Patent Description:
An X-ray generator capable of radiating a focused X-ray beam having a small beam size onto a desired position (e.g., a position where a sample is disposed) has been used.

<CIT> discloses a dual mode scattering system or a dual mode diffraction system. As disclosed in Fig. 3A in <CIT>, a radiation source <NUM> is a line source of radiation, and an X-ray beam from the radiation source <NUM> passes through a second opening of an aperture <NUM> and interacts with both a first surface <NUM> and a second surface <NUM> of a KB optical system, thereby forming, for example, a two-dimensional beam <NUM> serving as a point beam. <FIG> in <CIT> discloses a dual mode small-angle X-ray scattering system in a two-dimensional operating mode.

<CIT> discloses an X-ray optical system in which a polycapillary <NUM> is used to obtain a point-like X-ray beam. In the X-ray optical system, a third state in which a focused beam whose cross section is focused into a point shape is obtained is realized.

From <CIT> an X-ray optical system is known that comprises an X-ray source in point or line geometry, a first optical system including two optics for conditioning the X-rays to form two beams and at least a second optical system or element which further conditions at least one of the two beams from the first optical system.

Further from <CIT> an X-ray transmission spectrometer system is known comprising an X-ray source for generating X-rays and an X-ray optical system configured to produce a focused X-ray beam. According to one implementation (see Figs 5A and 5B) the optical system comprises a paraboloidal reflector designed and arranged for generating a collimated X-ray beam and a tube-shaped focusing element with a paraboloidal inner surface for focusing the collimated x-rays.

Conventionally, a line X-ray source has been widely used in an X-ray diffraction measurement in view of the balance between a resolution and a sample size.

The dual mode scattering system or the dual mode diffraction system disclosed in <CIT> and <CIT> includes the line X-ray source (the radiation source <NUM>) widely used because of the reason described above. However, for forming a focused X-ray beam (a two-dimensional beam), the X-ray beam from the radiation source <NUM> is limitedly selected (narrowed) by the second opening, which is, for example, a square hole; therefore, a high-intensity focused X-ray beam is not realized even when the X-ray beam that has passed through the second opening is focused.

In the X-ray optical system disclosed in <CIT>, the polycapillary <NUM> is used to realize a focused X-ray beam; therefore, the divergence angle of the X-ray beam is large, leading to a reduction in resolution in X-ray diffraction measurement.

The invention has been made in view of the problems, and it is an object of the invention to provide an X-ray generator and an X-ray analysis device that are capable of realizing with a simple configuration a focused X-ray beam whose beam size is small and whose divergence angle is small.

The invention provides an X-ray generator and an X-ray analysis device that are capable of realizing with a simple configuration a focused X-ray beam whose beam size is small.

Hereinafter, an embodiment of the invention will be described with reference to the drawings. In the drawings, dimensions, shapes, and the like may be schematically represented, compared to those in practicing aspects of the invention, for more clarity of description. However, they are illustrative only and do not limit the interpretation of the invention. In the specification and the drawings, elements similar to those described in relation to a previous drawing are denoted by the same reference numerals and signs, and a detailed description may be appropriately omitted.

<FIG> is a schematic view showing the configuration of an X-ray analysis device <NUM> according to the embodiment of the invention. Here, the X-ray analysis device <NUM> according to the embodiment is an X-ray diffractometer device (XRD) but is not limited to this. The X-ray analysis device <NUM> may be a small-angle X-ray scattering device (SAXS) or may be other X-ray analysis devices. The X-ray analysis device <NUM> according to the embodiment includes an X-ray source portion <NUM>, a CBO unit <NUM>, a focusing element <NUM>, an aperture <NUM>, a collimator <NUM>, a support stage <NUM> to support a sample <NUM>, a two-dimensional detector <NUM>, a goniometer <NUM>, and a moving mechanism <NUM>. An X-ray generator <NUM> (not shown) according to the embodiment includes the X-ray source portion <NUM>, the CBO unit <NUM>, the focusing element <NUM>, the aperture <NUM>, the collimator <NUM>, and the moving mechanism <NUM>. In the specification, the X-ray generator includes not only the X-ray source portion emitting an X-ray but also an X-ray optical system portion that forms an X-ray beam to be radiated onto a sample. Here, the X-ray optical system portion includes the CBO unit <NUM>, the focusing element <NUM>, the aperture <NUM>, and the collimator <NUM>. However, the collimator <NUM> is not essential but may be used as necessary.

