling robots and the two linear arrays of solid state fluorescence detectors.

Simple methods for the cooling of the second crystals of cryogenically cooled undulator and wiggler double crystal monochromators are described. Copper braids between the first and second crystals are used to cool the second crystals of the double crystal monochromators. The method has proved successful for an undulator monochromator and we describe a design for a wiggler monochromator.

A set of internally water-cooled multilayers were fabricated for the double crystal monochromator of the A2 wiggler beamline at CHESS. With over 3 kW total deposited on the first multilayer, conventional contact cooled multilayers proved unable to cope with the incident heat load. Cooled silicon substrates were fabricated with internal water cooling channels to reduce or eliminate thermal distortion. The highly polished top surfaces were coated with a sputtered W/C or W/B₄C multilayer film deposited at the Advanced Photon Source and Osmic, Inc. respectively. Measured reflectivities over 60% and bandwidths of 1.3 - 1.8% were obtained. Results to beam currents of 250 mA show the effectiveness of the internal cooling design and have provided x-ray fluxes of 1 X 10¹³ photons/sec/mm².

A double bounce monochromator with a roughened Si(111) first crystal and a sagitally focusing roughened Si(111) second crystal was tested at a Cornell High Energy Synchrotron Source (CHESS) bending magnet line. Flux and energy width measurements were taken and comparisons are made with measurements from a perfect Si(111) monochromator (also sagitally focused) as well as calculations for flux and energy width for a source-matched monochromator and a mosaic monochromator. For the roughened monochromator at 17 keV, the flux was greater by a factor of 7.5 while the energy spread was only increased by a factor of 2, as compared to the perfect monochromator. These measured increases are consistent with predicted values for source-matched optics. Other advantages of mosaic monochromators in addition to source- matching are discussed.

The physical properties of diamond represent in very many cases an extreme. Consequently it is predicted that diamond may be an excellent material to use in many applications. One of these is in intense X-ray fluxes such as produced by modern synchrotron sources. In this paper the implications in deploying diamond for such purposes are addressed. This includes a consideration of the nature of natural diamond, and in particular its characteristic defects. Progress in attempts to emulate Nature in diamond genesis makes available to us man-made diamond produced at high temperature and high pressure: such material is considered as an alternative to the natural form for diamond targets. In recent times man-made diamond has been produced by chemical vapor deposition: the characteristics of this type of diamond are identified. In regard to the preparation of the actual target, three areas are considered, the 'thick' diamond target, the 'thin' diamond target, and the 'composite' diamond target. Traditional methods are described for the preparation of thick diamonds, while new approach based on amorphizing layer of diamond in the prepared stone at a predetermined depth, which can be etched away releasing the superficial layer of undamaged diamond. Some applications of diamond targets are presented.

In an effort to provide synchrotron x-ray beamlines with improved monochromators, a new series of 111-oriented diamond crystals up to 50 mm² large with thicknesses ranging from 67 micrometer to 175 micrometer was prepared, tested and found to be of very high quality. One sample appeared to be without any defects. Some linear defects were observed by topography on the other samples but without any consequences for the rocking curve width, except for one sample that revealed some mosaicity in part of its volume and could serve as variable flux/resolution monochromator. The rocking curve width exceeded sometimes the theoretical perfect crystal value by a couple of arcsec. Peak and integrated reflectivities were observed to be very close to the theoretical values for a perfect diamond crystal. For the first time, a diamond crystal was elastically bent to achieve sagittal focusing. Although the bending was not absolutely uniform, a spot size of 1 micrometer and gain factors exceeding one order of magnitude were obtained. These results showed that dispersion-free diamond double crystal monochromators of the classical type can be made.

We report on the use of Na-(beta) alumina crystals in a synchrotron soft x-ray monochromator. With a grating spacing of 22.53 A, Na-(beta) alumina allows coverage of the .6 - 2 keV energy region not available to high resolution Si or Ge crystals. The crystal is shown to have an intrinsic energy resolving power E/(Delta) E of 800 - 1300 in first order with relatively high throughput. Second order (2d equals 11.26 A) is also strong, with a potential resolving power E/(Delta) E of 5000. The refractory nature of the crystal allows it to survive synchrotron heat loading without the damage experienced by organic long grating spacing crystals. The crystal is readily cleaved simplifying fabrication, alignment and mounting. Drawbacks include strong second order harmonics and strong anomalous dispersion effects from Na and Al.

