This PDF file contains the front matter associated with SPIE Proceedings Volume 11837 including the Title Page, Copyright information, and Table of Contents.

The optical system consisting of X-ray refractive axicon lenses and traditional parabolic lenses is considered. Such lenses combination makes it possible to flexibly adjust the size of the focused ring-shaped beam produced by axicons changing their number in the optical system. It was theoretically shown that the considered lens system is analogous to the X-ray refractive parabolic axicon. The axicons were made from polycrystalline aluminum by a pressing technique. The optical properties of the presented beam-shaping lens have been experimentally tested at the European Synchrotron Radiation Facility (ESRF). The obtained results are fully consistent with theoretical calculations. Additionally, the numerical experiment was carried out to demonstrate the influence of the axial symmetry of the optical scheme as a whole and axicons conical shape distortion on the focused annular beam. Future possible applications of the axicon are discussed.

The study of the applicability of a nano-polycrystalline diamond (NPD) as a lens material is presented. Two NPD plates with a diameter of 8 mm and a thickness of 0.1 and 1 mm were manufactured using the HPHT process. Coherence preservation properties of the NPD samples were checked using in-line phase-contrast imaging. Wide-Angle X-ray Scattering and Small Angle X-ray Scattering experiments were performed to examine the NPD scattering properties. Rotationally parabolic half-lens from a 100 μm thick NPD plate was manufactured using the maskless direct milling using a Zeiss CrossBeam 540 FIB-SEM system.

The X-ray planar compound refractive lenses (CRLs) made of monocrystalline silicon by a lithography and plasma deep Si etching (Bosch process) were considered. The CRL is a planar structure of biconcave parabolic refractive surfaces etched into silicon wafers down to 70 μm. The geometrical parameters of the parabolic lens structures were measured by different SEM-based methods and compared with CAD data. The influence of the manufacturing errors on the CRLs optical properties was discussed. The approaches for the improvement of the lens manufacturing techniques were proposed.

Due to its outstanding thermal properties and low x-ray loss diamond had been considered a material for x-ray refractive optics for a long time. Several diamond lens prototypes had been produced by various groups and tested at different light sources. However a commercial grade diamond lens is not yet on the market. Because of the large number of complex fabrication steps involved (packaging, laser ablation, polishing and metrology) combined with stringent accuracy requirements (1 micron standard deviation from the designed paraboloid shape) diamond lenses are not consistent from one to another. In this paper we will review the recent progress in lens development and share results demonstrating that a beamline-ready diamond refractive lens is now available.

Diamond has low x-ray absorption relative to refractive strength and outstanding thermal properties, making it well-suited for refractive optics for high-power (white beam) and monochromatic synchrotron x-rays. In addition, single-crystal diamond offers the advantage of preserving beam coherence, exploiting that property of high-brilliance and ultra-low emittance new sources such as the multi-bend-achromat upgrade of the Advanced Photon Source (APS). The small curvature-radius, bi-concave, diamond compound refractive lenses (CRLs) presented here were fabricated by femtosecond-laser ablation followed by optional polishing. Focusing tests were conducted with high-energy x-rays (~50 keV) in a long focal length configuration at the APS 1-ID beamline. A convex CRL for beam expansion is also presented.

In the soft x-ray region, the demand for focusing x-rays into a spot of nanometer order size with high efficiency has been increasing. Ellipsoidal and Wolter mirrors, which are representative of ideal reflective focusing optics for soft x-rays, have optical advantages such as achromaticity, large acceptance, high efficiency and high numerical aperture, which are suitable to fully utilize the next-generation synchrotron light sources. Recently, the fabrication process of soft x-ray mirrors of replication type using nickel electroforming was developed, and several focusing experiments with ellipsoidal and Wolter mirrors were reported. The experimental environment of these mirrors, however, was limited due to the magnetism of the nickel body. We are currently developing the diamagnetic mirror fabrication process using copper electroforming technique to expand its application. In order to prevent oxidization of the replicated surface, this study demonstrates electroforming of copper mirror that has the reflective surface of gold. The surface roughness replicated from a flat substrate was 0.321 nm in root-mean-square in 0.1 mm × 0.1 mm area. The circularity of the gold inner surface of a copper electroformed mirror was evaluated at 26 nm in peak-to-valley.

