EP1422725A2 - Reflector for X-rays - Google Patents

Abstract

The reflector (5) has a non-circular arc shaped reflecting surface along a cross section, which extends in an XZ plane containing an X direction. Another non-circular arc shaped reflecting surface along another cross section, which extends in an YZ plane perpendicular to the X direction. The latter arc shaped reflecting surface defines focusing properties of the reflector within YZ plane. An Independent claim is also included for an X-ray analysis device.

Description

The invention relates to a reflector for X-rays, which along of a first cross-section in a plane containing an x-direction in the shape of a non-circular arc is curved (tangential curvature), the reflector also along a second cross section in a direction perpendicular to the x direction Plane is curved (sagittal curvature).

A generic X-ray mirror is for example from the DE 44 07 278 A1 has become known.

X-ray light, like visible light, is electromagnetic radiation. Due to the higher energy in the order of keV the Interaction of X-rays with matter, however, is significantly different than with visible light. In particular, there have been considerable difficulties effective optical components such as mirrors or lenses for To provide x-rays. The components realized so far are based primarily on Bragg diffraction and total reflection, both under grazing idea.

An X-ray mirror based on Bragg diffraction is in one plane Execution only to reflect a very small proportion of the incident, able to divergent X-rays because the Bragg condition is a requires comparatively sharp angle of incidence. To fix This problem became curved mirror surfaces and continued to be local variable level spacing proposed. The curvature of the The mirror surface and the plane spacing are along a first one Direction x, which is approximately the main direction of propagation of the X-rays (at grazing idea), changeable. The local radius of curvature is with the usual dimensions of X-ray analyzers in the range of meters and usually follows a parabolic or elliptical profile. It is manufacturing technology relatively easy to manufacture. To realize a changeable Layer spacing was used on a multi-layer mirror design. For this type of X-ray mirror, the name "Goebel mirror" established, cf. DE 44 07 278 A1.

The reflectivity of the Goebel mirror is limited by the fact that a No divergence of the beam perpendicular to the x-direction in the mirror plane can be sufficiently taken into account. A two-dimensional focus is due to a rotationally symmetrical design, i.e. a second, circular mirror curvature in the plane perpendicular to the x direction conceivable. The curvature of the mirror perpendicular to the x direction must be for typical dimensions of x-ray analysis devices with radii of curvature but are in the millimeter range. So far, however, one has not succeeded X-ray mirror with such a strong curvature with sufficient To manufacture accuracy. Reducing the Surface roughness and waviness of such a strongly curved mirror with sufficient precision. On the other hand, it is not yet acceptable Effort possible, layer thickness errors in the area of large radii of curvature (i.e. at the edge of the mirror) with common coating techniques (sputtering, Avoid molecular beam epitaxy, etc.) for multi-layer mirrors. This Coating errors reduce the reflectivity of the X-ray mirror for the desired x-ray wavelength and carry scattered radiation from others Wavelengths.

In order to still achieve two-dimensional focusing, two must be Goebel mirrors rotated approximately 90 ° to each other in Series are used, which entails considerable loss of intensity.

This represents another lack of rotationally symmetrical Göbel mirrors circular, ring-shaped beam profile of the mirrored X-rays out of focus. Either the sample or the detector are usually in focus, so either Detector or the sample is arranged in the region of the annular beam profile become. On the one hand, this brings with it loss of intensity, on the other hand it is Beam path of such an X-ray analysis device through the ring-shaped Beam profile inflexible.

There are also rotationally symmetrical total reflection mirrors with known two-dimensional focusing. However, total reflection levels are due to the lower light collecting capacity, the very low maximum angle of incidence and the associated Adjustment difficulties and the lack of monochromatization in the Practice an alternative only in exceptional cases.

In contrast, the object of the present invention is to design the X-ray mirrors and the beam profile of reflected X-rays flexibilize to facilitate the manufacture of x-ray mirrors and thereby at the same time high efficiency (i.e. high reflectivity and good focusing properties) of the X-ray mirrors ensure can.

This task is done in a surprisingly simple but effective way through a reflector for X-rays (X-ray mirror) of the entrance presented type solved, which is characterized in that the reflector along the second cross section also one of a circular arc has a different curvature.

The curvature along the second cross-section (sagittal curvature) is for the production of two-dimensionally focusing mirrors is particularly delicate. According to the invention, this second curvature can deviate from that Arc shape can be selected. In particular there are deviations that the curvature of the reflector along the second cross section and especially in Reduce the edge area of the reflector, especially in consideration. Then can Polishing operations that reflect the roughness or ripple of the reflector surface should reduce, be carried out much easier.

In addition, a deviation from the rotationally symmetrical shape opens up also new possibilities in the design of the beam profile of the reflected x-ray beam out of focus (focus). The circular ring shape out of focus can be abandoned. By appropriate design of the curvature of the invention Reflector along the second cross section, the beam shape Requirements of a special experiment. As alternative Beam shapes are, for example, an elliptical ring shape or a lenticular shape available. The beam shape can in particular the shape a sample to be examined or an X-ray detector or its Input gap can be adjusted.

The deviation from curvature along the second cross section opens also the possibility of coating defects in multi-layer mirrors tolerate without sacrificing the reactivity of the X-ray mirror to need (see below).

In an advantageous embodiment of the reflector according to the invention represents the curvature of the reflector along the second cross section Focusing properties of the reflector, particularly in the x direction vertical plane, a. The curvature of the reflector along the second Cross-section then determines the direction of the outgoing X-rays that diverge on incidence in the reflector plane perpendicular to the x direction. The focusing effect of the curvature along the second cross-section can be chosen in particular that the focal points of both curvatures of the reflector coincide, for example at the detector or at infinity for a parallel beam.

An embodiment of the invention is particularly advantageous Reflector in which the reflector focuses two-dimensionally or is parallelizing. This can create a high intensity in one outgoing X-ray beam are obtained, because on the invention Reflector is only a loss-causing reflection to the two-dimensional Focusing or parallelization of an X-ray beam necessary.

In a further advantageous embodiment, the reflector is like this configured that the reflector along the first cross section (tangential Curvature) is parabolic, hyperbolic or elliptically curved. The Parabolic shape is the basic shape of the Goebel mirror and allows one Parallelization of the outgoing X-ray (with respect to the Beam divergence on the reflector that reflects the mirror surface in the x direction sweeps). An elliptical shape allows the beam to be focused on a certain focal spot (again with respect to the one just mentioned Divergence).