We present investigations of bendable comb-shaped Si crystals and Si_1-xGe_x gradient crystals, tested in Laue geometry, to be used as monochromator and analyzer for triple crystal x-ray diffractometry with high (around 100 keV) energy synchrotron radiation. At these energies, both the high q- space resolution of synchrotron radiation and the high penetration power of neutrons are present. The overall resolution element in q-space is usually dominated by the properties of the sample. A comb crystal structure can provide a gain in integrated intensity of up to a factor of 70, compared to perfect Si crystal monochromator and analyzer, by adjusting the instrumental resolution to the needs of a sample. However, this intensity gain can further be increased by using Si_1-xGe_x gradient crystals. The continuously- changing lattice parameter in these crystals yields an increase in maximum peak reflectivity of up to 100% in comparison to theoretical limit of 50% for normal crystals in Laue geometry. Recently good Si_1-xGe_x gradient crystals of sufficiently large size have been grown by means of the Czochralski technique with geranium content x between 0.02 and 0.08. We find peak reflectivities of these crystals of up to 96%, accompanied by a large increase of the FWHM of the reflection. Combining these properties and the principle of the comb structure, the intensity gain should be easily increasable to factor of 1600 as compared to a set-up with perfect single-crystal monochromator and analyzer.

We describe a novel coolant suitable for high heat load optics called Binary-Ice^R. This coolant exploits the latent heat of microscopic ice particles in a water/antifreeze mixture, which confer an effective specific heat capacity up to eight times that of water. Binary-Ice^R has a film heat transfer coefficient several times that of water or brine which reduces the thermally induced strain in optical components compared to identical water-cooled configurations. Furthermore, the coolant temperature only increases by a few degrees under normal operating conditions, yielding uniform cooling. Finite element analysis has been used to model a thin silicon [111] crystal that is back-cooled by brine or Binary- Ice^R with an incident power density of 4 Wmm^-2 commensurate with a modern bending magnet monochromator. Water cooling was found to be impracticable due to the thermal bump inducing a spread in the selected bandwidth which was greater than 50% worse than the intrinsic resolution of Si[111], and a downward shift in the energy by more than the intrinsic bandwidth. By comparison Binary-Ice^R yielded the intrinsic resolution at low energies and a shift in the energy by only 10% of the bandwidth. The application of Binary-Ice^R for cooling of diamonds in undulator monochromators, and for the cooling of x-ray mirrors and multilayers is also discussed.

High resolution X-ray topography and diffraction measurements have been made at the Daresbury Synchrotron Radiation Source during in-situ molecular beam epitaxial growth of InGaAs on GaAs. Critical analysis of dislocation contrast, intensity and geometrical distortion reveals that use of the 224 reflection in the Bragg geometry at 1.48 Angstrom wavelength is optimal for such double crystal topography experiments. Examination of the beam-conditioner characteristics and performance had resulted in use of the 333 reflection from a channel-cut silicon crystal as a monochromator. We deduce and show experimentally that a 004 channel-cut monochromator is optimal, resulting in significant reduction in exposure times. We present images of misfit dislocations showing evidence for the first time of phase contrast from lattice distortions.

On a beam line of a third generation synchrotron facility, such as the ESRF, the small source size of the source and the large distance from the source to the sample are responsible for the remarkable coherence properties of the beam at the sample position. In Bragg diffraction by a perfect crystal, the incident beam is to be considered as a coherent spherical wave, with angular aperture larger than the angular reflection range of the crystal. We show theoretically that, in such condition, the intensity profile of a Bragg diffraction topograph, in transmission geometry (Laue case), should reproduce the angular Bragg reflection profile (rocking curve) of the crystal. We discuss the conditions to be fulfilled concerning the wavelength dispersion of the incident beam. An experimental verification of the theoretical prediction is presented.

