This PDF file contains the front matter associated with SPIE Proceedings Volume 8139, including the Title Page, Copyright iInformation, Table of Contents, Introduction, Memoriam, and the Conference Committee listing.

Kirkpatrick-Baez (KB) mirrors consist of two individual mirrors: one vertical focusing mirror and one horizontal mirror at separate positions. Nested (Montel) KB mirrors consist of two mirrors arranged perpendicularly to each other and side-by-side. We report our results from the fabrication and tests of the first set of nested KB mirrors for a synchrotron hard x-ray micro/nano-focusing system. The elliptically shaped nested Platinum KB mirrors include two 40 mm long mirrors fabricated by depositing Platinum on Silicon substrates using the magnetron sputtering technique. Hard x-ray synchrotron tests have been performed at 15 keV and 2D focal spots of approximately 150 nm x 150 nm (FWHM) were achieved from both monochromatic and polychromatic beams at the 34 ID beamline of the Advanced Photon Source (APS) at Argonne National Laboratory. The side-by-side arrangement of nested KB mirrors requires them to have good surfaces and low figure errors at the intersection of the two mirrors' surfaces. It is very challenging to fabricate substrates that fit the nested KB mirror's arrangement and to deposit thin films to ideal elliptical shapes at the edge of the mirrors. Further research and development will be performed in the areas of fabrication and testing with respect to nested KB mirrors used in micro/nano-focusing systems. In particular, substrate processing and deposition techniques should be examined to improve the performance of the mirrors.

The design, manufacture and characterization of a Kirkpatrick-Baez (KB) configuration mirror system for high-throughput nanofocusing down to 50 nm beam sizes are described. To maximize the system aperture whilst retaining energy tunability, multilayer coated optics are used in conjunction with 2 dynamically figured mirror benders. This approach, which has been developed at the ESRF for many years, allows the focusing performance to be optimized when operating the system in the 13-25 keV photon energy range. Developments in the key technologies necessary for the production of mirror bending systems with dynamic figuring behavior close to the diffraction limit requirements are discussed. These include system optimization via finite element analysis (FEA) modeling of the mechanical behavior of the bender-mirror combination, manufacturing techniques for precisely-shaped multilayer substrates, multilayer deposition with steep lateral gradients and the stitching metrology techniques developed for the characterization and figure optimization of strongly aspherical surfaces. The mirror benders have been integrated into a compact and stable assembly designed for routine beamline operation and results of the initial performance of the system at the ESRF ID22NI endstation are presented demonstrating routine focusing of 17 keV X-rays to sub-60 nm resolution.

We investigated a one-dimensional Wolter mirror (which consists of an elliptical mirror and a hyperbolic mirror) with the aim of developing an achromatic full-field X-ray microscope with a resolution of better than 50 nm. X-ray mirrors were ultraprecisely fabricated by elastic emission machining to give a figure accuracy of 2 nm (peak-to-valley). A one-dimensional Wolter mirror that had been precisely constructed was evaluated in terms of the point-spread function at the center of the field of view (FOV) and the FOV at an X-ray energy of 11.5 keV at BL29XUL of SPring-8. It was found to have a minimum resolution of 43 nm and a FOV equivalent to 12.1 μm. These results are highly consistent with calculation results.

Bimorph mirrors are used on many synchrotron beamlines to focus or collimate light. They are highly adaptable because not only their overall figure but also their local slope errors can be corrected. However, the optimization procedure is complex. At Diamond Light Source, highly repeatable and accurate pencil beam measurements are used to determine a mirror's slope errors. These data are then used by automated scripts to calculate the necessary corrections. This procedure may be applied to any type of active mirror, but for hard X-ray mirrors, diffraction from the slits must be considered.