The preferred embodiment of the reflector according to the invention is characterized in that the reflector has a periodically repeating sequence of layers of materials A, B, ... with different refractive index, the sum d = d _A + d _B + ... of the thicknesses d _A , d _B , ... of successive layers of materials A, B, ... changes continuously, in particular monotonically, along the x-direction. This embodiment thus largely represents a Goebel mirror, but it has a non-circular arc-shaped curvature along the second cross section. So far it has not been technically possible to produce Goebel mirrors with a rotationally symmetrical second curvature of sufficient quality. The above embodiment is significantly easier to produce than a rotationally symmetrical Goebel mirror, but has comparable X-ray optical properties: The change in the angle of incidence on the multilayer over the length of the X-ray mirror from front to back (in the x direction) is changed in the Bragg condition by adapting the Layer distance (plane distance) equalized to ensure good reflectivity for the X-rays of a certain wavelength over the entire length of the X-ray mirror. The focusing of the beam divergence perpendicular to the x-direction in the mirror plane is set by the curvature along the second cross-section deviating from a circular arc shape. In general, this deviation results in imperfect focusing. This may be desirable for certain applications and is therefore expressly part of the present invention.

The advantages of the invention come from a further development of these Embodiment but particularly well brought about by this is characterized in that the sum d is along the second Cross-section changes, especially by more than 2%. The change in the Sum d along the second cross section is almost inevitable Failure to coat heavily curved surfaces. in the Edge area of the reflector, the curvature is particularly strong and as a result, the layer thickness reached there at usual Coating process only a smaller thickness than on uncurved, flat spots. But if the layer thickness changes, the Bragg's equation continues to be fulfilled and therefore sufficient To ensure reactivity at a certain wavelength, the The angle of incidence of the radiation can be adjusted. But the angle of incidence is a function of the local curvature of the reflector. With knowledge of Dependence on the curvature of the coating thickness (e.g. by Model calculation, you detailed description, or experimental determination) can thus via a specific previous adjustment of the curvature of the Mirror the actual reflection and focus behavior of the finished Multi-layer reflector determined and thus adjusted.

An embodiment of this training is particularly advantageous, in which the reflector is characterized in that the curvature of the Reflector along the second cross section the change in sum d along the second cross-section with a comparison reflector a constant sum d and circular curvature along it second cross section with respect to the focusing and reflectivity properties of the reflector compensated. This configuration will realized an X-ray optical component, the properties of which correspond to the rotationally symmetrical Göbel mirror. A functional, Experimentally, rotationally symmetrical Goebel mirrors could not yet will be realized. However, this embodiment of the invention is easier to produce because the curvature is reduced along the second cross section and the inevitable layer thickness errors are tolerated can.

Another advantageous embodiment provides that the reflector along the second cross section with an elliptical curvature different lengths of the semiaxes or a parabolic Has curvature. The elliptical construction is particularly suitable for the focusing of the divergence of the radiation perpendicular to the x-axis in the Mirror plane; the parabolic shape favors the formation of a Parallel beam.

In an advantageous embodiment of the reflector according to the invention the reflector has a reflective surface of more than 2 mm, in particular at least 4 mm wide (measured perpendicular to the x direction) on. With conventional rotationally symmetrical Goebel mirrors, the Reflectivity for a certain wavelength towards the edge; in particular are reflective in the usual dimensions of an X-ray analysis device Widths limited to less than 2 mm. The reflector according to the invention has but high reactivity over much larger latitudes. This allows the reflected intensity in a first approximation proportional to the invention reflective surface can be increased.

Also within the scope of the present invention X-ray analyzer with an X-ray source, one to be analyzed Sample, an x-ray detector, beam-shaping and / or beam-limiting agents and an above inventive Reflector. The reflector according to the invention is particularly well received Applicable when used in an X-ray analyzer. The In addition to an X-ray tube, the X-ray source can also have a separate one Include monochromator. The sample can be stored on a goniometer his. The detector can be designed to dissolve energy or else integral event counting.

In a preferred embodiment of the invention X-ray analyzer hits X-rays on the reflector in one Angle of less than 5 ° to the x direction. Under these conditions Bragg diffraction is particularly effective, as with conventional X-rays in the Range of a few keV (e.g. Cu-Kα) the associated layer spacing is technologically easy to manufacture.

In another advantageous embodiment, the curvature of the Reflector is formed along the second cross section so that the Reflectivity of the reflector for the wavelength of that from the x-ray source generated radiation is maximum. This will reflect high Intensities and thus shorter measuring times in the X-ray analyzer achieved. In particular, different reflectors can also be used for specific ones X-ray wavelengths can be provided interchangeably.

An embodiment in which the reflector is on it is particularly advantageous X-rays incident on a punctiform area (focal spot), especially focused on the sample or on the X-ray detector. This are the most common applications for a beam path, in which the Count rate at the detector is maximized.

An embodiment of an inventive is also advantageous X-ray analyzer in which the reflector is made of incident on it X-rays an x-ray with a certain Beam divergence, in particular a parallel beam, is generated. With parallels X-rays can illuminate samples particularly evenly and a similar beam profile can be seen on the sample and on the detector can be set.

Further advantages of the invention result from the description and the Drawing. Likewise, the above and the others executed features according to the invention individually for themselves or to several can be used in any combination. The shown and The described embodiments are not to be considered as a conclusive list understand, but rather have exemplary character for the Description of the invention.

Fig. 1a

ein erfindungsgemäßes Röntgenanalysegerät mit schematischer Darstellung einer Strahldivergenz, die einen erfindungsgemäßen Reflektor in x-Richtung überstreicht;

Fig. 1b

das Röntgenanalysegerät von Fig. 1a mit schematischer Darstellung einer Strahldivergenz, die den Reflektor in Spiegelebene senkrecht zur x-Richtung überstreicht;

Fig. 2a

den erfindungsgemäßen Reflektor von Fig. 1a sowie einen ersten Querschnitt in einer die x-Richtung enthaltenden Ebene;

Fig. 2b

den erfindungsgemäßen Reflektor von Fig. 1a sowie einen zweiten Querschnitt in einer zur x-Richtung senkrechten Ebene;

Fig. 3

einen Querschnitt durch einen rotationssymmetrischen Reflektor (Stand der Technik);

Fig. 4

einen Querschnitt durch einen erfindungsgemäßen, nicht-rotationssymmetrischen Reflektor;

Fig. 5

den Aufbau eines Einkristalldiffraktometers für die Proteinkristallographie nach dem Stand der Technik;

Fig. 6

das Strahlbild eines rotationssymmetrischen fokussierenden Reflektors im Bildfokus und außerhalb des Bildfokus (Stand der Technik);

Fig. 7

das Strahlbild eines Segments eines zweidimensional fokussierenden Reflektors im Bildfokus und vor dem Bildfokus (Stand der Technik);

Fig. 8

einen Ausschnitt aus einem rotationsellipsoidförmigen fokussierenden Reflektor (Stand der Technik)

Fig. 9

den Höhenverlauf des Reflektors von Fig. 8 entlang x;