It is shown that high-resolution x-ray diffraction analyses on coherent thin-film microstructures on crystal surfaces can reveal a variety of information on interfacial strain fields. Diffraction features that can be observed include diffuse interference fringes, asymmetric grating diffraction patterns, and asymmetric crystal-truncation-rod profiles due to the strain-varying regions in a microstructure. From these diffraction features, both the longitudinal and the transverse strain gradients can be determined, in addition to the average elastic strain-tensor components.

The advantage of using high-resolution powder diffraction data to resolve ambiguities in powder diffraction analyses is widely understood. The problem with using such an instrument for routine analyses is the length of time needed to acquire a data set. An obvious solution is to introduce some parallelism in the detector/analyzer system. The system described here uses monolithic elastic design principles to construct a simple 16-element crystal analyzer, and it uses silicon multi-detector technology developed at Brookhaven to provide a compact 16-channel pulse-counting detector system. Together these components can decrease the data collection time by at least a factor of 10. Simple replication of components could further increase the efficiency of collection.

The use of high energy synchrotron radiation (above 80 keV) for diffraction experiments offers many advantages resulting from the high penetration depth of the high energy photons and the small Bragg angles. The main features are: the possibility for the study of large sample crystals in transmission geometry, simple sample environments, high instrumental resolution in reciprocal space, the ability to utilize high momentum transfers and small correction factors for scattered intensities. The experiments performed at this kind of diffractometer are driven by the photon flux, in which the only requirement is a relatively small angular divergence for the incident beam in the scattering plane. The new triple crystal diffractometer introduced here will be installed at the elliptical multipole wiggler beamline at the Advanced Photon Source (APS). Because of the high critical energy of this device, 32 keV, the wiggler will produce high intensities at very high photon energies. To collect up to 1 mrad of the horizontal divergence of the beam, a bent annealed silicon monochromator will scatter and focus in the horizontal scattering plane. The diffractometer will be operated in the vertical scattering plane taking advantage of the small vertical beam divergence.

Different types of crystal bending devices have been developed at the ESRF in the past few years for sagittal focusing of relatively wide bending magnet and wiggler synchrotron x-ray beams and of more tightly collimated undulator radiation. Their basic features and performances are presented, together with practical experience. A new bender for dynamical microfocusing of undulator beams down to micrometer spatial resolution with high efficiency is described.

We present the design and test of a sagittally focusing crystal monochromator for the protein crystallography beamline of the Swiss Light Source (SLS) and discuss the limiting factors in sagittal micro-focusing of undulator radiation. The monochromator concept combines flexibility with stability and reproducibility, in particular for Multiple-wavelength Anomalous Dispersion (MAD) experiments. Together with a dynamically bent, vertically focusing mirror, it will accept the full central cone from the undulator and deliver a fixed- exit beam with adjustable focus size between 20 and 200 micrometer in the energy range of 7 - 17.5 keV. The characteristic feature of the crystal is a double step connecting the inner bent region with the outer stiff part. The crystal rests on one step (neutral layer) and by the other is kept in position relative to the bender without application of forces, thereby minimizing crystal deformations and alignment errors. Cylindrical bending is achieved by means of four motorized micrometer-screws which act directly on the stiff parts of the crystal. The bender was tested at ESRF and a beam of 6 X 1 mm² was focused to 20 micrometer at 10 keV. The efficiency was close to 90%. Dynamical focusing was demonstrated. Residual bending errors could be traced back to thickness variations of the bent crystal part.

Three different ways of creating a broad energy band X-ray beam have been tested for studying electric field induced changes in Bragg intensities. The basic idea behind all three techniques (graded multi-layer, bent Laue crystal and filtered white beam) is to try to separate the change in integrated intensity on one side from changes in peak shape and peak position on the other side. All three techniques give a significant increase in data collection speed, as compared to the more standard highly monochromatic method. However, only in the case of bent Laue crystal monochromators could the energy spectrum be made sufficiently flat to give a complete separation of the effects related to structural changes from the effects related to peak shifts and peak deformations.