The goniometer <NUM> is a θ-θ goniometer of a horizontally disposed sample type. The goniometer <NUM> can perform 2θ scan while horizontally holding the sample <NUM> supported on the support stage <NUM>. By horizontally placing the sample <NUM>, the influence of bend of the sample <NUM> due to its weight can be minimized, and the risk of falling of the sample <NUM> can be suppressed. The goniometer <NUM> includes two arms extending from the sample <NUM> supported by the support stage <NUM> at the center. A typical direction of an X-ray beam that propagates from the focusing element <NUM> to the sample <NUM> is defined as an x-axis direction, and a plane that is perpendicular to the x-axis direction is defined as a yz plane. The X-ray source portion <NUM>, the CBO unit <NUM>, the focusing element <NUM>, the aperture <NUM>, the collimator <NUM>, and the moving mechanism <NUM> are mounted on one of the arms along the x-axis direction. The two-dimensional detector <NUM> is mounted on the other arm. The two arms rotate by θ in opposite directions with each other with respect to the sample <NUM>, and thus the two-dimensional detector <NUM> can be rotated by 2θ when the sample <NUM> rotates by θ with respect to an X-ray beam that is incident on the sample <NUM>.

The X-ray source portion <NUM> includes a rotor target. By radiating an electron beam whose cross section is linear onto the rotor target, X-rays are generated by a rotor target surface. Through a slit window disposed in parallel with an axis of rotation of the rotor target, an X-ray that transmits through the slit window, in the X-rays generated by the rotor target, is emitted to the outside. The X-ray source portion <NUM> can be deemed to include a line X-ray source 11A. It is sufficient that the X-ray source portion <NUM> includes one that includes (can be deemed to include) a line X-ray source, without limiting to a rotor target, and the X-ray source portion <NUM> may include, for example, a sealed tube.

The CBO (cross beam optics) unit <NUM> includes a slit plate <NUM> (not shown) including two slits 31A and 31B (not shown) on an incident side, and further includes a multilayer film mirror 12A (not shown). One (31A) of the two slits 31A and 31B is for a direct beam, and the other (31B) is for a collimated beam that is monochromatically collimated by the multilayer film mirror 12A. By moving the two slits 31A and 31B in a direction (y-direction) perpendicular to an optical axis (a propagation direction of the X-ray beam: a z-axis) of the X-ray beam, a user selects whether to use the slit 31A for the direct beam or the slit 31B for the collimated beam. In the embodiment, the slit 31B for the collimated beam is selected. Herein, the X-ray generator <NUM> (the X-ray optical system portion) includes the CBO unit <NUM> but is not limited to this. It is sufficient that the X-ray generator <NUM> (the X-ray optical system portion) includes an optical component including the multilayer film mirror 12A.

A cross section of a reflecting surface of the multilayer film mirror 12A has a parabolic shape. The multilayer film mirror 12A is disposed such that the focus of the parabolic shape is located at the line X-ray source 11A. The multilayer film mirror 12A has a multilayer structure in which a characteristic X-ray (herein Cu Kα X-ray) serving as a target is selectively reflected. In X-rays emitted from the line X-ray source 11A, an X-ray beam that reaches the reflecting surface of the multilayer film mirror 12A is reflected at the reflecting surface of the multilayer film mirror 12A and monochromatically collimated.

The focusing element <NUM> includes a side-by-side reflecting mirror 13A (not shown) including two concave mirrors joined together. Herein, for focusing the collimated X-ray beam, each of cross sections of the two concave mirrors has a parabolic shape, and the collimated X-ray beam incident on the side-by-side reflecting mirror 13A is focused on a confocal point of the side-by-side reflecting mirror 13A located on the side opposite to the multilayer film mirror 12A.

The X-ray source portion <NUM>, the CBO unit <NUM>, and the focusing element <NUM> are fixed to one another and integrated. The CBO unit <NUM> is fixed to the X-ray source portion <NUM>, and the focusing element <NUM> is fixed to the CBO unit <NUM>. The integrated these components are mounted on the moving mechanism22. The moving mechanism <NUM> includes, for example, connecting portions 22A to be joined to the X-ray source portion <NUM>, and a step motor controls the movement of the connecting portion 22A on a rail 22B. In the embodiment, the moving mechanism <NUM> includes two connecting portions 22A and two rails 22B respectively moving the two connecting portions 22A. Details will be described later.

The collimator <NUM> absorbs a scattering X-ray beam and transmits a straight traveling X-ray beam. The collimator <NUM> selectively transmits a desired focused X-ray beam of X-ray beams emitted from the focusing element <NUM>. It is sufficient that the collimator <NUM> is disposed as necessary, and the collimator <NUM> may not be necessarily disposed.

The two-dimensional detector <NUM> is a detector capable of two-dimensionally detecting an X-ray generated from the sample <NUM>, but is not limited to this. The two-dimensional detector <NUM> may be a one-dimensional detector or a scintillation detector as necessary. Moreover, an RxRy attachment for sample tilt alignment to be performed before in-plane measurement or reciprocal space map measurement may be mounted on the support stage <NUM> supporting the sample <NUM>.