Fig. 10

den Höhenverlauf des Reflektors von Fig. 8 entlang y;

Fig. 11

den lokalen Neigungswinkel der Reflektoroberfläche des Reflektors von Fig. 8 gegen die y-Achse bei x=90mm;

Fig. 12

einen Aufbau einer herkömmlichen Beschichtungsvorrichtung zum Beschichten eines Reflektors ohne Vermeidung von Beschichtungsfehlern (Stand der Technik);

Fig. 13

den Verlauf der relativen Beschichtungsdicke (Beschichtungsfehler) an der Reflektoroberfläche des Reflektors von Fig. 8 in y-Richtung bei x=90mm;

Fig. 14a

die Reflektivität über die Fläche eines rotationsellipsoidförmigen Reflektors mit Abmessungen 60 x 4 mm unter Annahme eines cos(β)-Beschichtungsfehlers für Cu-Kα-Strahlung;

Fig. 14b

die Reflektivität über die Fläche eines rotationsellipsoidförmigen Reflektors mit Abmessungen 60 x 4 mm unter Annahme eines cos(β)-Beschichtungsfehlers für Cu-Kβ-Strahlung;

Fig. 15

einen Aufbau einer Beschichtungsvorrichtung zum homogenen Beschichten eines Reflektors;

Fig. 16

erfindungsgemäße Kompensationskurve eines cos(β)-Beschichtungsfehlers durch ein nicht-rotationssymmetrisches Ellipsoid.

The invention is illustrated in the drawing and is explained in more detail using exemplary embodiments. Show it:

Fig. 1a

an X-ray analysis device according to the invention with a schematic representation of a beam divergence which sweeps over a reflector according to the invention in the x direction;

Fig. 1b

1a with a schematic representation of a beam divergence which sweeps over the reflector in the mirror plane perpendicular to the x direction;

Fig. 2a

1a and a first cross section in a plane containing the x direction;

Fig. 2b

1a and a second cross section in a plane perpendicular to the x direction;

Fig. 3

a cross section through a rotationally symmetrical reflector (prior art);

Fig. 4

a cross section through a non-rotationally symmetrical reflector according to the invention;

Fig. 5

the construction of a single crystal diffractometer for protein crystallography according to the prior art;

Fig. 6

the beam image of a rotationally symmetrical focusing reflector in the image focus and outside the image focus (prior art);

Fig. 7

the beam image of a segment of a two-dimensionally focusing reflector in the image focus and in front of the image focus (prior art);

Fig. 8

a section of an ellipsoidal-shaped focusing reflector (prior art)

Fig. 9

the course of the height of the reflector from FIG. 8 along x;

Fig. 10

the course of the height of the reflector from FIG. 8 along y;

Fig. 11

the local angle of inclination of the reflector surface of the reflector of Figure 8 against the y axis at x = 90mm.

Fig. 12

a structure of a conventional coating device for coating a reflector without avoiding coating errors (prior art);

Fig. 13

the course of the relative coating thickness (coating error) on the reflector surface of the reflector from FIG. 8 in the y direction at x = 90 mm;

14a

the reflectivity over the surface of an ellipsoidal-shaped reflector with dimensions 60 x 4 mm, assuming a cos (β) coating error for Cu-Kα radiation;

14b

the reflectivity over the surface of an ellipsoidal-shaped reflector with dimensions 60 x 4 mm, assuming a cos (β) coating error for Cu-Kβ radiation;

Fig. 15

a structure of a coating device for homogeneous coating of a reflector;

Fig. 16

Compensation curve according to the invention for a cos (β) coating defect due to a non-rotationally symmetrical ellipsoid.

1 shows the structure of an X-ray analysis device according to the invention in a schematic representation. X-ray radiation emanates from the X-ray source 1. Two beams 2 and 3 of this x-ray radiation are shown in FIG. 1a. Both beams 2, 3 pass through a pinhole 4 and hit the reflecting surface of the reflector 5 according to the invention. An orthogonal coordinate system X, Y, Z is coupled to the reflector 5. The reflector is a multi-layer gradient mirror. The reflective surface is formed by a periodic sequence in the Z direction of at least two layers of materials A, B with different refractive index for the X-rays used. The respective layers therefore extend approximately in adjacent XY planes. The reflecting surface of the reflector 5 is curved in two dimensions (see FIGS. 2a and 2b). According to the invention, both curvatures are not circular arcs.

The beams 2, 3 are reflected on the reflector 5, penetrate the Sample 6 and are registered in the X-ray detector 7.

The beams 2, 3 have a divergence 8 in the XZ plane of typically 0.2 - 2 °. The angle of incidence 9 of the two beams 2, 3 is about 0.5 - 2.5 ° against the X direction or the X 'direction (the Angle of incidence 9 is shown in FIG. 1a and also in FIG. 1b shown exaggerated). The X direction is the main direction of extension of the Reflector 5. Apart from the angle of incidence 9, the direction of incidence is correct the X-ray radiation on the reflector 5 corresponds to the X direction.

The divergence 8 of the incident X-rays in the XZ plane is determined by the curvature of the reflector along its first cross section (tangential Curvature) in an XZ plane, i.e. a plane containing the x direction, focused (see Fig. 2a). The curvature of the reflector along the first Cross-section is parabolic in Fig. 1a.

Fig. 1b shows the same X-ray analyzer as Fig. 1a, but with two other beams 10 and 11. Both beams have a divergence 12 in the YZ plane. The order of magnitude of this divergence 12 is approximately 1-2 °. The beams 10, 11 are reflected on the surface of the reflector 5, penetrate the sample 6 and are registered in the detector 7.

The divergence 12 of the incident X-rays in the YZ plane becomes by the curvature of the reflector along a second cross section (sagittal curvature) in a YZ plane, i.e. the one perpendicular to the x direction Level, focused (see Fig. 2b). Unlike the well-known Goebel mirror has the illustrated reflector 5 according to the invention along the second Cross-section a non-circular arc, namely approximately one elliptical curvature.

The curvature of the reflector 5 is illustrated in FIGS. 2a and 2b . Both figures show the reflector 5 of FIGS. 1a / b enlarged. The intersection line 13 of the reflecting surface of the reflector 5 with the XZ plane (which contains the X direction) reveals the curvature of the reflector in a first dimension. In Fig. 2a this curvature can be seen as parabolic. This first curvature represents the curvature of the reflector along the first cross section.

The intersection line 14 of the reflective surface of the reflector 5 with the YZ plane reveals the curvature of the reflector in a second dimension. This curvature can be seen as elliptical in FIG. 2b. This second Curvature represents the curvature of the reflector along the second Cross-section and is not circular arc shaped according to the invention. in the illustrated case, and generally also advantageous for the invention, is the Reflector surface mirror-symmetrical with respect to a central XZ plane designed to reflect a uniformly illuminated x-ray beam to obtain.