A fixed-exit monochromator, which requires only a single rotation, is described. It is based on a Si-111 crystal which has profiled reflecting surfaces and an undistorted lattice. The purpose of the surface profile is to keep the beam exit fixed, while the monochromator needs only a rotational movement. The monochromator must have a negligible effect on the phase space of the outgoing beam, to avoid astigmatic errors when microfocusing the monochromatic beam. The influence of the crystal on the phase space has been calculated to confirm that it is compatible with the production of a microspot of about 20 micrometer diameter using subsequent focusing optics, which is a basic requirement for the object illumination in the imaging type X-ray microscope at the experimental station.The performance of the monochromator in terms of bandwidth, throughput and stability of the beam position has been calculated and measured. Limitations in terms of energy range and acceptable thermal load are discussed.

ID14/Quadriga at the ESRF is an undulator beamline dedicated to monochromatic macromolecular crystallography. Based on the Troika concept, this beamline has four simultaneously operating experimental stations: three side stations using thin diamond crystals, and an end station with a fast-scan double-crystal monochromator and a toroidal mirror. Two undulators with 23 mm and 42 mm periods and a minimum gap of 16 mm on a high-beta section provide a high brilliance X-ray beam between 6.2 keV and 35 keV. The principle of a multiple station beamline on an undulator X-ray source has been developed by Als-Nielsen. We use the (111) reflection of an (100) oriented diamond in asymmetric Laue mode or a (111) oriented diamond in Bragg mode in order to select a wavelength for the side station. Compared to the Troika beamline at ESRF, the optical system is more complex comprising a sagitally (vertically) focusing Ge(220) crystal and a multilayer on a bimorph bender for horizontal focusing. Independent focusing in the horizontal and vertical planes allows the use of both a Bragg-Bragg setup of the monochromator and a Laue-Bragg setup where difficulties arise from energy dispersion and focusing effects of the Laue crystal. The properties of a thin diamond crystal in asymmetric Laue mode are discussed. The optical system provides a high brilliance monochromatic X-ray beam with focal spotsize down to 0.2*0.06 mm² FWHM and a flux of about 1*10¹¹ photons/s at 13.2 keV. The opticl system of the first side branch, Quadriga-3, is operating since summer 1997.

A newly designed multi-crystal X-ray spectrometer and its applications in the fields of X-ray fluorescence and X-ray Raman spectroscopy are described. The instrument is based on 8 spherically curved Si crystals, each with a 3.5 inch diameter form bent to a radius of 86 cm. The crystals are individually aligned in the Rowland geometry capturing a total solid angle of 0.07 sr. The array is arranged in a way that energy scans can be performed by moving the whole instrument, rather than scanning each crystal by itself. At angles close to back scattering the energy resolution is between 0.3 and 1 eV depending on the beam dimensions at the sample. The instrument is mainly designed for X-ray absorption and fluorescence spectroscopy of transition metals in dilute systems such as metalloproteins. First results of the Mn K(beta) (3p yields 1 s) emission in photosystem II are shown. An independent application of the instrument is the technique of X-ray Raman spectroscopy which can address problems similar to those in traditional soft X-ray absorption spectroscopies, and initial results are presented.

A new type of x-ray focusing crystal diffractor based on a pseudo-spherical stepped geometry is presented. This device is a particular stepped surface, where each element is a spherically bent rectangular crystal, whose reflecting planes are parallel to the surface and oriented so as to fulfill the Bragg condition. The area of each surface element (step) is chosen such as to define the same solid angle. Theoretical parameters and performances of a high resolution Multi-Stepped Monochromator (MSM) based on this geometry are estimated for some typical applications. To this aim, an original approach that allows to determine the Bragg reflection area of each element has been developed and applied both to spherical and pseudo-spherical diffractors. The calculations indicate that the gain of the proposed optical design is significantly enhanced as compared to the best crystal devices bi- dimensionally focusing. In particular in the high resolution conditions, the gain in spectral throughput of a MSM device is about one order of magnitude, with respect a conventional one.