Realizing the experimental potential of high-brightness, next generation synchrotron and free-electron laser light sources requires the development of reflecting x-ray optics capable of wavefront preservation and high-resolution nano-focusing. At the Advanced Light Source (ALS) beamline 5.3.1, we are developing broadly applicable, high-accuracy, in situ, at-wavelength wavefront measurement techniques to surpass 100-nrad slope measurement accuracy for diffraction-limited Kirkpatrick-Baez (KB) mirrors. The at-wavelength methodology we are developing relies on a series of wavefront-sensing tests with increasing accuracy and sensitivity, including scanning-slit Hartmann tests, grating-based lateral shearing interferometry, and quantitative knife-edge testing. We describe the original experimental techniques and alignment methodology that have enabled us to optimally set a bendable KB mirror to achieve a focused, FWHM spot size of 150 nm, with 1 nm (1.24 keV) photons at 3.7 mrad numerical aperture. The predictions of wavefront measurement are confirmed by the knife-edge testing. The side-profiled elliptically bent mirror used in these one-dimensional focusing experiments was originally designed for a much different glancing angle and conjugate distances. Visible-light long-trace profilometry was used to pre-align the mirror before installation at the beamline. This work demonstrates that high-accuracy, at-wavelength wavefront-slope feedback can be used to optimize the pitch, roll, and mirror-bending forces in situ, using procedures that are deterministic and repeatable.

The B16 Test beamline at the Diamond Light Source is in user operation. It has been recently upgraded with the addition of a double multilayer monochromator (DMM), which provides further functionality and versatility to the beamline. The multilayer monochromator is equipped with two pairs of multilayer optics (Ni/B₄C and Ru/B₄C) to cover the wide photon energy range of 2 - 20 keV, with good efficiency. The DMM provides a broad bandpass / high flux operational mode for the beamline and, when used in tandem with the Si (111) double crystal monochromator, it gives a very high higher-order harmonics suppression. The design details of the DMM and the first commissioning results obtained using the DMM are presented.

The degree of coherence preservation of x-ray multilayers was investigated using Talbot imaging on the ESRF undulator beamline ID06. Several W/B₄C multilayer mirrors with differing d-spacings were studied with monochromatic light at various photon energies. To understand the respective influence of the underlying substrate and the multilayer coatings, measurements were made under total reflection, at different Bragg peaks, and on the bare substrates. In addition, samples with different substrate quality were compared. The relation between spatial coherence preservation and the visibility of characteristic line structures in the x-ray beam will be discussed.

The internal structure of Mo/Si multilayers is investigated during and after thermal annealing. Multilayer period compaction is shown to result from diffusion induced MoSi2 interlayer growth, reducing optical contrast and changing the reflected wavelength. We focus on early-stage interface growth observed at relatively low temperatures (100 °C - 300 °C), determining diffusion constants from parabolic interface growth laws. Diffusion constants obey Arrhenius-type behavior, enabling temperature scaling laws. Using the methods developed, we compare results on Mo/Si based multilayers designed for enhanced thermal stability and discuss their relevant diffusion behavior. Arrhenius-type behavior can be observed in all multilayers studied here, and demonstrates reduction of diffusion rates over several orders of magnitude. The method described here is of general interest for any multilayer application that is subjected to enhanced thermal loads and demonstrates the enormous technology gain that this type of optics has experienced the last decade.

Diffraction gratings with high efficiency and high groove density are required for EUV and soft x-ray spectroscopy techniques (such as Resonant Inelastic X-ray Scattering, RIXS) designed for state-of-the-art spectral resolution and throughput. A multilayer coated blazed grating (MBG) fabricated by deposition of a multilayer on a saw-tooth substrate could address these challenges. In order to obtain high diffraction efficiency one should provide perfect triangular grooves on a substrate and perfect replication of the groove profile during the multilayer deposition. However, multilayers trend to smooth out the corrugated surface of the substrates, resulting in the main limiting factor for efficiency of ultra-dense MBGs. Understanding of the growth of multilayers on saw-tooth substrates is a key for further grating improvement. In this work we investigate growth behavior of Al/Zr multilayers on saw-tooth substrates with a groove density of 10,000 lines/mm. We apply existing growth models to describe an evolution of Power Spectral Density functions of a grating surface during the multilayer deposition, and identify a main smoothing mechanism. We found that growth of flat multilayers is well modeled with surface diffusion caused by surface curvature as a main relaxation mechanism, while growth of the multilayer on saw-tooth substrates obeys different kinetics. Limitations of the linear approach and possible model improvements by accounting for an additional component of the surface diffusion flux, caused by a gradient of adatom concentration on a corrugated surface are discussed.