In the following, the device according to the invention for conditioning X-rays through two-dimensionally curved X-ray reflectors, especially multi-layer X-ray reflectors, with non-rotationally symmetrical ones Shape explained in detail.

Find reflectors with a multilayer ('multilayer') for some years use for conditioning X-rays in various X-ray analysis instruments. These multilayers exist typically from tens to hundreds alternating Single layers made of two or more materials, with single layer thicknesses of typically 1 - 20 nm. With these multilayers, X-rays are incident according to Bragg's equation through the effect of diffraction redirected and monochromatized. The reflectivity of this multilayer can be used for X-rays can be very high; Reflectivities of up to 90% were found theoretically predicted and in recent years by continuous Improvements in the coating technologies used in manufacturing also achieved experimentally ('X-ray mirror'). With real, spatial extensive X-ray sources (in contrast to non-existent, ideal Point sources) the reflectivities are reduced depending on the source size typically 30-70%. For use in the area of hard X-rays (Wavelengths typically 0.05 - 0.25 nm), the deflection angles are typical in the range between 0.5 - 2.5 degrees, so there are applications in the area the grazing idea.

Significant improvements of such X-ray reflectors have been made, for example, by US Pat. No. 6,226,349 and [M. Schuster, H. Göbel, L. Brügemann, D. Bahr, F. Burgäzy, C. Michaelsen, M. Störmer, P. Ricardo, R. Dietsch, T. Holz, and H. Mai, "Laterally graded multilayer optics for x -ray analysis ", Proc. SPIE 3767 , pp. 183-198, 1999] by the reflectors being curved in one dimension (parabolic, elliptical, etc.). The requirements for the shape accuracy of these reflectors are high, and are well below 1 micron in the range. In order to obtain high reflectivity for such reflectors at all points on the reflector, the multilayer coatings must vary in a very defined manner over the surface of the reflector, according to the information, for example, from US Pat. No. 6,226,349 and [Veröff. Cobbler like this]. The requirements for the precision of the coating of such reflectors are extremely high, and typically amount to 1-3% of the individual layer thicknesses. These tolerances result from the widths of the multilayer Bragg reflexes, which are typically in the range 1 - 3% of the Bragg angle. This results in coating requirements that are typically in the range of a few ten picometers. Despite these extreme requirements, the manufacture of such reflectors has succeeded in the past few years using various methods, and these reflectors have been a commercially available product for several years.

Since these reflectors are operated at small angles of incidence, they are Deviations in shape from a flat shape are typically small, and lie in the Range of a few tens of micrometers, the radii of curvature are typically included a few meters, macroscopically speaking, the reflectors are in essentially flat. For coating this macroscopically flat There are therefore no further reflectors compared to flat reflectors Problems due to the curvature of the reflectors. From the perspective of the coating are these reflectors i.w. plan.

Two-dimensionally curved, rotationally symmetrical reflectors (Rotation ellipsoid, rotation paraboloid etc. or segments of these shapes), Even coated with multilayers are common for X-rays have been proposed, e.g. US 4,525,853, US 4,951,304, US 5,222,113 however, were never realized. The reasons for this are the enormous technical Problems with the coating (tangentially varying according to US 6,226,349, and at the same time extremely homogeneous (1 - 3%) in the transverse direction in which the optics is now also curved). This is essentially due to the fact that this Reflectors essentially flat again tangentially (radii of curvature in the Meter range), perpendicular to it (sagittal) but must be strongly curved with Radii of curvature typically in the range of just a few millimeters. This is again that the reflectors are operated at small angles of incidence. This results in, in addition to the need for a tangential extreme precise coating (corresponding to US 6,226,349), in the transverse direction considerable angle of inclination and resulting coating errors. The Reflectors are no longer flat, but are macroscopically curved. That I in the coating processes typically used, the layer thicknesses change with the angle of inclination to the coating source is the additional one Demand for a homogeneous layer thickness in the transverse direction, again in the area a few ten picometers, an additional technological challenge. The required coating has not been achieved so far.

Therefore, two-dimensional collimating or focusing multilayer X-ray reflectors have so far only been in accordance with US 6,014,423 and US 6,014,099 and earlier work [M. Montel, X-ray Microscopy and Microradiography , Academic Press, New York, pp. 177-185, 1957; VE Cosslett and WC Nixon, X-Ray Microscopy, Cambridge, At The University Press, p. 108 ff, 1960; Encyclopedia of Physics, ed. S. Flügge, Vol. XXX : X-Rays, Springer Berlin, p. 325 ff, 1957; Kirkpatrick-Baez, see e.g. 1 in US Pat. No. 6,041,099] by the combination of two macroscopically iw flat reflectors, that is to say by double reflection. Since at least two reflectors have to be used here and these have to be aligned very precisely with one another, this results in increased costs and an increased adjustment effort. Added to this is the loss of intensity when using two reflectors. Since even the best multilayer reflectors lose their effectiveness with increasing expansion of the sources, particularly when used with extended X-ray sources (eg rotating anodes), intensity losses of 50% per reflection are quite normal. Nevertheless, these reflectors are the only two-dimensionally collimating or focusing multilayer X-ray reflectors according to the prior art.

Two-dimensional collimating or focusing, rotationally symmetrical X-ray reflectors with sagittal radii of curvature in the millimeter range exist So far, it has only been used as a total reflection mirror (e.g. WO 0138861, or MICROMIRROR TM Bede Scientific). Here are very few Coating requirements (only a single layer is required, e.g. Gold, and the layer only has to be sufficiently thick,> approx. 30 nm, one homogeneous layer thickness is not required), and compared to a multilayer reflector much lower requirements for the micro roughness of the To meet the reflector (for total reflection approx. 1 nm, multilayer mirror required in contrast, according to US Pat. No. 6,226,349, a roughness <0.3 nm). However, total reflectors have several compared to multilayer reflectors essential disadvantages: the even smaller angle of incidence (about three times smaller) and the resulting lower light collecting capacity, and the Lack of monochromatizing effects from totally reflecting mirrors. Total reflectors have no monochromatizing properties, but only suppress high-energy X-rays for which the Total reflection angle is exceeded for a given geometry.

For these reasons, it is extremely desirable to use improved methods and Process for the production of two-dimensionally collimating or focussing to provide multilayer coated X-ray reflectors.

This is achieved according to the invention in that non-rotationally symmetrical, two-dimensionally curved, multilayer coated Body used. The benefits that result from abandoning the constraint of the rotational symmetry are not obvious, and are therefore described in the following examples.