We discuss the possibilities for using Kirkpatrick-Baez (K-B) multilayer elements to directly image the fluorescence distribution from a specimen under x-ray illumination. X-ray fluorescence would be collected by K-B elements close to the specimen, with a magnified image formed at an area detector about 0.5 m away from the source. This is in contrast to the use of K-B optics to form a microprobe beam that is rastered across a surface while the x-ray fluorescence is recorded to form a fluorescent image. Tungsten-carbon multilayers on curved substrates have been fabricated at the Advanced Photon Source, and their focusing properties have been characterized by a laboratory x-ray source. Synchrotron applications would illuminate specimens with lithographic patterns, for example, with the image being formed at an x-ray CCD camera. The ability to form an x-ray fluorescent image, and therefore a map of the specimen's elemental distribution near the surface, could provide a useful analytical tool without the usual need for a microfocusing beam. Furthermore, there are interesting possibilities offered by combining fluorescence imaging with x-ray near edge absorption spectroscopy (XANES), extended x- ray absorption spectroscopy (EXAFS), and x-ray standing waves.

Our goal was to prepare an X-ray Fluorescence Holography (XFH) experiment at ESRF, in which the holographic information is approximately 0.3% of the overall isotropic fluorescent radiation. This requires a very pure fluorescent signal and the highest possible count rate. Therefore, we designed a focusing analyzer system with large solid angle acceptance. It consists of a sagittally bent pyrolithic graphite crystals with large solid angle acceptance used in the parafocusing mode for the meridional plane. We successfully applied it to collect a large fraction of isotropically emitted Fe, Ni and Pd K_(alpha ) fluorescent photons with the [002] and [006] graphite reflections, respectively. After characterizing the phase space efficiency (angular acceptance, focal spot shape) of a 200 mm long, doubly focusing analyzer, we developed a full circular one (220 mm diameter) to increase the solid angle acceptance to approximately 2 10^-2 sr, in view of an XFH experiment on MBE grown thin films. This analyzer can be used more generally at K and L edges for atoms with Z greater than or equal to 20.

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.

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.

The high-brilliance radiation provided by third-generation synchrotron x-ray facilities such as the Advanced Photon Source has greatly enhanced the power of such chemical and materials research techniques as x-ray-absorption spectroscopy, surface scattering, small-angle x-ray scattering, and chemical crystallography. In order to take full advantage of these source properties, we propose the development of a general-purpose high-energy-resolution double-channel-cut monochromator based on a similar device developed for nuclear-resonant-scattering techniques by the Experimental Facilities Division at the APS. The instrumentation will be installed at the APS on the ChemMatCARS insertion-device beamline at sector 15. It will be used primarily for valence-specific static and time-resolved chemical-crystallography experiments as well as anomalous- scattering experiments planned for surface diffraction and small-angle/wide-angle x-ray scattering. Two channel-cut crystals placed in a dispersive (-n, +n, +n, -n) geometry provide a fixed-offset beam with an energy resolution (Delta) E/E approximately 10^-5. Several sets of channel-cut-crystal pairs, designed to cover an energy range from 6 to 35 keV with a matching angular acceptance to the source, are used in conjunction with the beamline high- heat-load double-crystal monochromator.

Third generation synchrotron light sources present new challenges to x-ray optics calculations. Due to the high brilliance (thus small dimensions) of the source and the long optical paths, the transverse coherence lengths are quite nonnegligible, often of order of hundreds of microns. In such situation beam propagation calculations based on purely geometrical optics may yield large errors and a more complete wave treatment is needed. This is especially true for beam defining apertures. The purpose of this paper is to present a calculational approach which, utilizing a 'variance matrix' representation of the beam allows to evaluate the wave propagation along an optical system and through arbitrary apertures, in a straightforward manner. In addition the notoriously thorny problem of partial coherence is adequately dealt with and the transition from wave optics to ray optics obtains in a smooth and seamless fashion.

High reflectance multilayer films can now be deposited onto figured substrate to make focusing X-ray mirrors. In this paper, I discuss a variety of topics associated with the development and further refinement of such X-ray optics: high- efficiency multilayer films for use near normal incidence in the 170 - 300 Angstrom region; depth-graded multilayer films for broad-band reflectance in the 10 - 100 keV region; surface roughness and it's effect on mirror performance; and finally stresses in multilayer films.