With regards to the future Laser Megajoules french facility (LMJ), our laboratory is developing advanced time-resolved High Resolution X-ray Imaging (HRXI) systems to diagnose laser produced plasma. Shrapnel and X-ray loading on this laser imposes to place any HRXI as far away from the source as possible. Grazing incidence X-ray microscopes are the best solution to overpass this limitation. These imagers combine therefore grazing X-ray microscope and camera. We designed imaging diagnostics, mainly with a long working distance (> 50 cm) and high spatial resolution. All of them are composed of single or multi-toroïdal(s) mirror(s). To increase the bandwidth of reflectivity of all these mirrors, multilayer coatings have been deposited. We present mainly microscopes using non-periodic W/SiC multilayer coatings (Supermirrors), developed in collaboration with Institut d'Optique. Supermirrors were designed for a first set of diagnostics to work at 0.7° grazing incidence. Secondly, we have implemented this supermirror on a Wolter-type microscope used at a smaller grazing incidence (0.6° angle) in order to increase the bandwidth of reflectivity up to 12 keV. Metrology for x-ray reflectance in the whole range on the synchrotron radiation facility BESSY II is also presented.

X-ray nanofocusing devices are capable of focusing X-rays down to sizes of about 10 nm. We have developed a new nanofocusing device, known as total-reflection zone plates (TRZPs), for focusing high-brilliance synchrotron radiation in the hard x-ray region. This device consists of a reflective zone pattern on a flat substrate. It has the potential to focus hard x-rays down to sub-10-nm dimensions. Furthermore, it is considerably easier to fabricate than other hard x-ray nanofocusing devices since it is used with a very small grazing incidence angle. We have focused 10-keV x-rays to sub-15 nm dimensions using a TRZP that was fabricated by conventional electron-beam lithography. In addition, we present designs for more efficient devices that have a target focus size of 5 nm. We propose and discuss a new approach for achieving point focusing with nanometer dimensions.

Recent advances in the fabrication of diffractive X-ray optics have boosted hard X-ray microscopy into spatial resolutions of 30 nm and below. Here, we demonstrate the fabrication of zone-doubled Fresnel zone plates for multi-keV photon energies (4-12 keV) with outermost zone widths down to 20 nm. However, the characterization of such elements is not straightforward using conventional methods such as knife edge scans on well-characterized test objects. To overcome this limitation, we have used ptychographic coherent diffractive imaging to characterize a 20 nm-wide X-ray focus produced by a zone-doubled Fresnel zone plate at a photon energy of 6.2 keV. An ordinary scanning transmission X-ray microscope was modified to acquire the ptychographic data from a strongly scattering test object. The ptychographic algorithms allowed for the reconstruction of the image of the test object as well as for the reconstruction of the focused hard X-ray beam waist, with high spatial resolution and dynamic range. This method yields a full description of the focusing performance of the Fresnel zone plate and we demonstrate the usefulness ptychographic coherent diffractive imaging for metrology and alignment of nanofocusing diffractive X-ray lenses.

In 1948 Kirkpatrick and Baez showed that two crossed mirrors in a tandem configuration with concave surfaces can focus hard x-rays by reflection. Right afterwards in 1949 Kirkpatrick showed theoretically that x-rays can also be focused by refraction, when they are transmitted through a similar system, i.e. in conditions, when the reflectivity at the concave interface is negligible. He performed an experiment, in which he refracted an x-ray beam at grazing incidence at such a curved interface in one direction. Consequently this was the first reported practical use of a refractive x-ray lens. The experiment was forgotten. Here we compare more systematically the focusing in such devise with the expectations. We propose the use in a flat field spectrometer, which could provide better spectral resolution for fluorescence analysis than the commonly used Si drift diodes, however, on the expense of a rather low efficiency. The application of the system may thus be limited to the spectral characterisation of x-ray sources.