First of all, the change from a rotationally symmetrical to a non-rotationally symmetrical reflector has a disadvantage. This is shown in FIGS. 3 and 4 using the example of a focusing reflector. While in the case of rotationally symmetrical reflectors 30 (FIG. 3), the cross section is circular and all rays 31 are reflected perpendicularly to the tangent at a point 32, this is not the case with non-rotationally symmetrical reflectors 40 (FIG. 4). Non-rotationally symmetrical reflectors therefore result in a loss of focus. However, the free choice of cross-section opens up some additional options, as exemplified below. It is important (as calculations show) that the loss of focus only occurs horizontally (in width), but not vertically (in height). This is due to the fact that the magnification ratio (source size to image size) of the reflectors under consideration is practically independent of the choice of the cross-sectional shape of the reflector. This surprising property is ultimately due to the high eccentricity of the reflectors relevant here (as described below).

A typical application (a so-called single crystal diffractometer) is shown in FIG . The x-ray light 52 emitted from an x-ray source 51 (with a 200 μm pinhole) is focused on the two-dimensional detector 54 with the aid of a rotationally symmetrical reflector 53 (for example MICROMIRROR). Due to the finite extent of the x-ray source (for example 0.1 mm diameter), the beam image in image focus 61, see FIG. 6 , is also typically a few 0.1 mm in size. The sample 55 with a diameter of typically 0.5 mm is typically located 10 cm in front of the detector 54. However, the beam pattern 62 is ring-shaped there. This means that the sample 54 is not optimally illuminated. Similarly, it is disadvantageous if the sample is placed in focus because the scatter pattern in the detector is then not punctiform. The basically annular beam profile 62 outside the image focus is generally disadvantageous.

It is therefore sufficient, or even advantageous, to use only a part (only a segment) of the entire reflector for such applications. As shown in FIG. 7 , for such a section of the reflector, the beam image both in focus 71 (detector) and outside focus 72 (sample) is of similar size. With a suitable choice of the reflector and the size of the reflector cutout, beam dimensions are achieved which are ideal for the application.

An ellipsoidal reflector cutout 81 according to FIG. 8 is specified in more detail below by way of example. The shape of the ellipsoid 82 is described by ( x - a ) 2 a 2 + y 2 b 2 + z 2 c 2 = 1

For the case b = c , there is a rotationally symmetrical ellipsoid with a circular cross section (prior art). For b ≠ c , a non-rotationally symmetrical ellipsoid with an elliptical cross section results (however, according to the invention, any cross-sectional shapes are possible). Typical values for a, b and c are a = 250 mm, b = 5 mm, and c = 5 mm. This results in a distance between the source and image focus of 2a = 500 mm and a maximum diameter of the reflector 2b = 10 mm. As already described above, the need for the short radius of curvature in the yz plane results from the constraint of the small angle of incidence.

The corresponding height profiles along x and y are shown in FIGS. 9 and 10 for a 4 mm wide reflector cutout. The curves along x according to FIG. 9 are generally flat and have a depth of fall (in the z direction) of a few tens of micrometers over a length of a few tens of millimeters, that is to say they have a large radius of curvature of typically a few meters. The curves along y according to FIG. 10 are macroscopically curved and have a depth of fall of a few hundred micrometers over a width of 4 mm, that is to say they have a small radius of curvature in the range of a few millimeters. As shown in FIG. 11 , this strong curvature in the yz plane results in a considerable edge inclination of the reflector with respect to the horizontal, on the edge of the 4 mm wide reflector there are inclination angles β of approximately 30 degrees. This edge tendency leads to considerable problems in the coating, which must be homogeneous in the yz plane for a rotationally symmetrical body (in addition to the layer thickness gradient along x already mentioned according to the prior art and the enormously high accuracy requirements described there). The coating processes used for the production of X-ray reflectors, such as "sputtering" according to US Pat. No. 6,226,349, generally use coating sources with a more or less directed material beam. This means that when coating inclined or tilted surfaces, less material per unit area condenses according to the angle of inclination β than in the case of frontal coating ( FIG. 12 , with coating source 120, material jet 121, mirror substrate 122 and angle of inclination β). Sputtering, for example, gives an approximate layer thickness distribution that varies with cos (β), where β is defined according to β = arctan ( dz / dy ) (more generally, a dependency with (cos β) ^{n is} observed, where n depends on details of the coating process used depends; in the following a process with n = 1 is assumed without restriction of generality). In FIG. 13 it is shown that in the case of such a coating defect the reflector only fulfills the above-mentioned tolerable layer thickness errors of <2% over a width of less than 2 mm.

Detailed investigations with Monte Carlo methods (ray tracing), see Fig. 14 (reflectivity for two wavelengths, Cu-Kα and Cu-Kβ) over the area of a reflector of 60 x 4 mm ² assuming a cos (β) Coating error; bright dots indicate high reflectivity), confirm this result. In addition, such studies show that the reflector not only no longer reflects the desired X-ray wavelength in the edge areas (e.g. Cu Kα, Fig. 14a ), but also undesirably begins to reflect a different wavelength in these edge areas due to the decreasing layer thicknesses (e.g. Cu Kβ, Fig. 14b ). In addition to the intensity, the reflector also loses its monochromatizing effect.

For the coating of such a reflector it is therefore necessary additional equipment measures for homogenizing the layer along the strongly curved surface. Two ways to Homogenization of the layer is shown in FIG. 15 (coating source 151, Material flow 152) outlined. For example, by moving one Aperture 153, or by suitable swivel, pendulum or other Rotations of the mirror substrate 154, or a combination thereof Measures ensure that the layer is along the highly curved Surface becomes homogeneous. However, it is still necessary along the x direction in an extremely precise manner as described above to maintain the necessary layer thickness gradient. The fulfillment of this Condition in the i.w. flat reflectors according to the prior art already involves considerable expenditure on equipment (see e.g. DE 19701419), since they are usually next to at least one rotary movement or aperture shift also measures to stabilize the Temperature or other relevant parameters without affecting the usually requires high quality of the vacuum. For the controlled Coating of strongly curved surfaces is additional as described at least one further rotary movement or diaphragm movement is required.

The additional equipment required to set all of these conditions of the coating with a precision in the range of a few ten picometers a three-dimensionally curved surface is, therefore, enormously high as far as we know it has not yet been realized.

The solution according to the invention eliminates the need for any Modification of the equipment previously used for coating. Coating systems, e.g. in Fig. 12 of US 6,226,349 Manufacture of X-ray reflectors that can be used without any Changes also for the manufacture of the reflectors according to the invention be used. According to the solution according to the invention, the Semi-axis b chosen such that the coating errors described above can be perfectly compensated for abnormal incidence. This is the following described in more detail.

The ellipsoid of revolution is now preferably displayed in cylindrical coordinates: ( x - a ) 2 a 2 + r 2 b 2 = 1 with z = r · cosα and y = r · sinα.