X-ray scattering measurements at 10 keV from multilayers having a period of 24.8 Angstrom and consisting of 100 W/C bilayers are reported. Specular scans revealed first order reflectivities in the range 73.5% to 78.0% with bandpasses in the range of 1.5% to 1.7%. Total roughness (or interface grading) values deduced from fitting were in the range 2.5 to 3.0 angstrom for the last-to-grow surface of the W layers. Diffuse scattering measurements were made in a novel geometry that permitted investigation of in-plane momentum transfers up to 0.2 Angstrom^-1. This is roughly an order of magnitude larger than is possible in conventional rocking scans. A power law dependence of the diffuse scattering after integration over a 'Brillioun zone' is found. The exponent of this power law, 1.75, when interpreted using a logarithmic correlation function leads to a value of 1.0 angstrom for the correlated roughness.

Grazing incidence specular reflectance and near specular scattering of uncoated and multilayer coated substrates are measured at Al-K(alpha) (1.486 keV) and Cu-K(alpha) (8.047 keV). Substrates included superpolished fused silica, SiO₂ wafer, superpolished and precision ground Zerodur, float polished BK7 glass, and precision ground silicon carbide. Surface topography of these substrate had been measured with the Scanning Probe Microscope (SPM) and a Talystep mechanical profiler. The results showed that roughnesses obtained from 100 micrometer X 100 micrometer SPM images and 100 micrometer Talystep profiles were in good agreement with that calculated from the Al-K(alpha) X-ray measurements. X-ray measurements of the multilayers deposited on these substrates are very important. The results of this study can be used as a foundation of calculating the X-ray specular reflectance and diffuse scattering at grazing incidence from multilayer coated mirrors. We coated these substrates with Pt/C multilayers. Its periodical length were 40 angstrom and number of layer pairs was 40. The measured reflectivity showed no significant correlation between interfacial roughness of multilayers and the substrate surface roughness. The interfacial roughness of most samples scattered around 3 - 4 angstrom except for the precision ground silicon carbide and the precision ground Zerodur. The surface roughness of these exceptional substrates are considerably larger value of 6 angstrom and 9 angstrom rms from Talystep measurement. When the surface roughness of the substrate is small enough, typically less than 3 angstrom interfacial roughness of multilayers are considered to be independent from substrates.

In order to investigate the technical feasibility of X-ray optical devises in the XANES energy region, we used typical carbon compounds with (pi) * molecular orbitals i.e. C₆₀, C₇₀, carbon nanotube and graphite. Their real and imaginary parts of the optical constants were studied. In this study, using XANES observation spectrum data and calculations by the Hartree-Slater method, the atomic-scattering factors of compounds near carbon K-edge region were obtained. It was found that outstanding anomalous dispersions are observed in the near carbon K-edge region; and it was also found that the compounds have peculiar and complicated optical properties due to the chemical-bond structures. Furthermore, based on the obtained results, we designed a metal/graphite normal-incident X-ray multilayer in the region and also considered its application to an X-ray microscopy.

Recent progress in the manufacturing of X-ray multilayers has opened up new possibilities in the field of hard x-ray optics allowing to produce wide bandpass optical elements through the design of depth-graded multilayer coatings. However, the inverse problem consisting of inferring the composition profile of the multilayer has only been addressed in a semi- empirical way, which encouraged us to develop a new (theoretical) approach. Our method is composed of three steps. First, we use an approximate analytical expression to describe the x-ray reflectivity spectral dependence of any arbitrary graded-multilayer structure. Such an approximation is obtained by assuming the multilayer d-spacing profile to be a monotone function of the depth. The d-spacing gradient is also assumed to be large enough, so that the reflection condition for each given energy is fulfilled in a depth zone that is small compared to the thickness of the multilayer stack. On this basis we could derive the differential equation that describes the change of period necessary to guarantee a given spectral reflectivity profile. Then, a computer code, written for solving the inverse problem, lead us to the desired multilayer period profile. Finally, the effective spectral dependence of reflectivity was accurately computed using a standard matrix method. Simulations of the particular case of constant reflectivity over a wide spectral range are presented. Possible applications of wide bandpass multilayers in synchrotron and astrophysics hard x-ray optics are discussed.

