The inclined double crystal monochromator arrangement is very effective in handling high heat loads and holds considerable promise as a monochromator for undulator beams at third generation synchrotrons. Results for the ideal inclined crystal case have been obtained by dynamical diffraction calculations, and diffraction results for the (111) reflection of silicon are presented for an inclination angle of 85 degree(s) and energies of 5 keV and 13.84 keV. The diffraction characteristics resemble closely diffraction from a symmetric (111) plane of silicon. However, the inclined and noninclined cases are not identical. Diffraction in the inclined case is slightly different due to refraction. The full width at half maximum of the Darwin-Prins reflectivity curve is slightly increased (approximately 1%), and the angles of the outgoing beam after one reflection are slightly altered. That is, except for a wave incident at the Laue point in reciprocal space, the diffraction is always slightly asymmetric. The effect can be exactly reversed by an identical second crystal in the (+,-) arrangement.

Sagittal focusing of undulator radiation is shown to be compatible with the proposed inclined double-crystal monochromator geometry for heat load reduction. The focusing aberrations are shown to be negligible for typical undulator-beam divergences over a range of magnifications from 1:2 to 6:1 and energies from 3 to 40 keV. The inclined geometry reduces the required sagittal curvature of the focusing crystal compared to focusing with conventional symmetric crystals; hence, focusing is possible at higher X-ray energies and with less anticlastic bending. In addition, anticlastic stiffening ribs project a smaller footprint to the beam so that the achievable focal spot size is potentially better than with conventional symmetrically cut crystals.

The high power levels found in modern synchrotrons require the use of cooled beamline optics in order to maintain optical distortion at acceptable levels. The best cooling methods are those which give acceptable distortion levels both economically and reliably. We review analytical studies we have performed on a number of cooled optics for synchrotron beamlines. Studies involving a wide range of power loadings, beam profiles, and optic geometries are discussed.

Detailed ray-tracing studies and preliminary thermal analysis are presented for two mirrors that will be installed at the Advanced Photon Source. The first mirror is designed to accept white radiation from a bending magnet. This radiation is 5 mrad in the horizontal direction and 73 (mu) rad in the vertical. A 1.5 m long toroidal mirror is planned. The second mirror accepts radiation from an undulator. This radiation is 55 (mu) rad and 25 (mu) rad in horizontal and vertical directions, respectively. A 70-cm toroidal mirror is planned. Both mirrors are optimized for 1:1 focusing in order to minimize optical aberrations. Design specifications are presented. Suitable materials for the mirror substrates and reflective surfaces are discussed as well.

A new concept of adaptive silicon crystal monochromator for high heat load insertion devices is proposed in order to dynamically correct the thermal distortion by piezoelectric translators as a function of beam power. Shapes and dimensions of cooling channel was optimized by testing various types of grooved crystals using a 27-pole wiggler magnet beamline. The results indicate that the cooling efficiency of grooved silicon crystals can be improved by replacing a conventional semicircular cooling channel with a flat cooling channel with an optimized dimension. The results of rocking curve measurement showed an energy resolution ((Delta) E/E approximately 2 X 10^-4). A prototype of adaptive first crystal with grooves was fabricated using a new diffusion bond technique. It was found that the crystal surface was precisely bent to a radius of several hundred meters by a piezoelectric device. An adaptive approach to the second crystal using an inchworm mortor was presented for dynamical sagittal focusing for realizing the energy-independent horizontal focus.

This paper describes R&D projects dealing with x-ray mirrors at the ESRF. Some considerations about materials selection and elastically bent mirrors will be discussed. Development of new technologies such as an adaptive mirror and a long trace profiler will be outlined.

Usually perfect crystals are used as x-ray monochromators for low-emittance/high brilliance beamlines because their reflection widths often match the angular divergence of synchrotron x- ray beams. However, this matching is not always the best condition to optimize an experiment and in several cases intensity can be gained without loss in resolution by choosing mosaic crystals. Moreover, the matching is quite generally not fulfilled at high x-ray energies and here mosaic crystals would be especially useful. There are other applications presently under consideration at the ESRF and elsewhere, in particular for beryllium and diamond single crystals that have the advantage to absorb an only small fraction of the incoming flux while reflecting efficiently the useful photons thereby decreasing the heat load problem to an acceptable level. The inconvenience of increasing the angular beam divergence inherent to mosaic crystals can often be tolerated and substantially reduced in the scattering plane by inserting a second crystal. The expected efficiency depends on the uniformity of the mosaic distribution that is generally not easy to obtain as shown by rocking curve techniques and by topography. Experimental results obtained with several single crystal materials are presented and compared with their theoretically possible performance. Various applications presently proposed are then mentioned.