So that a ellipsoid of revolution reflects optimally, the following must apply to the coating thickness d: d (α) = const.

f ist der Abstand zwischen Quellfokus und dem betrachteten Spiegelsegment, f' ist der Abstand zwischen dem betrachteten Spiegelsegment und dem Bildfokus. Aufgrund der hohen Exzentrizität (a>>b,c) der hier betrachteten Reflektoren gilt f ≈ x und f' ≈ 2a-x. δ ist der Dispersionskoeffizient der verwendeten Vielfachschicht (siehe z.B. US 6,226,349).If a coating error occurs, it can be corrected by varying b with α. The ellipsoid of revolution then becomes the general, non-rotationally symmetrical ellipsoid ( x - a ) 2 a 2 + r 2 b 2 (Α) = 1. b (α) becomes d ( f , α) = λλλ λ. b α , f · f ' Second b 2 α -δ. f , f ' calculated [publ. Cobbler like this]. You get

f is the distance between the source focus and the mirror segment under consideration, f 'is the distance between the mirror segment under consideration and the image focus. Due to the high eccentricity ( a >> b, c ) of the reflectors considered here, f ≈ x and f '≈ 2 a - x . δ is the dispersion coefficient of the multilayer used (see, for example, US 6,226,349).

beschreibbar.If, for example, the non-uniformity of the coating can now be described with d ( f , α) = d ₀ ( f ) · cosβ with β = arctan dz / dy , the angle dependence of the ellipse half-axis b is given by

writable.

The ellipsoid equation then changes to

die nach cos β aufgelöst

ergibt.1- ( x - a ) ² / a ² = r ₀ ² / b ₀ ^{2 can be} set for further analysis. The equation then results

which resolved to cos β

results.

y_{i +1} = y_i + Δy

A numerical solution is recommended for determining the cross-sectional shape z = f ( y ) - with the initial conditions β (0) = 0 and z (0) = - r ₀ . The calculation rule is

y _{i +1} = y _i + Δ y

Refined numerical solutions using known methods are possible. ray However, tracing simulations show that this solution is sufficient Accuracy is.

The cross-sectional profile thus calculated is shown in FIG. 16 . Compared to the rotationally symmetrical shape (b = c = 5 mm), the shape described here is flatter and corresponds in good approximation to an ellipsoid with b = 6.4 mm and c = 5 mm. Ray tracing calculations confirm that an ellipsoid modified in this way reflects the desired X-ray line over the entire cross section despite the coating error, in contrast to FIG. 14a without correction of the coating error. The desired monochromatizing effect is also completely retained, in contrast to FIG. 14b without correction. In addition, the flatter shape of the solution according to the invention has only approximately half the edge slope as the rotationally symmetrical ellipsoid. It is therefore to be expected that the coating problems as well as the manufacturing problems of the curved shape with the required low roughness will additionally be significantly reduced. The reflectors according to the invention are thus easier and cheaper to manufacture.

Analogously to the procedure described above, a non-rotationally symmetrical paraboloid can be calculated, which should now not focus the beam as described above, but should parallelize it. The paraboloid of revolution with the parabola parameter p is preferably represented in cylindrical coordinates: r 2 = 2 p · x with z = r · cosα and y = r · sinα.

So that a paraboloid of revolution reflects optimally, the following must again apply to the coating thickness d : d (α) = const.

Ist jetzt beispielsweise die Ungleichmäßigkeit der Beschichtung wieder mit d(f, α) = d ₀(f)· cosβ mit β = arctan dz / dy beschreibbar, so ist die Winkelabhängigkeit des Parabelparameters p durch

beschreibbar.If a coating error occurs, it can be corrected by varying p with α. The paraboloid of revolution then becomes the general, non-rotationally symmetrical paraboloid r 2 = 2 · p (Α) · x , p (α) becomes d ( f , α) = λ. 2 · p α · f 2 · p α -2 · δ · f calculated [publ. Cobbler like this]. You get

If, for example, the non-uniformity of the coating can now be described again with d ( f , α) = d ₀ ( f ) · cosβ with β = arctan dz / dy , the angle dependency of the parabola parameter p is complete

writable.

The paraboloid equation then changes to

die nach cos β aufgelöst cosβ = 1 d 0 f · λ·2·r·p 0·r 0·f 2· r·p 0-2·δ·f·r 0 ergibt.For further analysis, x = r ₀ ² ( x ) / 2 · p _{0 can be} set. The equation then results

which resolved to cos β cosβ = 1 d 0 f · λ · 2 · r · p 0 · r 0 · f 2 · r · p 0 -2 · δ · f · r 0 results.

A numerical solution is again recommended for determining the cross-sectional shape z = f ( y ) - with the initial conditions β (0) = 0 and z (0) = - r ₀ .

yi +1 = y i + Δy

The calculation rule is

y i +1 = y i + Δ y

Refined numerical solutions using known methods are possible. ray However, tracing simulations show that the solution of is sufficient accuracy.

The two procedures described above are only to be understood as examples, and analogous procedures are possible for other coating defects (e.g. parabolic, (cosβ) ⁿ ) and other reflector shapes (e.g. spherical, hyperboloid, ...).

The curved reflector substrates can, as in US Pat. No. 6,226,349, per se known way e.g. by grinding, polishing and lapping solid Made of quartz, Zerodur, glass, or other materials become. Roughness below 0.1 nm (0.3 nm is perfect for multilayers) and curvature errors below 5 µrad (below 25 µrad you already get a lot good mirrors) were in the reflectors according to US 6,226,349 by such Procedure routinely achieved. With these values are perfect Beam properties have been achieved. Other techniques for shaping the Reflector substrates are bending techniques [e.g. DE 19935513] or Impression / replica techniques [US 4,525,853 claim 12].

a) Die Herstellung der Form wird einfacher, da man flachere Formen mit geringeren Krümmungen und Randwinkeln verwenden kann. Die flachere Form erleichtert auch das Polieren auf die niedrigere Rauhigkeit.

b) Man kann durch die Wahl der Querschnittsform einen weiteren, günstigen Einfluss auf die Strahleigenschaften (Strahlabmessungen, Divergenz) nehmen, z.B. einen breiteren Strahl erzeugen, je nach Anwendung. So ist es z.B. (anders als bei der Einkristalldiffraktometrie) bei der Bestimmung von mechanischen Spannungen oder Texturen von Werkstoffen mit röntgendiffraktometrischen Methoden durchaus erwünscht, eine größere Probenfläche zu beleuchten. Durch die Wahl eines nicht-rotationssymmetrischen Reflektors hat man eine breitere Auswahl von anwendungsoptimierten Optiken zur Verfügung, man hat im Design der Optik eine größere Freiheit. Speziell für Multilayer-Röntgenspiegel gilt außerdem:

c) Beschichtungsfehler in Querrichtung können durch die (freie!) Wahl der Querschnittsform des Körpers in dieser Richtung vollständig kompensiert werden. Die Beschichtung wird dann "sehr" einfach, oder erstmals möglich, mit denselben Techniken die zurzeit für die i.w. nur flach gekrümmten Optiken verwendet werden.