BL37XU (trace element analysis beamline) and BL39XU (magnetic materials beamline) at SPring-8 have been upgraded to provide nano-probe analysis. We designed and installed Kirkpatrick-Baez (KB) mirrors and corresponding manipulators, which have an X-ray focusing beam as small as 100 nm. To realize a high-flux 100-nm focusing beam, a high-demagnification optical design was used, and new experimental hutches were constructed that are located about 80 m from the light source. By taking advantage of extended beamline, focusing photon flux density of over 1 x 10⁹(photons/sec/100x100nm²) is possible with a working distance of 100 mm at X-ray energy of around 10 keV. The current status of these beamlines is reported.

FERMI@Elettra is a Free Electron Laser (FEL) under commissioning at Sincrotrone Trieste. It will provide an almost fully coherent and transform limited radiation with a very high brilliance in the VUV/Soft X-ray range. This article describes the working principles of the Variable Line Spacing diffraction gratings applied to the photon energy spectrometer as well as the design concept, ray tracing and efficiency simulations. Metrological results at various spatial frequencies of the optics involved and the first characterization results with FEL radiation will be shown.

Material science research in the soft-X ray regime at the Swiss Light Source accommodates five beamlines where the monochromators rely on in-vacuum angular encoders for positioning mirror and gratings. Despite the factory-calibration of the quadrature signals from these rotary encoders, the energy linearization for spectroscopic data requires accurate calibration of the encoder quadrature signals. We characterize the interpolation errors and describe the Heydemann correction algorithm for the quadrature signals for improving the energy linearization on a scale comparable with the incremental encoder interpolation interval. Experimental data are shown where such errors produce sizeable effects in soft-X ray spectroscopy and for which the correction algorithm efficiently improves the short-range non-linearity.

Johansson crystals have been known for many decades as x-ray optical elements with a high resolving power and small foci. However, in the past their use in applications requiring a small focus and a narrow band pass were limited by imperfections caused by the technologies applied to their manufacture. While high performance Johansson crystals might have been achieved in some research facilities, such crystals were not commercially available. RIT has developed a process for fabricating precision Johansson crystals. The fabrication maintains the crystal structure intact. The angular precision of the bending process of atomic planes and the reflecting crystal surface is better than four arc seconds. In this paper, we will present the basic aspects of the technology and the achievements with Silicon and Germanium crystals.

Application of focusing x-ray spectrograph with spatial resolution and uniform dispersion in measurement of the imploding Al wire array z-pinch plasma is reported. Uniform dispersion (i.e., the linear dispersion is a constant, or in other words, the x-rays are dispersed on the detector with uniform spacing for every wavelength) is realized by bending the crystal of a spectrograph into a special shape. Since the spatial coordinate of the spectrum obtained by this spectrograph varies linearly with x-ray wavelength, it is very convenient for identification and processing of the experimental spectrum. The experimental results show that this spectrograph has high luminosity, high spectral and spatial resolution and is very suitable for the routine spectrum measurement on the Z-pinch facility or other high-energy-density-physics (HEDP) facilities.

Impact of Ar gas pressure (1-4 mTorr) on the growth of amorphous interlayers in Mo/Si multilayers deposited by magnetron sputtering was investigated by small-angle x-ray scattering (λ=0.154 nm) and methods of cross-sectional transmission electron microscopy. Some reduction of thickness of the amorphous inter-layers with Ar pressure increase was found, while composition of the layers was enriched with molybdenum. The interface modification resulted in raise of EUV reflectance of the Mo/Si multilayers.