PZT (lead zirconate titanate)-glued bimorph deformable mirrors are widely used in hard x-ray regimes[1], however, they have not yet been used in soft X-ray regimes because they are less compatible for usage under high vacuum. Therefore, we have developed a glue-free bimorph deformable mirror, in which silver nanoparticles were employed to bond PZT actuators to mirror substrates[2]. In this study, we achieved a 2 nm figure error on an elliptical shape of a glue-free deformable mirror. We evaluated the figure change characteristics due to humidity and temperature increasing at the ultrafine figure error condition.

Axisymmetric mirrors, such as ellipsoidal mirrors, are used as nanoscale focusing elements for soft X-rays. High figure accuracy is required to prevent distortion of the wavefronts of reflected X-ray beams. Although a mirror fabrication technique based on electroforming has been developed, figure correction of the inner surface of the mirror with most of the conventional machining methods is difficult. In this study, we constructed a processing system specialized for the inner surface of axisymmetric mirrors. This system is based on a fluid jet processing method. A fluid containing abrasives flows out from a very small nozzle placed inside the mirror and impinges against its inner surface. The surface layer of the mirror is locally removed with a spatial resolution of about 2 mm using this system. Abrasives used in our system contain organic resin and silica; therefore, they have a sufficient machining rate and a good dispersibility in water. We also applied X-ray ptychography to measure the 3-dimensional figure error of the mirror surface. We performed numerically controlled processing and measured the surface figure of the mirror with both a contact-type roundness measurement machine and a soft X-ray ptychographic system. The result of X-ray ptychography agreed well with the profile obtained by contact measurement.

An upgrade of the IIT bending magnet beamline (10-BM) at Argonne National Laboratory is described. The goal is to provide a higher photon flux, approaching the theoretical limits, by incorporating focusing mirrors. This would allow faster in situ x-ray absorption spectroscopy measurements in the 5-30 keV photon energy range with higher spectral resolution. This upgrade is accomplished by incorporating a pair of focusing mirrors such that the current beamline layout and experimental hutches are preserved. The first mirror, upstream of the monochromator system, collimates the beam vertically to increase the monochromator throughput. The second mirror, downstream of the monochromator, focuses the resulting monochromatic beam in both the horizontal and vertical directions. Toroidal, bent cone, and diaboloid mirror profiles are compared. It is shown that a diaboloid mirror provides the best option given the beamline physical constraints. Challenges in the fabrication of this mirror are discussed. The complications due to the strong absorption edges of the mirror surface are mitigated by a tri-layer coating of Sb/Pt/Cr over the entire mirror surface. Simulation results show that the coated diaboloid mirror would focus the beam with minimal aberrations and provide an approximately 300-fold increase in flux onto a 0.2 x 0.2 mm2 aperture at 30 m from the source.

We have developed an X-ray zoom condenser optical system using deformable mirrors that can adjust the beam size by deformation of their shape. The shapes of deformable mirrors are changed by a combination of mechanical and piezoelectric bending. Large deformations up to third order polynomials are achieved by mechanical bending. More precise shapes are achieved by piezoelectric bimorph mirror. However, because both ends of the mirror are mechanically clamped, capability of deformation by piezoelectric bending is lower than that of free-standing piezoelectric bimorph mirrors. So, we propose a bending method that tunes the mechanical bending conditions to intentionally leave the optimized shape error to be easily compensated by the piezoelectric bending process.

The figure errors of an x-ray mirror were reduced by differential deposition of C/Pt layered structures. Different apertures were inserted into the particle beam to correct height errors on variable length scales down to less than 10 mm. The required velocity profile was calculated using a deconvolution algorithm. The film thickness profiles were measured directly by xray reflectivity. Height errors were evaluated using visible light surface metrology. The results of these different techniques are compared and discussed. After two iterations the shape error of a 300 mm long flat Si mirror was reduced by a factor of 5 to less than 1 nm RMS. This work describes the experimental techniques and discusses the achieved accuracy. It also addresses open questions such as roughness evolution, layer stress, and the interpretation of metrology data.

Wolter mirrors work as imaging optics of X-ray telescopes. We have been developing a Wolter mirror for the FOXSI-4 project in 2023 using a high-precision Ni electroforming process. The figure accuracy of mirrors is one of the main factors determining the spatial resolution in X-ray imaging. In this study, we optimized the electrodeposition conditions from the viewpoint of the uniformity of film thickness. The simulation model was developed to correctly predict the film thickness distribution before fabrication, whose parameters and boundary conditions were determined through electrochemical experiments. The model calculates the distribution of current density on the surface of the cathode by finite element analysis. In this paper, we report the current status of the electroforming process specializing in Wolter mirrors in X-ray telescopes.

