Current optical finishing technology limits the choices for synchrotron radiation materials to a relatively few materials: fused silica and ULE^TM, silicon, CVD silicon carbide, and electroless nickel. We review, in a general way, those materials and several others that can be finished to the required figure and finish levels, generally considered to be < 3 microradians rms and < 5 angstroms rms. With the objective of material choices for synchrotron beam line mirrors in mind, we briefly discuss dimensional stability, cooling, bending, polishing, and manufacturing procedures. After discussing specific materials: those previously mentioned and aluminum, Glidcop^TM, invars, and steels, we conclude that metals are best from an engineering and cost standpoint, but ceramics, including silicon are best from a polishing standpoint.

An elliptically bent mirror of total length 1.25 m has been developed at the Advanced Light Source (ALS) for focusing soft x-rays. The mirror is used to produce a small, high flux density illuminated field of view for a Photo-Emission Electron Microscope. The requirement to collect the maximum horizontal aperture with the need to highly demagnify the source leads to a mirror with a wide range of curvatures along the surface. This combined with the need to produce a low slope error surface at a reasonably low cost has required us to develop a mirror based on the controlled bending of a flat substrate. This is an extension of several other mirror projects at the ALS where controlled bending of glass and metal substrates has been used in micro-focusing applications. Those mirrors however are a maximum of 200 mm long, and in this paper we describe the new challenges we have faced and the solutions we have adopted in developing a long and highly elliptical mirror. The mirror described here is manufactured from a low carbon steel (1006) which is capable of good dimensional stability, it is electroless nickel plated for polishing, and is bent into an elliptical shape by the application of unequal couples. We describe the mirror fabrication process, the mechanical details of the bending mechanism and the experimentally measured slope error from an ellipse. The final mirror has an rms roughness of 6 angstroms (rms), a full aperture (1.1 m) slope error of 14 (mu) rad (rms), and a slope error of < 3 (mu) rad when optimized over approximately 2/3 of the required optical length (0.917 m).

A large 5-axis control ultraprecision grinding machine has been developed for making synchrotron-radiation mirrors with high accuracy. The positional and angular resolutions of the machine are 10 nm and 0.0002 degree, respectively. The dimensions of the machine are 3.3 m by 2.7 m by 4.4 m in height. The machine can generate non-axisymmetric aspheric surfaces on CVD-SiC material by a disc-type metal-bonded diamond wheel. An electric micrometer has been set near a grinding head for measuring the form error of ground surface in conformity with the machine movement due to the cutter location data. A series of the measured form errors corrects the former cutter location data automatically and the next grinding operation will be performed by the new cutter location data. A CVD-SiC material of 510 mm by 110 mm was ground into a toroidal surface of 750 nm in shape accuracy by the fifth grinding operation with the fourth correction of cutter location data. More than 99% of toroidal surface area have a form accuracy less than 500 nm. 3.3 nm rms surface roughness was obtained by the ultraprecision grinding using a SD4000N150M metal-bonded diamond wheel.

We report the achievement of a superpolished surface, suitable for x-ray reflection, on bare stainless steel. The rms roughness obtained on various samples varied from 2.2 to 4.2 angstroms, as measured by an optical profiler with a bandwidth 0.29 - 100 mm^-1. The type 17-4 PH precipitation-hardening stainless steel used to make the mirrors is also capable of ultrastability and has good manufacturability. This combination of properties makes it an excellent candidate material for mirror substrates. We describe the successful utilization of this type of steel in making elliptical-cylinder mirrors for a soft-x-ray microprobe system at the Advanced Light Source, and discuss possible reasons for its unusual stability and polishability.

While many of the government funded research communities over the years have put their faith and money into increasingly larger synchrotrons, such as Spring8 in Japan, and the APS in the United States, a viable market appears to exist for smaller scale, research and commercial grade, compact synchrotrons. These smaller, and less expensive machines, provide the research and industrial communities with synchrotron radiation beamline access at a portion of the cost of their larger and more powerful counterparts. A compact synchrotron, such as the Aurora-2D, designed and built by Sumitomo Heavy Industries, Ltd. of japan (SHI), is a small footprint synchrotron capable of sustaining 20 beamlines. Coupled with a Microtron injector, with 150 MeV of injection energy, an entire facility fits within a 27 meter [88.5 ft] square floorplan. The system, controlled by 2 personal computers, is capable of producing 700 MeV electron energy and 300 mA stored current. Recently, an Aurora-2D synchrotron was purchased from SHI by the University of Hiroshima. The Rocketdyne Albuquerque Operations Beamline Optics Group was approached by SHI with a request to supply a group of 16 beamline mirrors for this machine. These mirrors were sufficient to supply 3 beamlines for the Hiroshima machine. This paper will address engineering issues which arose during the design and manufacturing of these mirrors.