Some novel x-ray optics for synchrotron light source using dynamic diffraction are discussed. In addition to the usual 'energy monochromator', perfect crystal optical devices can be used as an angular collimator, spatial transformer, as well as a polarization modifier.

The dynamical theory of x-ray diffraction in crystals is a theory of wave propagation in periodic structures and, as such, its application to the diffraction by artificial periodic multilayered structures should, in principle, be straightforward. In practice, this is not so; the conventional theory involves a number of approximations that may fail for multilayered structures. The central problem is that of calculating multiple scattering effects: those that occur within a single bi-layer and those that involve different bi-layers. A modified Darwin dynamical theory of diffraction is formulated, which, once the scattering from a single bi-layer is known, allows the calculation of the diffraction by the full multilayer to be performed exactly without any further approximations. In particular, many-beam effects are included in a very straightforward way. For the calculation of the transmission and reflection coefficients of the single diffuse bi-layer two alternatives are offered: either one uses an improved kinematical theory (including corrections for index of refraction, absorption and total reflection) which has the advantage of rather general applicability provided the bi-layer is not too thick, or, one adopts for the single interface the special Epstein profile which allows for full consideration of multiple scattering effects. We find that the scattering by a diffuse boundary differs from that of a sharp boundary by a factor which is not of the Debye-Waller form, that there is an increased sensitivity to diffuse structure close to weak (nearly forbidden) reflections, and that the analytical treatment described here offers a very appreciable increase in numerical efficiency over recursive methods of calculation.

The insertion-device-based, third-generation, synchrotron radiation sources now under construction in Europe, the USA, and Japan bring new opportunities and challenges in the design and manufacture of x-ray optics. These high brightness sources provide new opportunities to overcome some of the outstanding problems associated with nuclear resonant monochromatization of synchrotron radiation. New methods such as polarizing monochromators, and zone plates provide alternative methods for production of (mu) eV-neV resolution in the hard x-ray regime. The design principles, and characterization, and performance of crystal monochromators and of nuclear coherent scattering optics, including Grazing Incidence Anti Reflection (GIAR) films, multilayers, zone plates, as well as single crystals are discussed.

Certain types of x-ray microscopes require coherent beams of soft x-rays, and thus are amongst the most brightness-hungry of synchrotron radiation experiments. We consider here what advances third generation sources will and will not offer to several kinds of x-ray microscopes.

Two types of fabrication methods have been developed to fabricate Fresnel zone plates for focusing x-rays in the 5 - 25 keV energy region. These two fabrication methods are discussed in terms of spatial resolution and focusing efficiency, which are two important parameters that characterize the performance of a Fresnel zone plate. Experimental characterization of the zone plates fabricated by the two methods are described and the results are discussed.

A circularly polarized X-ray (CPX) beamline has been constructed at 6.5 GeV Accumulation ring. The insertion device is an elliptical multipole wiggler. The CPX from this device is used by the following two branch lines. One is for magnetic Compton scattering and/or high resolution Compton scattering experiments. The monochromator of this branch line is a quasi- doubly bent crystal monochromator that comprises an array of twenty pieces of water-cooled singly-bent crystals. The obtained performance is as follows; the energy range is 40 - 70 keV, the flux is 6 X 10¹² at 60 keV, the energy resolution (Delta) E/E equals 1.4 X 10^-3, and the beam size at the sample position is 3 X 8 mm². Another is for magnetic X-ray Absorption Near Edge Structure (XANES) and magnetic Bragg scattering experiments. The optics of this branch line is a combination of a saggital focusing double crystal monochromator and a bent plane mirror. In a moment, the monochromatized X- ray from 6 to 28 keV is available and the focused beam size is about 0.4 X 3 mm². The heat load problems at the above monochromators and some experimental results by using this beamline are also presented.