The hard X-ray adaptive mirror optics will play an important role at next generation light sources. A dynamic mirror bender with capacitive sensor array as an in-situ mirror profiler is used for initial test for hard x-ray zoom optics has been designed and constructed. Previous work showcases the dynamic control of this elliptically bent hard X-ray mirror through applying a combination of neural networks algorithm and feedback control. In this paper, we present further control enhancement with machine learning techniques through optimization of the number and placement of the capacitive sensors and new sensor calibration with video-based coordinate measuring machine.

A new type of x-ray facility, the Beam Expander Testing x-ray facility (BEaTriX), has been designed and is now under construction at INAF– Osservatorio Astronomico di Brera (Merate, Italy) to perform the acceptance tests of the silicon pore optics modules of the ATHENA X-ray telescope. Crystals of high perfection and large dimensions are needed in order to obtain a wide beam (20 × 6 cm²) with an X-ray divergence <0.5 arcseconds and a x-ray energy purity DeltaE/E<10^-5. To generate x-ray diffracted beams at an X-ray energy of 1.49 keV, ammonium dihydrogen phosphate (ADP) crystals have been considered among other possible choices, because of their reported crystal quality and because they can be grown at sufficiently large size. In the present paper, the results of the characterization of crystalline quality and lattice planarity of a 20 × 20 × 2 mm³ ADP sample are reported.

One-dimensional wave calculation is implemented for the synchrotron radiation source and optics with a crystal monochromator. Wave propagation on the crystal surface of the monochromator is simulated using the Riemann function, which is an analytical solution of Takagi-Taupin equations. For simplicity, Gaussian-beam approximation for undulator radiation is applied. The Pedellösung effect near the crystal surface of semi-infinite Bragg-case crystal is treated. It is shown that the beam profile is modified due to Pedellösung effect of 10 μm or more through the crystal monochromator. This is more remarkable for higher order reflection because of longer Pedellösung distance.

Low groove density gratings with blaze angles as low as 0.1‡ are required for plane grating monochromators for x-ray synchrotron and Free Electron Laser applications. To achieve so small a blaze angles we developed a process of reduction of the blaze angle of a coarse Si grating fabricated by anisotropic wet etching. The coarse grating with a blaze angle of 4° is planarized by a polymer layer and then plasma etching is applied to remove the polymer and underlying silicon material. The appropriate ratio of etch rates of Si and the polymer material provides reduction of the groove depth and the blaze angle. We developed a set of reduction recipes which provide blaze angle reduction down to 0.04° with high accuracy and which preserves the perfect triangular shape of the grooves. The ultra-low blaze angle grating coated with a Mo/Si multilayer exhibits a record diffraction efficiency of 58% due to the perfect match of the groove depth with the multilayer d-spacing. This opens up wide possibilities for making highly accurate and efficient diffraction gratings for tender x-ray, free electron laser, and EUV lithography applications. The low blaze angle gratings have a perfect triangular groove profile and highly smooth surfaces of the blazed facets which ensures high diffraction efficiency of the x-ray gratings.

There is a large performance gap between conventional X-ray sources and synchrotron radiation sources. An Inverse Compton Scattering (ICS) source can provide a narrow-band, high flux and tunable X-ray source that fits into a laboratory at a cost of a few percent of a large synchrotron facility. Here we present an ICS source design that is more than two orders of magnitude brighter than sources currently in operation, with applications in research, industry, and radiotherapy.

Since more than ten years, MetalJet sources, based on liquid-metal-jet technology, are successfully operated in many labs over the world. By using a high-speed jet of liquid metal, instead of the traditional solid- or rotating anode, it has been demonstrated that a much higher power can be applied to the anode. Since melting of the anode is thereby no longer a problem as it is already molten, MetalJet has achieved an at least 10x significantly higher brightness than the conventional solid-anode microfocus tube with the X-ray spot size range of 5- 40 µm. Key applications include X-ray diffraction and scattering, and several publications have also shown very impressive imaging results using liquid-metal-jet technology, especially in phase-contrast imaging and X-ray microscopy. The well-established way to obtain the ultimate resolution for X-ray microscopy is to use X-ray optics. Such optics normally limits the bandwidth of the spectrum, and thus requires a high brightness and relatively monochromatic X-ray source. MetalJet offer a sharp, high-intensity Kα line from Gallium emitted from a small focal spot, making a considerably larger fraction of the flux useful in the optics setup. This higher brightness makes broad applications possible also at home laboratory. Additional feature given by MetalJet is the capability of imaging copper (Cu)-rich electronics with high contrast, thanks to the usage of Gallium rich anode material. It has the K-alpha line that is slightly above the absorption edge of Cu, where a sudden drop in X-ray transmission happens and a good contrast between Cu and background elements, ex. Silicon is expected. Therefore, MetalJet source could be a good hand in imaging copper conductors of the obsolete computer chips, as well as other copper-contaminated materials in transport, construction applications. Phase-contrast imaging achieves a significant improvement on the contrast for low absorbing materials. However, it requires the X-ray source to have small emission spot (normally microfocus), high flux and stability, due to the limited lab space and/or adding of optics to retrieve the signal reliably. Therefore, the high brightness MetalJet source is a good match for doing phase-contrast imaging with compact laboratory setup, by enabling shorter exposure time, higher imaging resolution and contrast. Besides, the high stability of the source perfectly matches the requirement of the associated phase-contrast imaging techniques. Moreover, with the high brightness MetalJet source, X-ray fluorescence imaging has been transferred successfully from synchrotron to laboratory setup and its performance has reached the level of synchrotron-level. In this presentation we will go over some recent developments in the technology that bring 70 times more brightness to the lab than a solid target X-ray tube. We will also discuss some examples from the users who have used the technology to bring synchrotron application to the lab.