We present the recent advances achieved in the Changchun Institute of Optics and Fine Mechanics, Chinese Academy of Science, in the field of the soft X-ray etched multilayer optics. In the present study, Mo and Si have been chosen as materials for the scattering layer and space layer soft X-ray multilayer, respectively. The fabrication of Mo/Si multilayer used by the magnetron sputtering, the patterned resist was obtained by optical holography, and the pattern of the resist was transferred into the multilayer by the ion beam etching. The several components based on soft X-ray etched multilayer were measured by grazing incidence X-ray reflectance measurements at (lambda) equals 0.154 nm (Cu-K_(alpha )) using a conventional diffractometer.

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.

Three water-cooled pin-post monochromators, to be used on a wiggler beamline at the Advanced Photon Source (APS), were built with the heat exchanger engineered to provide very high heat transfer. The geometry of the heat exchanger as well as calculated data on the heat transfer will be presented. Before using the monochromators on the beamline, they were checked by x-ray diffraction topography. Reflections (333) and (220) in Bragg case were utilized. In all crystals, similar patterns of strain in the diffracting silicon layers were revealed, which can be attributed to the geometry of the heat exchangers, the bonding technology, and the thickness of the top layer. Conclusions about construction of future pin-post monochromators have been drawn.

For powder diffraction, high resolution can be best achieved using the parallel beam geometry with a monochromator/analyzer combination. However experiments are long and a way to reduce this time without compromising resolution is to use several analyzer/ detector combinations mounted on a single (theta) _a/2(theta) _a goniometer. We have developed such a solution for the 'Powder Diffraction' BM16-ESRF beam line. This device comprises nine analyzer/detectors, with a fixed prealigned offset of two degrees between adjacent analyzer crystals, and can be used in the whole energy range of the powder diffraction instrument (from 6 to 40 keV). The only required adjustment is the classical (theta) _a/2(theta) _a rotation of the supporting goniometer when the wavelength is changed. Moreover, the detector array can be used in the Debye Scherrer geometry without dismounting the multi-analyzer stage, only by positioning the goniometer at an ad-hoc (theta) _a/2(theta) _a angle, and inserting slits in front of the detectors. This multi-analyzer system is mainly dedicated to high resolution experiments and a peak width (FWHM) of 0.006 degrees in 2(Theta) has been achieved with a Si(111) monochromator on the BM16 ESRF beam line. Since the prealigned offset is small (2 degrees), the measuring time can be considerably reduced even for scans of small angular ranges, for high energy experiments or for high resolution in-situ studies. This set-up has also been used for anomalous diffraction studies and experiments on amorphous compounds, where it provides efficient elimination of fluorescence scattering and background from ancillary equipment. This system is in operation on the ESRF powder diffraction BM16 beam line since 1996 and has been extensively used for more than 90% of the beam time.

With the aim to improve the reliability of calculating and thus predicting the thermal deformation of cryogenically cooled silicon monochromators for intense synchrotron x-ray beams, we have measured the thermal conductivity of several specimen with different purities: float zone (FZ), Czochralski (CZ) single crystal materials and a Si_99.3Ge_0.7 (SG) crystal between 85 K and room temperature with 1% accuracy. We have shown by finite element analysis that a measured 30% increase of conductivity between the FZ and the CZ crystals leads to an increase of 30 to 40% of the thermal slope. Whereas the performances of these two materials were just acceptable, the 9 times reduced thermal conductivity of the SG crystal turned out to increase the thermal slope error by a factor 19 to a prohibitive value of 143 (mu) rad, as compared to 7.6 (mu) rad for the FZ crystal. Therefore, the application of SG crystals to cryogenic cooling cannot be recommended. In addition, we determined the thermal conductivity of germanium single crystals in the same temperature range. For the silicon FZ and the germanium materials, excellent agreement with recommended values was found. Moreover, we detected a small, but non-negligible dependence of thermal conductivity on the crystallographic direction (a few % at 85 K) that, to our knowledge, has not been published in previous papers.