d) Man bekommt (wesentlich) mehr Intensität, da man im Gegensatz zum Stand der Technik nur eine Reflektion benötigt wird (Intensitätsverlust pro Reflektion ca. 50 %), und da man eine größere Spiegelfläche verwenden kann. Bei den Reflektoren nach dem Stand der Technik wird der Reflektor auf nur ca. 1 mm Breite verwendet. Demgegenüber wurde hier bereits ein 4 mm breiter Reflektor beschrieben (ohne Einschränkung der Allgemeinheit). Zusammen kann man hier also schon einen Intensitätsgewinn um einen Faktor 8 erwarten.

e) Man braucht nur einen Spiegel, bei den Optiken gemäß dem Stand der Technik braucht man 2 Spiegel (Kostenfaktor).

f) Der Reflektor ist wesentlich einfacher zu justieren als eine Kirkpatrick-Baez-Anordnung nach dem Stand der Technik.

The advantages of the teaching according to the invention can be summarized as follows:

a) The production of the shape is easier because you can use flatter shapes with fewer curvatures and contact angles. The flatter shape also facilitates polishing to the lower roughness.

b) By choosing the cross-sectional shape, a further, favorable influence on the beam properties (beam dimensions, divergence) can be exerted, for example generating a wider beam, depending on the application. For example (unlike single crystal diffractometry) when determining mechanical stresses or textures of materials with X-ray diffractometric methods it is absolutely desirable to illuminate a larger sample area. By choosing a non-rotationally symmetrical reflector, you have a wider choice of application-optimized optics, you have greater freedom in the design of the optics. The following also applies specifically to multilayer X-ray mirrors:

c) Coating errors in the transverse direction can be completely compensated for by the (free!) choice of the cross-sectional shape of the body in this direction. The coating then becomes "very" simple, or is possible for the first time, using the same techniques that are currently used for the mostly flat curved optics.

d) You get (much) more intensity, because in contrast to the prior art, only one reflection is required (loss of intensity per reflection approx. 50%), and because you can use a larger mirror surface. In the case of the reflectors according to the prior art, the reflector is used only about 1 mm wide. In contrast, a 4 mm wide reflector has already been described here (without restricting generality). Together you can expect an increase in intensity by a factor of 8.

e) You only need one mirror, with the optics according to the state of the art you need 2 mirrors (cost factor).

f) The reflector is much easier to adjust than a Kirkpatrick-Baez arrangement according to the prior art.

Because of the particularly advantageous embodiment of the invention Reflector as a Goebel mirror with a non-rotationally symmetrical curvature transverse to the x direction (which is approximately the main direction of incidence of the X-ray radiation corresponds) to the design of a such embodiment or an associated X-ray analysis device in Be explained in detail.

• einer Röntgenstrahlung emittierenden Quelle,
• einer zu analysierenden Probe,
• einem auf Röntgenstrahlung ansprechenden Detektor,
• strahlformenden und/oder strahlbegrenzenden Mitteln, und
• einem gekrümmten Vielschicht-Bragg-Reflektor, der im Strahlgang zwischen der Quelle und der Probe angeordnet ist und eine sich periodisch wiederholenden Folge von Schichten umfasst, wobei eine Periode aus mindestens zwei Einzelschichten A, B besteht, die unterschiedliche Brechungsindex-Dekremente δ_A ≠ δ_B und die Dicken d_A und d_B besitzen,
• wobei die Periodendicke, also die Summe d = d_A + d_B +... der Einzelschichten A, B, ... einer Periode entlang einer x-Richtung sich stetig ändert, und
• wobei der Reflektor derart gekrümmt ist, dass er eine Teilfläche eines Paraboloids oder Ellipsoids bildet, in dessen Brennlinie bzw. Brennpunkt die Quelle oder ein Bild der Quelle liegt,
• wobei das Paraboloid oder Ellipsoid entlang eines Querschnitts in einer Ebene senkrecht zur x-Richtung nicht-kreisbogenförmig gekrümmt ist, d.h. das Paraboloid bzw. Ellipsoid ist nicht ein Rotationsparaboloid bzw. ellipsoid, sondern ein nicht-rotationssymmetrisches Paraboloid bzw. Ellipsoid.

The x-ray analyzer according to the invention which is preferred in this way is equipped with

• an X-ray emitting source,
• a sample to be analyzed,
• a detector responsive to x-rays,
• beam-shaping and / or beam-limiting agents, and
• a curved multilayer Bragg reflector, which is arranged in the beam path between the source and the sample and comprises a periodically repeating sequence of layers, one period consisting of at least two individual layers A, B, which have different refractive index decrements δ _A ≠ δ _B and have the thicknesses d _A and d _B ,
• where the period thickness, i.e. the sum d = d _A + d _B + ... of the individual layers A, B, ... of a period along an x-direction changes continuously, and
• the reflector being curved such that it forms a partial surface of a paraboloid or ellipsoid, in the focal line or focal point of which the source or an image of the source lies,
• wherein the paraboloid or ellipsoid is not curved in a circular arc along a cross section in a plane perpendicular to the x-direction, ie the paraboloid or ellipsoid is not a rotational paraboloid or ellipsoid, but a non-rotationally symmetrical paraboloid or ellipsoid.