This paper presents the results of using the laboratory X-ray system to study the diamond X-ray optics: single-crystal diamond plates and diamond X-ray parabolic refractive lenses. The system is equipped with the Excillum MetalJet D2+ 70kV high-brightness X-ray source with a liquid GaIn anode. To analyze the defects of the crystal structure, the X-ray diffraction imaging (topography) technique was applied. Two-dimensional images of the diamond plate were experimentally recorded from (111) crystal plane with 12 μm and 1.5 μm resolution. The images of the X-ray semi-lens were recorded from (400) and (220) crystal planes with 20 μm resolution. These topographs displayed various defects, such as growth striations and dislocations.

The BEaTriX (Beam Expander Testing X-ray) facility, being completed at INAF-Brera Astronomical Observatory, will represent an important step in the acceptance roadmap of Silicon Pore Optics mirror modules, and so ensure the final angular resolution of the ATHENA X-ray telescope. Aiming at establishing the final angular resolution that can be reached and the respective fabrication/positioning tolerances, we have been dealing with a set of comprehensive optical simulations. Simulations based on wave optics were carried out to predict the collimation performances of the paraboloidal mirror, including the effect of surface errors obtained from metrology. Full-ray-tracing routines were subsequently employed to simulate the full beamline. Finally, wavefront propagation simulation allowed us assessing the sensitivity and the response of a wavefront sensor that will be utilized for the qualification of the collimated beam. We report the simulation results and the methodologies we adopted.

To increase the X-ray flux generated in a medical linear accelerator (LINAC), it is necessary to remove the heat deposited in the target by the impinging electrons. Higher X-ray fluxes are required for treatments that apply significant doses of radiation in a short period of time. We analyzed a variety of targets and cooling geometries in a typical LINAC. The Monte-Carlo code Geant4 was first used to determine the X-rays produced and the energy deposited in the targets, and the temperature distribution in the target was determined using finite-element analysis. Improved target/cooling designs to produce higher X-ray flux are described and quantified.

In this talk, we will summarize the key parameters for combining multilayer optics and microfocus tubes to achieve collimated or focused X-ray sources with high brilliance. The main part of the talk will explain the application-dependent design and capabilities of our newly developed custom metal-ceramic tubes and how to match them with our advanced multilayer optics. Stand-alone custom tubes and optics made possible by the advanced knowledge of the two centerpieces of the source will also be covered. Applications include crystallography, detector calibration, or as a tool at synchrotrons during downtime or con-struction periods.

A Laser-Driven Plasma X-ray Source (LPXS) can provide intense, hard X-rays in femtosecond pulses emitted from a micrometer-size spot on a recirculating liquid-metal target. Unlike X-ray tubes based on electron beams, which are subject to constraints of the electron optics and space-charge effects, there is no fundamental limit to the amount of laser power that can be concentrated into the micrometer focus. With the increasing availability of industrial picosecond and femtosecond laser systems it now is practical to offer high average X-ray flux, combined with far higher brilliance and far shorter pulses than possible with X-ray tubes. Because the laser target in an LPXS is a liquid-metal, each laser shot encounters a fresh surface. Metal vapor and droplets are collected and recirculated to the target metal pump for maintenance-free operation. Hard X-rays are generated at tens of keV photon energies consisting of continuum radiation and, depending on the target material composition, of Ga-K, Bi-K or In-K emission lines.