X-ray flash imaging by contact microscopy with a highly intense laser-plasma x-ray source was achieved for the observation of wet biological cells. The exposure time to obtain a single x-ray image was about 600 ps as determined by the pulse duration of the driving laser pulse. The x-ray flash imaging makes it possible to capture an x-ray image of living biological cells without any artificial treatment such as staining, fixation, freezing, and so on. The biological cells were cultivated directly on the surface of the silicon nitride membranes, which are used for the x-ray microscope. Before exposing the cells to x-rays they were observed by a conventional fluorescent microscope as reference, since the fluorescent microscopes can visualize specific organelles stained with fluorescent dye. Comparing the x-ray images with the fluorescent images of the exact same cells, each cellular organelle observed in the x-ray images was identified one by one and actin filaments and mitochondria were clearly identified in the x-ray images.

An engineering prototype high average power 13.5-nm source has been shipped to semiconductor facilities to permit the commencement of high volume production at a 100 W power level in 2011. In this source, UTA (unresolved transition array) emission of highly ionized Sn is optimized for high conversion efficiency and full recovery of the injected fuel is realized through ion deflection in a magnetic field. By use of a low-density target, satellite emission is suppressed and full ionization attained with short pulse CO₂ laser irradiation. The UTA is scalable to shorter wavelengths, and Gd is shown to have similar conversion efficiency to Sn (13.5 nm) at a higher plasma temperature, with a narrow spectrum centered at 6.7 nm, where a 70% reflectivity mirror is anticipated. Optimization of short pulse CO₂ laser irradiation is studied, and further extension of the same method is discussed, to realize 100 W average power down to a wavelength of 3 nm.

Lamellar Multilayer Gratings (LMG) offer improved resolution for soft-x-ray (SXR) monochromatization, while maintaining a high reflection efficiency in comparison to conventional multilayer mirrors (MM). We previously used a Coupled-Waves Approach (CWA) to calculate SXR diffraction by LMGs and identified a single-order regime in which the incident wave only excites a single diffraction order. We showed that in this regime the angular width of the zeroth-order diffraction peak simply scales linearly with Γ (lamel-to-period ratio) without loss of peak reflectivity. However, the number of bi-layers must then be increased by a factor of 1/Γ. Optimal LMG resolution and reflectivity is obtained in this single-order regime, requiring grating periods of only a few hundred nm, lamel widths < 100nm and lamel heights > 1μm [1]. For the fabrication of LMGs with these dimensions, we use a novel process based on UV-NanoImprint Lithography (UV-NIL) and Bosch-type Deep Reactive Ion Etching (DRIE). Successful fabrication of LMGs with periods down to 200nm, line widths of 60nm and multilayer stack heights of 1μm is demonstrated. SXR reflectivity measurements were performed on these LMGs at the PTB beamline at the BESSYII synchrotron facility. The measurements demonstrate an improvement in resolution by a factor 3,5 compared to conventional MMs. Further analysis of the SXR reflectivity measurements is currently being performed.

Ultra thin gold films having a thickness of 20-30 nm are favorable laser plasma targets for a soft x-ray microscopy, because the ultra thin films emit intense soft x-rays at the wavelength of water window region from the rear side with respect to the surface irradiated with short pulse laser. Using rear side emissions, the distance between the x-ray source and the specimens can be reduced so that the x-ray flux on specimens increases. In addition, the microscope system can be designed to be compact when the specimen holder and x-ray source are combined in one piece. In the present study, the biological specimen holder combined with a gold ultra thin film plasma target has been developed for a contact-type soft x-ray microscope. This x-ray microscope system needs not any x-ray optics such as a condenser and/or an objective optics which causes a decrease in x-ray photons for imaging. Specimen holder equipped with the plasma target keeps biological specimens at wet condition in vacuum. In this study, x-ray images of hydrated living cells (MH-S mouse alveolar macrophage cell line) have been obtained successfully by use of the newly developed specimen holder. These experimental results reveal that the soft x-ray image can be taken safely. Specimen holder combined with plasma x-ray source will be a key component of a compact soft x-ray microscope using in a laboratory.