The ESRF beamline #6 is dedicated to polarization dependent spectroscopies at excitation energies ranging from 0.4 up to 20 keV. This broad energy range will be covered with two helical undulators (Helios-I and Helios II) providing the user with a full control of the photon polarization. Two kinds of optics will be made available: (1) low energy experiments (0.4 keV <EQ E <EQ 2.0 keV) will be carried out on a side-branch beamline equipped with a 'Dragon-type' grating spectrometer; (2) single crystal Bragg optics will be used above 2 keV on the straight branch part of the beamline. We report on the present status and optical arrangement of both branches. Special emphasis is put onto the polarization transfer in Bragg optics with elliptically or circularly polarized light. Various experimental configurations have been evaluated with respect to the figure of merit I.(tau) ², where I is the transmitted intensity and (tau) is the circular polarization rate. Operation of the beamline will start with a simplified, conservative optical configuration, while more challenging options require specific technical developments.

We give a brief summary of the requirements for water cooled optical components for the Advanced Light Source (ALS), a third generation synchrotron radiation source under construction at Lawrence Berkeley Laboratory (LBL). Materials choices, surface figure and smoothness specifications, and metrology systems for measuring the plated metal surfaces are discussed. Results from a finished water cooled copper alloy mirror will be used to demonstrate the state of the art in optical metrology with the Takacs Long Trace Profiler (LTP II).

Third generation synchrotrons such as the Advanced Light Source impose severe restrictions on the allowable optical surface tolerances associated with the mirrors and diffraction grating substrates, if the high quality beam characteristics are to be utilized. We describe some of the fabrication and metrology techniques used to attain sub-microradian slope errors and surface roughness of 2 angstroms RMS on water cooled metal components.

The large lattice parameter (a_o equals 23.44 angstroms) of cubic YB₆₆ together with its vacuum compatibility, mechanical properties and resistance to radiation damage makes this material well suited for use as soft x-ray monochromator in the 1 - 2 keV region. Crystals obtained by various growth modes of an indirect heating floating zone (IHFZ) technique are characterized with x-ray topography and rocking curve measurements using both laboratory and synchrotron sources. The results indicate that high quality single crystals of YB₆₆ large enough to accept at least 1 mrad of synchrotron beam can be produced.

An undulator beamline is under construction for micro-diffraction and micro small-angle scattering at the ESRF. The beamline will demagnify an approximately equals 100*100 micrometers ² undulator source point by an ellipsoidal mirror to approximately equals 10*10 micrometers ². The beam will be monochromatized by a Si-111 channel cut monochromator or W/Si multilayers. Optical techniques will be used for sample observation.

An X-ray microprobe is being built that will use a bending magnet port on the new Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory. A pair of elliptical multi-layer mirrors will be used to focus and monochromatize the white radiation beam from the synchrotron. A beam spot size of 1 micrometers X 1 micrometers will be produced with a bandwidth of 1 keV at 10 keV. The energy of the beam will be variable from 3 keV to 12 keV. With a counting time of 30 sec it should be possible to simultaneously measure femtogram amounts of elements from potassium to zinc.

A grooved crystal monochromator with Ge 620 reflections operating at Bragg angles around 89.5 degree(s) was constructed and characterized. A monochromatized beam in the forward direction with high energy resolution ((Delta) E/E equals 1.66 10^-5) and fine energy tuning performed by its temperature variation was obtained. Several back and forth reflections occur within the grooved crystal allowing the operation at Bragg angles very near to (pi) /2. High reflectivities, around 0.9, of the diffraction profiles in the back diffraction regime guarantees small losses in intensity. This monochromatized beam was used to obtain and measure transmitted diffraction profiles at Bragg angles equal to (pi) /2.

A nuclear monochromator using grazing incidence anti-reflection (GIAR) films of ¹¹⁹SnO₂ coated on a Pd backing mirror was designed, fabricated and characterized. ¹¹⁹SnO₂/Pd/quartz GIAR films were synthesized by a magnetron reactive sputtering technique. The films were characterized by x-ray scattering of 23.87 keV synchrotron radiation source. From the measurement of off-resonance reflectivity and the simulation of the resonant nuclear reflectivity, approximately 0.8 reflectivity with 10^-2 electronic reflectivity and an energy band width approximately 100 (Gamma) where (Gamma) is a natural line width, at a 2 mrad incident beam angle would be expected. The requirements and alternative methods to improve performance of a GIAR film nuclear monochromator were discussed.

The design principles, construction and characterization of a 4-bounce dispersive crystal monochromator is discussed. This monochromator is designed to reduce the bandpass of synchrotron radiation to 10 - 50 meV level, without sacrificing angular acceptance. This is achieved by combining an asymmetrically-cut, low order reflection with a symmetrically-cut, high order reflection in a nested configuration. This monochromator is being used as a beam conditioner for nuclear resonant scattering of synchrotron radiation to produce x-rays with (mu) eV-neV resolution in the hard x-ray regime.