This contribution focuses on the fabrication and metrology of various synchrotron radiation (SR) mirrors and grating substrates at Carl Zeiss. Due to the increased demand in high quality and high heat load SR optics new materials have entered the optical shop since the last few years. Currently the variety of materials ranges from Zerodur^TM (a glass ceramic with a thermal expansion of approximately equals 0) through metals as Ni on Al to Silicon (Si) or even Silicon Carbide (SiC). Si is of special interest due to its thermal properties (expansion and conductivity) in high heat load application combined with its extremely low micro roughness of about 0.1 nm RMS and therefore low scattering contribution. Depending on the mirror geometry sub-arcsec quality with respect to the slope errors is achieved for all materials. The current length limit of the mirrors is about 1.5 m. In the paper accent is put on the metrology in the sub-arcsec regime (down to 0.1'). Special adapted software and evaluation strategies together with correct handling of the interface substrate/stylus of the metrology device are necessary to cope with the 0.1' mirror class. A review of recent fabrication results is given.

The plane grating monochromator is to be used with the 480 MeV ((lambda) _c equals 61 angstroms) consists of a, plane grating, plane mirror (500 mm X 50 mm) and an ellipsoidal mirror (300 mm X 50 mm, & semi-major axis 39935.7 mm, semi-minor axis 378.84 mm and eccentricity is 0.999955 viz center of the mirror x equals 38433.772 mm, y equals 102.920 mm). The technology for fabricating the plane mirror and the ellipsoidal mirror is being developed at Photonics Division, Indian Institute of Astrophysics. The optical requirement for these mirrors in terms of tangent error better than 1 sec of arc and the micro roughness better than 5A^o is dictated by the design parameters of the monochromator. With these specifications in mind Zerodur substrate material has been chosen in the first phase of the development. For the fabrication of the ellipsoidal mirror a new machine has been designed and fabricated for different stages of grinding, polishing and figuring. The flat and the ellipsoidal mirror are in the final stages of figuring. The paper presents the technology development for manufacturing of these mirrors and the measurement procedures adopted during the fabrication. Problem areas have also been discussed.

Catastrophic damage has been observed in some ZERODUR mirrors used as first mirrors in two beam lines at the National Synchrotron Light Source. Despite the high reflectivity of the coatings used on these mirrors, a significant flux of high energy photons penetrates below the coating and is absorbed in the substrate. Although model calculations indicate that the local temperature does not increase significantly, we suspect that over long time periods the absorbed flux produces structural changes in the material, leading to a build-up of surface stress, gross figure changes, and growth of fractures. These changes are probably related to the nature of the two-phase glass- ceramic composition of the ZERODUR material. Metal mirrors and single-phase materials do not exhibit such catastrophic damage under similar exposure conditions.

Single crystal silicon has become readily obtainable and relatively inexpensive as a result of the production facilities set up to serve the semiconductor industry. It also has desirable properties for x-ray mirrors; it can be polished to a high degree of smoothness, has good mechanical properties, and high thermal conductivity. Polycrystalline silicon, which has greater mechanical strength, is also available. For these reasons we have used silicon mirrors exclusively at two bending magnet beamlines and one undulator beamline at the Advanced Light Source. We describe here two implementations of silicon mirrors: (1) a fixed radius design for high heat loads, which is side cooled by contacting to a water cooled block with Ga-In eutectic, and (2) designs in which a variable radius and/or an elliptical mirror figure are achieved by elastically bending a flat strip of the appropriate cross-sectional profile. Computed and measured performance figures are presented for each case.

A need for a conical grazing incidence x-ray mirror was identified for a virus crystallography beam line at Argonne National Laboratory. This mirror would allow a synchrotron light source to be conveniently focused to an experimental station, thereby providing a working distance suited to the practical limitations of the experimental hall. The use of such a mirror was first verified by optical design analysis, which, in turn, prompted the development of special optical fabrication and testing procedures validated by the successful manufacture of a 1/3 size surrogate optical component. The successful conclusion of the developmental work then led to the manufacture of an internally cooled mirror of single crystal silicon, 1000 mm in length, having a cone angle of 0.957 milliradian. This paper discusses the construction of the full size mirror and the results obtained using second generation refinements of the previously demonstrated optical fabrication procedures.