With recent advances in nanotechnology, traditionally bulky systems such as particle accelerators can be scaled down to portable sizes. Here we present a prototype micro accelerator platform which is a laser powered optical structure made of dielectric materials. As the drive laser impinges, the electric field can build up in the resonant gap between the dielectric slabs to as high as 1GV/m and electrons travelling through the gap are accelerated. Fabrication of the device involves advanced lithography, various thin film depositions, as well as fine surface finishing. In this report, we first present simulation results on the resonance and acceleration of the optical structure. Next we discuss the detailed fabrication techniques, and a prototype device will be presented. Finally, the acceleration test setup will be introduced, and some preliminary beam test results will be presented. This micro-sized structure can be used for electron acceleration and to produce X-ray radiation, in a compact device

We have demonstrated a laser-produced plasma extreme ultraviolet source operating in the 6.5-6.7 nm region based on rare-earth targets of Gd and Tb coupled with a Mo/B4C multilayer mirror. Multiply charged ions produce strong resonance emission lines, which combine to yield an intense unresolved transition array. The spectra of these resonant lines around 6.7 nm suggest that the in-band emission increases with increased plasma volume by suppressing the plasma hydrodynamic expansion loss at an electron temperature of about 50 eV, resulting in maximized emission. We also have investigated the dependence of the spectral behavior and conversion efficiencies of rare-earth plasma extreme ultraviolet sources with peak emission at 6.7 nm on laser wavelength and the initial target density. The maximum conversion efficiency was 1.3% at a laser intensity of 1.6 × 10¹² W/cm² at an operating wavelength of 1064 nm, when self-absorption was reduced by use of a low initial density target.

We characterize the emission spectra of a potassium plasma and its temporal behavior at 39 nm. To understanding the potassium spectral behavior without contamination effect, we use a laser-produced plasma to control the plasma parameters by changing the laser intensity and wavelength. Potassium ions produced strong broadband emission around 40 nm ranging from K³⁺ to K⁵⁺ ions at a time-averaged electron temperature of about 12 eV. Emission at 39 nm is caused during the recombining phase and it was reproduced by hydrodynamic simulation, which accounted for atomic processes. As the emission spectral behavior of the laser-produced potassium plasma XUV source is similar to that of the hollow cathode-mode discharge-produced plasma spectrum, it indicates that the emission from the discharge-produced plasma occurs in a region of high electron density close to 10²⁰ cm^-3.

A versatile soft x-ray flat-field grating spectrograph to be installed to a conventional transmission electron microscope has been developed. A holographic spherical grating of a 1200-lines/mm effective groove density which places emphasis on the low energy region of 50-200 eV is designed by an aspheric wavefront recording system. Laminar and blazed types master (LM and BM) gratings and their respective replica (LR and BR) gratings are fabricated by holographic exposure and ion-beam etching methods. Absolute diffraction efficiencies in the 50-300 eV range at the angle of incidence of 86.0 degrees were measured using a synchrotron radiation. The first order diffraction efficiencies are 6.1-7.5% (or 12%) for LM (or BM) and 7.4-9.6% (or 13%) for LR (or BR) gratings at near 55 eV, and over 5% (or 8%) in the 50-200 eV range for LM and LR (or BM and BR) gratings. The replica gratings show the comparable first-order diffraction efficiencies with their respective laminar and blazed types of master gratings.

Refractive x-ray lenses can be assembled from two opposing saw-tooth structures, when they are inclined with respect to each other and almost touch at one end. An incident plane wave will then traverse a varying number of triangular prisms, which direct the beam towards the optical axis and focus it. Optically speaking the plane wave traverses a parabolic lens profile, which is approximated by trapezoidal segments. The parabolic profile will focus ideally, when a lens can be discussed in the "thin lens" approximation. Now the saw-tooth refractive lens is found to be too "thick". The residual aberrations limit the focusing capability to just submicrometer focusing, significantly above the limit in diffraction limited focusing. It is shown that the aberrations can be removed by introducing a variation into the originally constant saw-tooth angle. After this modification the lens can be operated in the diffraction limited regime. Spot sizes even below 0.1 micrometer are then feasible. This performance in terms of spatial resolution is found to be limited to focusing to microspots and is not available, when the saw-tooth refractive lens is used in an imaging setup. In this case the spatial resolution deteriorates rapidly with increasing off axis distance of the object to be imaged.