A system has been designed for concentration of an intense parallel beam of X-rays from a synchrotron. The system has two stages. The first stage consists of an array of tapered capillaries which decrease the beam cross section from 2 X 2 mm to about .05 mm and increase the beam divergence to near the critical angle. The second stage has a special asymmetric shape which decreases the beam cross section to 0.001 mm (1 micrometer) and increases the beam divergence to about 10 degrees. Although the optics have been optimized for 10 Kev X-rays, they should give substantial benefit over a range of X-ray energies from 5 - 20 Kev. The intensity gain is calculated to be between 5 X 10³ and 10⁵ depending on the transmission losses. The design parameters and the current experience with transmission measurements on prototype components will be reviewed. Questions relating to beam heating and radiation damage will also be discussed.

Zone plates currently used in x-ray optics derive their focusing power from (a spatial variation of) the electronic refractive index--that is, from the collective effect of electronic x-ray- scattering amplitudes. Nuclei also scatter x rays, and resonant nuclear-scattering amplitudes, particularly those associated with Mossbauer fluorescence, can dominate the refractive index for x rays whose energies are very near the nuclear-resonance energy. A zone plate whose Fresnel zones are filled alternately with ⁵⁷Fe and ⁵⁶Fe (⁵⁷Fe has a nuclear resonance of natural width (Gamma) equals 4.8 nano-eV at 14.413 keV; ⁵⁶Fe has no such resonance) has a resonant focusing efficiency; it focuses only those x rays whose energies are within several (Gamma) of resonance. When followed by an absorbing screen with a small pin- hole, such a zone plate can function as a synchrotron-radiation monochromator with an energy resolution of a few parts of 10¹². The energy-dependent focusing efficiency and the resulting time-dependent response of a resonant zone plate are discussed.

At present beamline 3B1 in Synchrotron Radiation Lab. of Beijing Electron Position Collider has been set up for soft X-ray photolithography experiment. 3B1B beamline branched from beamline 3B1 operates at VUV-VIS for biological spectroscopic experiment. This paper describes design and fabrication on optical system of 3B1B. The features of optical system design is to adopt an off-axis paraboloid mirror which focuses light beam from synchrotron radiation source on entrance slit of Vm-562 vacuum monochromator and homogeneously circular spot appears on focal plane. An ellipsoidal mirror is used to focus spot on exit slit onto sample. It is very difficult to fabrication two aspherical mirror, it is 600 mm from axis, focal length f equals 315.7, dimension 40 X 100 mm², length of long axis of the ellipsoidal mirror is 1200 mm and that of short axis is 848.52 mm. Al+MgF₂ layer is coated on the surface mirror. We make use of special fabrication technology and testing method for mirrors and get satisfied with results. Figure error of two mirrors: diameter of circle of diffusion is less than 0.1 mm and surface roughness is less than 1 nm RMS. As it operates at 140 - 400 nm, incidence angle (theta) equals 45 degree(s), reflectivity of the mirror is better than 75%. These conditions meet requirements for biological spectroscopic experiments in the beamline.

Tapered glass capillaries are simple devices which have been used to concentrate x-rays. Micron-sized x-ray beams were produced using a variety of gradually tapered capillaries. Intensity gains ranging from 14 to 35 are reported using 6-keV synchrotron radiation. Data is presented demonstrating the potential of such devices as x-ray beam steering devices. In addition, a white-beam experiment is reported showing that tapered capillaries may be used as x-ray imaging components.

A submicron-diameter x-ray beam from a tapered glass capillary has been used to image metal stripes on a lithography sample consisting of a 1000 angstroms thick gold pattern on a silicon wafer substrate. By fitting a function to data obtained from transmission and fluorescence measurements as the edge of a gold stripe was scanned across the end of the capillary, the beam size leaving the tip of the capillary was determined to be 2000 angstroms. The maximum gain for this capillary is now shown to be 240 at 6 keV. An image of the gold pattern with submicron resolution was easily observed from transmission measurements as the sample was scanned in two dimensions. Using the same capillary, Laue diffraction was observed from a 500-micrometers -thick silicon wafer in a 10-second exposure corresponding to an illuminated volume of 15.7 micrometers ³. Laue patterns from significantly smaller volumes should be possible in the near future.