We present a description of two types of bendable devices that have been manufactured and tested by SESO: bendable mirror with external bending mechanism and cooling, and long bimorphic bendable mirror with piezoelectric drive. A comparison chart of these devices will show the advantage of each solution.

The Long Trace Profiler, an instrument for measuring the slope profile of long X-ray mirrors, has been used for adjusting bendable mirrors. Often an elliptical profile is desired for the mirror surface, since many synchrotron applications involve imaging a point source to a point image. Several techniques have been used in the past for adjusting the profile measured in height or slope of a bendable mirror. Underwood et al. have used collimated X- rays for achieving a desired surface shape for bent glass optics. Nonlinear curve fitting sing the simplex algorithm was later used to determine the best fit ellipse to the surface under test. A more recent method uses a combination of least squares polynomial fitting to the measured slope function in order to enable rapid adjustment to the desired shape. The mirror has mechanical adjustments corresponding to the first and second order terms of the desired slope polynomial, which correspond to defocus and coma, respectively. The higher order terms are realized by shaping the width of the mirror to produce the optimal elliptical surface when bent. The difference between desired and measured surface slope profiles allows us to make methodical adjustments to the bendable mirror based on changes in the signs and magnitudes of the polynomial coefficients. This technique gives rapid convergence to the desired shape of the measured surface, even when we have no information about the bender, other than the desired shape of the optical surface. Nonlinear curve fitting can be used at the end of the process for fine adjustments, and to determine the over all best fit parameters of the surface. This technique cold be generalized to other shapes such as toroids.

Ray-tracing plays an essential role for the design of a synchrotron radiation beamline optics. Nevertheless, it can also be extremely useful during the commissioning phase of a beamline. At that moment, it is possible to include real surface figure errors in the computer simulation of the optical devices. The resulting focal spot size and photon flux values are the final targets for the experimental optimization and alignment of the optics setup. We report on extensive ray-tracing of the mirror systems of the two beamlines placed at the ESRF insertion device 12. Slope errors measured after mirror delivery are included in the calculations. It is demonstrated how slope errors with characteristic periodicity between 1 and ca. 1/20 of the mirror length can affect the focal spot shape, size and position. In particular, they can create structures or satellites in the focal spot. The distortions from the ideal shape are generated by the polishing process itself and are intrinsic to each single mirror. Comparison between the effects of slope errors in ray-tracing using either real (measured) surfaces or numerically generated ones are also reported.

XOP (X-ray OPtics utilities) is a graphical user interface (GUI) created to execute several computer programs that calculate the basic information needed by a synchrotron beamline scientist (designer or experimentalist). Typical examples of such calculations are: insertion device (undulator or wiggler) spectral and angular distributions, mirror and multilayer reflectivities, and crystal diffraction profiles. All programs are provided to the user under a unified GUI, which greatly simplifies their execution. The XOP optics applications (especially mirror calculations) take their basic input (optical constants, compound and mixture tables) from a flexible file-oriented database, which allows the user to select data from a large number of choices and also to customize their own data sets. XOP includes many mathematical and visualization capabilities. It also permits the combination of reflectivities from several mirrors and filters, and their effect, onto a source spectrum. This feature is very useful when calculating thermal load on a series of optical elements. The XOP interface is written in the IDL (Interactive Data Language). An embedded version of XOP, which freely runs under most Unix platforms (HP, Sun, Dec, Linux, etc) and under Windows95 and NT, is available upon request.

New third-generation synchrotron radiation sources that are now, or will soon, come on line will need to decide how to handle the testing of optical components delivered for use in their beam lines. In many cases it is desirable to establish an in-house metrology laboratory to do the work. We review the history behind the formation of the Optical Metrology Laboratory at Brookhaven National Laboratory and the rationale for its continued existence. We offer suggestions to those who may be contemplating setting up similar facilities, based on our experiences over the past two decades.