The use of high quality X-ray mirrors at synchrotron beamlines as low-energy bandpass, harmonic rejection and high heat load optical elements has become routine. Nearly perfect optical surfaces generated on substrates and held in strain-free fixtures are of paramount importance to their success. Production of these mirrors requires extensive care, yet the effect of residual fabrication stress has not been closely studied. This paper examines the effect of surface and near-surface residual stress on the performance of hard X-ray mirrors using topography and X-ray reflectivity techniques. The present approach complements the information provided by standard optical metrology, giving a more comprehensive understanding of polishing induced surface deformation on X-ray reflectivity. This information is invaluable for the characterization of future, coherence preserving optics where scattering and evanescent sub-surface X-ray penetration may impact beam quality.

New physical-vapor-deposited (PVD) beryllium foils were characterized using coherent x-rays at the 1-km-long beamline in the SPring-8. Non-uniformity in the 150 μmx150 μm area is 3% (rms) for 0.1-nm x-rays and 5% for 0.15-nm x-rays which are almost similar value to that of previous PVD foils. The PVD beryllium foil has a capability for synchrotron radiation and x-ray free electron laser applications with spatially coherent x-rays.

Thermal contact in water-cooling or cryogenic cooling-cooling condition is used for forming a high-heat-load component at the synchrotron radiation beamline. In SPring-8, for example, cryogenic cooling is used for silicon monochromator crystal with an indium insertion metal at the interface between a copper block and a silicon crystal. To reduce the strain on the silicon crystal with a low contact pressure and a high thermal conductivity, we require a silicon-indium-copper system and an alternative insertion material such as a graphite foil. To measure the thermal contact conductance in a quick measurement cycle under various thermal-contact conditions, we improve the thermal-contact-conductance measurement system in terms of the setup facilitation, precise temperature measurement, and thermal insulation around a sample.

Fabrication of double-side-polished single-crystal beryllium foils for X-ray window applications were reported in an earlier paper. It was stipulated that unlike the conventional windows, polished single-crystal windows - nearly free from granular boundaries, voids, impurities, and inclusions - would essentially transmit an incident X-ray beam unaltered, except for a uniform attenuation. This paper reports on further X-ray characterization of these windows. Near- and far-field transmission images of the windows have been obtained, and the impact of the windows on the wave quality and coherence properties of the transmitted X-ray beam is demonstrated. Compared with conventional X-ray windows, single-crystal beryllium windows are shown to introduce significantly less artifacts in the transmitted beam but largely preserve coherence. The cause of sporadic and faint features in the transmitted images is discussed and wave optics computation is used to simulate some features.

We developed a non-contact method for in-situ monitoring of the thermal slumping of glass and silicone foils to optimize this technology for the production of high quality mirrors for large aperture x-ray space telescopes. The telescope's crucial part is a high throughput, heavily nested mirror array with the angular resolution better than 5 arcsec. Its construction requires precise and light-weight segmented optics with surface micro-roughness on the order of 0.1 nm. Promising materials are glass or silicon foils shaped by thermal forming. The desired parameters can be achieved only through optimizing the slumping process. We monitored the slumping by taking the snapshots of the shapes every five minutes at constant temperature and the final shapes we measured with the Taylor Hobson profilometer. The shapes were parabolic and the deviations from a circle had the peak-to-valley values of 20-30 μm. The observed hot plastic deformation of the foils was controlled by viscous flow. We calculated and plotted the relations between the middle part deflection, viscosity, and heat-treatment time. These relations have been utilized for the development of a numerical model enabling computer simulation. By the simulation, we verify the material's properties and generate new data for the thorough optimization of the slumping process.