• dass die Schichten des Reflektors direkt auf einer konkav gekrümmten Oberfläche eines paraboloidförmig ausgehöhlten Substrats aufgedampft, aufgesputtert oder aufgewachsen sind, wobei die Krümmung der konkaven Substratoberfläche in einer xz-Ebene der Formel z² = 2px folgt mit 0,02 mm < p < 0,5 mm, vorzugsweise p ≈ 0,1 mm;
• dass die dem Reflektor zugewandte konkave Substratoberfläche eine maximal zulässige Formabweichung von Δp = 2px ·ΔΘ_R aufweist, wobei ΔΘ_R die Halbwertsbreite des Bragg-Reflexes des Reflektors ist, und im Bereich 0,01° < ΔΘ_R < 0,5°, vorzugsweise 0,02° < ΔΘ_R < 0,20° liegt,
• dass die dem Reflektor zugewandte konkave Substratoberfläche eine maximale zulässige Welligkeit von Δz / Δx = 1 / 2 ΔΘ_R aufweist,
• dass die dem Reflektor zugewandte konkave Substratoberfläche eine maximal zulässige Rauhigkeit von Δz = d / 2π, vorzugsweise Δz ≤ 0,3 nm aufweist,
• dass die Röntgenstrahlung unter einem Einfallswinkel 0° ≤ Θ ≤ 5° auf die gekrümmte Oberfläche des Reflektors trifft,
• dass sich die Periodendicke d derart entlang der x-Richtung ändert, dass die Röntgenstrahlung einer bestimmten Wellenlänge λ einer punktförmigen Röntgenquelle unabhängig vom Auftreffpunkt (x, z) auf dem Reflektor stets Bragg-Reflexion erfährt, indem die Periodendicke d zur Paraboloidöffnung hin in x-Richtung gemäß d = λ / 2 1 / (1-δ/sin² Θ)sin Θ und Θ = arc cot 2px p zunimmt, wobei δ das Dekrement des mittleren Brechungsindex des Vielschicht-Bragg-Reflektors ist,
• dass die Abweichung Δd/Δx der Periodendicke d an jedem Punkt des Vielschicht-Bragg-Reflektors entlang der x-Richtung kleiner ist als Δd / Δx = 1 / 2 d / x ,
• dass für die Periodendicke d gilt: 1 nm ≤ d ≤ 20 nm,
• dass für die Anzahl N der Perioden gilt 10 < N < 500, vorzugsweise 50 ≤ N ≤ 100,
• und dass für die Energie E der Lichtquanten der Röntgenstrahlung gilt: 0,1 keV < E < 0,1 MeV.

Furthermore, the embodiments of the x-ray analysis device according to the invention with a paraboloid reflector shape have the properties

• that the layers of the reflector are evaporated, sputtered or grown directly on a concavely curved surface of a paraboloidally hollowed-out substrate, the curvature of the concave substrate surface in an xz plane following the formula z ² = 2px with 0.02 mm <p <0, 5 mm, preferably p ≈ 0.1 mm;
• that the concave substrate surface facing the reflector has a maximum permissible shape deviation of Δp = 2px ΔΘ _R , where ΔΘ _{R is} the half width of the Bragg reflection of the reflector, and is in the range 0.01 ° <ΔΘ _R <0.5 °, preferably 0.02 ° <ΔΘ _R <0.20 °,
• that the concave substrate surface facing the reflector has a maximum permissible waviness of Δz / Δx = 1/2 ΔΘ _R ,
• that the concave substrate surface facing the reflector has a maximum permissible roughness of Δz = d / 2π, preferably Δz ≤ 0.3 nm,
• that the X-rays hit the curved surface of the reflector at an angle of incidence of 0 ° ≤ Θ ≤ 5 °,
• that the period thickness d changes along the x direction in such a way that the X-ray radiation of a specific wavelength λ from a point-shaped X-ray source always experiences Bragg reflection regardless of the point of impact (x, z) on the reflector, in that the period thickness d towards the paraboloid opening in x Direction according to d = λ / 2 1 / (1- δ / sin ² Θ) sin Θ and Θ = arc cot 2px p increases, whereby δ is the decrement of the average refractive index of the multilayer Bragg reflector,
• that the deviation Δd / Δx of the period thickness d at each point of the multilayer Bragg reflector along the x direction is smaller than Δd / Δx = 1/2 d / x,
• that applies to the period thickness d: 1 nm ≤ d ≤ 20 nm,
• that 10 <N <500, preferably 50 N N 100 100, applies to the number N of periods,
• and that for the energy E of the light quanta of the X-rays: 0.1 keV <E <0.1 MeV.

The use of amorphous or polycrystalline is also advantageous Substrate material, especially glass, amorphous Si, polycrystalline Ceramic material or plastic. Regarding the number of individual layers per Period, 2, 3 or 4 layers are particularly recommended. The Layer thicknesses of the individual layers differ from material to material preferably by a maximum of 5%.

Conventional (rotationally symmetrical) Goebel mirrors according to the state of the Technology are described for example in DE 198 33 524 A1, whereupon hereby full reference is made.

Claims (14)

Reflector (5) for X-rays (2, 3, 10, 11), which is curved along a first cross-section (13) in a plane (XZ) containing an x direction, the reflector (5) also along a second cross section (14) is curved in a plane (YZ) perpendicular to the x direction,
characterized in that the reflector (5) along the second cross-section (14) also has a curvature that deviates from an arc. Reflector (5) according to claim 1, characterized in that the curvature of the reflector (5) along the second cross-section (14) sets the focusing properties of the reflector (5), in particular in the plane perpendicular to the x direction (YZ). Reflector (5) according to one of the preceding claims, characterized in that the reflector (5) is two-dimensionally focusing or parallelizing. Reflector (5) according to one of the preceding claims, characterized in that the reflector (5) along the first cross section (13) is parabolic, hyperbolic or elliptically curved. Reflector (5) according to one of the preceding claims, characterized in that the reflector (5) has a periodically repeating sequence of layers of materials A, B, ... with different refractive index, the sum d = d _A + d _B + ... the thicknesses d _A , d _B , ... of successive layers of materials A, B, ... changes continuously, in particular monotonically, along the x-direction. Reflector (5) according to claim 5, characterized in that the sum d changes along the second cross section (14), in particular by more than 2%. A reflector (5) according to claim 6, characterized in that the curvature of the reflector (5) along the second cross-section (14) changes the sum d along the second cross-section (14) compared to a comparison reflector with a constant sum d and circular curvature along whose second cross-section is compensated for the focusing and reflectivity properties of the reflector (5). Reflector (5) according to one of the preceding claims, characterized in that the reflector (5) along the second cross-section (14) has an elliptical curvature with different lengths of the semiaxes or a parabolic curvature. Reflector (5) according to one of the preceding claims, characterized in that the reflector (5) has a reflective surface of more than 2 mm, preferably at least 4 mm in width (measured perpendicular to the x-direction). X-ray analyzer with an X-ray source (1), one too analyzing sample (6), an X-ray detector (7), beam-shaping and / or beam-limiting means (4) and a reflector (5) any of the preceding claims. X-ray analyzer according to claim 10, characterized in that X-rays (2, 3; 10, 11) impinges on the reflector (5) at an angle (9) of less than 5 ° to the x direction. X-ray analyzer according to one of claims 10 or 11, characterized in that the curvature of the reflector (5) along the second cross-section (14) is designed such that the reflectivity of the reflector (5) for the wavelength of the generated by the x-ray source (1) Radiation is maximum. X-ray analyzer according to one of claims 10 to 12, characterized in that the reflector (5) incident X-rays (2, 3; 10, 11) on a point-like area (focal spot), in particular on the sample (6) or on the X-ray detector (7) focused. X-ray analysis device according to one of Claims 10 to 12, characterized in that the reflector (5) generates an X-ray beam with a specific beam divergence, in particular a parallel beam, from X-ray radiation (2, 3; 10, 11) incident on it.

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