Traditional optical manufacturing methods employing both conventional and modern interferometric techniques, enable one to measure surface deviations to high accuracy, e.g. up to (lambda) 100 for flats (6 nm P-V). In synchrotron radiation applications the slope error is an important criterion for the quality of optical surfaces. In order to predict the performance of a synchrotron radiation mirror the slope errors of the surface must be known. Up to now, the highest achievable accuracy in the production of synchrotron radiation mirrors and in the measuring methods did not fall significantly below the 0.1 arcsec rms limit (spherical and flat surfaces). A long-trace profiler (LTP) is ideally suited for this task since it directly measures slope deviations with high precision. On the other hand, using an LTP becomes very sensitive to random and systematic errors at the limit of 0.1 arcsec. The main influence is the variation of the surrounding temperature in creating temporal and local temperature gradients at the instrument. At BESSY both temperature and vibrations are monitored at the most sensitive points of the LTP. In 1996 BESSY started a collaboration with a neighboring optical workshop combining traditional manufacturing technology with quasi- in-process high precision LTP measurements. As result of this mutual polishing and LTP measuring process, flat surfaces have been repeatedly produced with slope errors of 0.05 arcsec rms, e.g. 1 nm rms and 3 nm P-V (approximately equals (lambda) /200).

This paper describes the development of a prototype instrument of the Vertical Scanning Long Trace Profiler (VSLTP) under a SBIR Phase II grant from NASA. The instrument is capable of scanning shell mirrors with a diameter as small as 100 mm for a travel distance of 700 mm in vertical configuration. Main components of the optical system are described. It has a beam separation set, a beam splitting set, a Fourier transform lens system, a penta prism pair, a Risley prism pair and a cylinder lens. The main hardware and software for implementation of the prototype instrument are also presented. They include the major mechanical structure, 9-axis motion control system and the data acquisition and analysis software. The design of the optical and mechanical systems makes the VSLTP very tolerable to the deformation of the slide deformation, laser pattern shift and fluctuation due to temperature change. Results obtained from the Phase I show that the VSLTP instrument is capable of a measurement accuracy of 50 nm for the height and 1 microradian for the slope.

In this paper we describe an x-ray long trace profiler that takes an x-ray synchrotron beam as a wavefront reference. According to results of experiments conducted on the Optics Beamline at the ESRF, this instrument allows us to measure surface slope errors with precision and accuracy better than 25 nrad (rms) and 50 nrad (rms), respectively, with a lateral resolution of 5 mm in the meridional and less than 1 mm in the sagittal direction. A very similar technique was developed to figure in situ mirrors mounted on mechanical benders into a stigmatic shape for microfocusing purposes. Micron spot sizes were achieved without difficulty and submicron precision should be possible. The technique is particularly useful if energy tunability is needed. The emphasis has been put on automation and speed of the measurement.

Phase-measuring, lateral-shearing interferometry has been carried out on a multilayer-coated extreme-ultraviolet (EUV) Schwarzschild camera at the multilayer coating's center wavelength. The measured wavefront error was 0.096 waves rms at a wavelength of 13.5 nm. The interferometer employed in the measurement was developed to evaluate the image quality and improve the alignment of cameras for EUV lithography and was previously shown to have a sensitivity of 0.021 waves rms or better at an operating wavelength of 13 nm.

Manufacturing for large-scaled integrated circuit requires a large exposure area and high throughput. According to the SIA road map, 16 Gbit DRAM requires exposure area of 26 mm X 44 mm for a 0.1-micrometers generation. In order to determine these feasibility, we designed at imaging optics which is based on three aspherical-mirror optics for EUVL. This designed optics is a very compact one, and the optics can achieve a resolution of less than 0.1 micrometers and an ring field of 26 mm X 1.0 mm on a wafer. In assembling the demagnifying optical system, various adjustment errors such as decenter, tilt and despace affect one another in an intricate way and degrade the system performance in a complicated manner. It is therefore important in practice to adjust the system as a whole rather than trying to optimize the effects of individual adjustment mirrors on the resolution by fulfilling respective tolerances. Another important factor affecting the system performance is surface figure error of aspherical mirrors. The surface figure error of aspherical mirror is estimated by calculation of ray tracing method. We obtained the tolerance of the figure errors of M1, M2, and M3 to be 0.66 nm, 0.75 nm, and 0.90 nm for replicating 0.1-(mu) nm-pattern, respectively. It is found that these values are twice or three times larger than the values obtained from Marechal criteria.

We present an experimental survey of the performance of various multilayer systems to be used in the soft x-ray range with special emphasis on the water window. The multilayers have been designed as high reflectance normal incidence mirrors and, for polarimetry purposes, as detectors for circularly polarized synchrotron radiation, respectively. Seven different multilayer systems with spacer materials of C or the transition metals Sc, Ti, V, Cr in combination with the absorber materials Fe, W and Ni were investigated. At the 1s- and 2p absorption edges, respectively, they show a strong resonant enhancement of the reflectance due to anomalous dispersion. By tailoring the layer thickness and the thickness ratio for use at and below the resonance energy in normal incidence ((theta) equals 90 degree(s)) and at (theta) equals 45 degree(s), respectively, an excellent performance with respect to reflectance, transmission and polarizance, respectively, in the water window was achieved for multilayers with period thicknesses down to 1.4 nm.

W-B₄C multilayers with single d-spacing period of 2.2 nm have been deposited on 330 long by 50 mm wide Si substrates to be used as monochromators for a computed tomography application. Using magnetron sputtering and a substrate masking technique, d-spacing uniformities of +/- 0.86% and +/- 1% were obtained over a 180 mm by 100 mm area for 2.2 nm and 4.2 nm d-spacings respectively. Two separate processes were used to coat the 330 mm long substrate, wherein half of the substrate was coated in each process. A similar process was used to deposit depth graded W-B₄C supermirrors on Si and CVD SiC substrates for a beamline pre-mirror application. The 330 mm long by 50 mm wide Si and 300 mm long by 79 mm wide SiC substrates were coated with 20 bi-layer supermirrors with d-spacings ranging from 4.4 nm to 10.8 nm. For an angiography research application laterally graded W-B₄C multilayers were deposited on 150 mm by 120 mm silicon substrates. A strong nonlinear d-spacing gradient, from 1.6 nm to 3.8 nm was achieved across the mirror's surface in an attempt to provide uniform intensity over the reflected area. The maximum and minimum d-spacing gradient was 0.06 nm/mm and 0.003 nm/mm, respectively. We measured and mapped the d-spacing gradient using a custom Cu-K_a diffraction system. The measured d-spacings were within +/- 1.5% of the intended d-spacings.

As part of a project to develop methods of placing highly reflective multilayer coatings on the inside of Wolter I mirrors, we have been pursuing a program of measuring flat mirrors. These flats have been produced and examined at various stages of the process we plan to use to fabricate multilayer coated Wolter I mirrors. The flats were measured via optical profiler, AFM, (both done at Brookhaven National Lab) and X-ray reflection (done at the Argonne National Lab Advanced Photon Source). We report for the first time, to our knowledge, the successful placement of multilayers on an electroform by depositing the multilayers on a master and then electroforming onto this master and removing the multilayers, intact, on the electroform. This process is the one we plan to use to place multilayers on the inside of Wolter I optics.

The characteristics of X-ray diamond-like mirrors and Me-C mirrors were compared. The effect of influence temperature and radiation on reflectivity and the bandwidth of Bragg peaks were investigated. Temperature stability in the range up to 400 C was studied. The valuation of the radiative stability of mirrors was evaluated.

The efficient fabrication of large grazing incidence mirrors can often impose special needs for fabrication and coating equipment, facilities, and raw materials. The economic realization of such an optic can be readily accomplished through close interactions between the mirror user, the fabricator, and the manufacturer of the raw material designated as the mirror substrate. The manufacture and delivery of a flat 1.4 meter long synchrotron mirror for use at x-ray wavelength is used to provide an example of effective interactions between participating entities. The fabrication, testing, and coating processes are described and the results obtained are presented in the form of measurement data for surface figure and surface roughness.

Of the many methods used to focus x-rays, the se of mirrors with an elliptical curvature shows the most promise of providing a sub-micron white light focus. Our group has been developing he techniques of controlled bending of mirror substrates in order to produce the desired elliptical shape. We have been successful in producing surfaces with the required microradian slope error tolerances. Details of the bending techniques used, results from laboratory slope error measurements using a Long Trace Profiler and data from the measurement of focus shape using knife edge and imaging methods using x-rays in the 5 - 12 KeV energy range are presented. The development of a white light focusing opens many possibilities in diffraction and spectroscopic studies.

We report on first results obtained with a novel, x-ray- based method that permits to correct residual slope errors of curved crystals to (mu) rad accuracy. It consists of two steps. The first is to measure the slope error very precisely, the second to shape the sides of the crystal plate to be bent according to the correction calculated from simple bending theory and thus to achieve a substantial improvement of the lattice plane slope error. The same technique can be applied to elastically bent mirrors or multilayers.