<FIG> is a schematic views showing the configuration of the X-ray generator <NUM> according to the embodiment. As shown in <FIG>, only main components are shown for clarity of the state of an X-ray beam. <FIG> is a side view of the X-ray generator <NUM>. <FIG> is a plan view of the X-ray generator <NUM>. In <FIG>, the line X-ray source 11A of the X-ray source portion <NUM>, the slit plate <NUM> and the multilayer filmmirror 12A of the CBO unit <NUM>, the side-by-side reflecting mirror 13A of the focusing element <NUM>, and the aperture <NUM> are shown. As shown in <FIG>, the side view of the X-ray generator <NUM> shows an xz plane, and the plan view of the X-ray generator <NUM> shows the xy plane.

<FIG> is a cross-sectional view of the side-by-side reflecting mirror 13A according to the embodiment, showing the yz plane. As shown in <FIG>, the side-by-side reflecting mirror 13A includes two concave reflecting mirrors 40A and 40B. According to the claimed invention, the cross sections of reflecting surfaces of the two concave reflecting mirrors 40A and 40B each have a parabolic shape, and it is further desirable that the two concave reflecting mirrors 40A and 40B are substantially equivalent to each other. In the side-by-side reflecting mirror 13A, the two concave reflecting mirrors 40A and 40B are joined in contact with each other so as to share a join line 40C. The two concave reflecting mirrors 40A and 40B each have the reflecting surface serving as a concave, and the reflecting surface can be closely akin to a plane. The two concave reflecting mirrors 40A and 40B are joined such that the reflecting surfaces of the two concave reflecting mirrors 40A and 40B intersect with each other, and it is desirable that the two concave reflecting mirrors 40A and 40B are joined so as to be substantially at a right angle. Here, the phrase "substantially at a right angle" means that an angle θ formed by the reflecting surface of the concave reflecting mirror 40A and the reflecting surface of the concave reflecting mirror 40B via the join line 40C is <NUM>° or more and <NUM>° or less, and it is further desirable that the angle θ is <NUM>° or more and <NUM>° or less. It is needless to say that the angle θ is still desirably <NUM>°.

In a cross section (a cross section perpendicular to the x-axis direction) of the side-by-side reflecting mirror 13A, one (the concave reflecting mirror 40A) is disposed on the counterclockwise side and the other (the concave reflecting mirror 40B) is disposed on the clockwise side, with respect to the z-axis direction. It is desirable that the concave reflecting mirror 40A and the concave reflecting mirror 40B are disposed such that a cross section of the concave reflecting mirror 40A and a cross section of the concave reflecting mirror 40B are nearly plane symmetrical with a plane including the z-axis and the join line 40C being as a symmetry plane. Ideally, it is desirable that the cross sections are plane symmetrical, but it is sufficient that the cross sections are substantially plane symmetrical. It is desirable that an angle ϕ formed by the reflecting surface of the concave reflecting mirror 40A and the y-axis direction is substantially <NUM>°. Here, the phrase "substantially <NUM>°" means that the angle ϕ is <NUM>° or more and <NUM>° or less, and it is further desirable that the angle ϕ is <NUM>° or more and <NUM>° or less. It is needless to say that the angle is still desirably <NUM>°.

It is desirable that both the focus of the parabolic shape that is the cross section of the reflecting surface of the concave reflecting mirror 40A and the focus of the parabolic shape that is the cross section of the reflecting surface of the concave reflecting mirror 40B are included in the sample <NUM>. It is further desirable that these two focuses are as close as possible to each other, and ideally, it is desirable that these two focuses coincide with each other. However, it is sufficient that these two focuses are close to each other to such an extent as to substantially coincide with each other. The focus of the parabolic shape that is the cross section of the reflecting surface of the concave reflecting mirror 40A and the focus of the parabolic shape that is the cross section of the reflecting surface of the concave reflecting mirror 40B substantially coincide with each other, and the side-by-side reflecting mirror 13A according to the embodiment is a confocal reflecting mirror.

In collimated X-ray beams that reach the side-by-side reflecting mirror 13A, an X-ray beam that passes through an area A shown in <FIG> is focused. The area A has substantially a square shape, and the length (diagonal) in the y-axis direction is approximately <NUM>. Moreover, for comparison, a cross-sectional shape of the multilayer film mirror 12A is represented by an imaginary line, and the length of the multilayer film mirror 12A in the y-axis direction is approximately <NUM>.

As shown in <FIG>, the side-by-side reflecting mirror 13A is disposed such that an extended line of the join line 40C of the side-by-side reflecting mirror 13Apasses through the center lines of the multilayer film mirror 12A and the line X-ray source 11A as viewed in a plan view. Ideally, it is desirable that the extended line of the join line 40C of the side-by-side reflecting mirror 13A coincides with the center line of the multilayer film mirror 12A and the center line of the line X-ray source 11A as viewed in a plan view; however, the invention is not limited to this, and it is sufficient that the extended line of the join line 40C substantially coincides with the center lines. It is sufficient that the extended line of the join line 40C of the side-by-side reflecting mirror 13A at least passes through the multilayer film mirror 12A and the line X-ray source 11A as viewed in a plan view.

In X-rays emitted by the line X-ray source 11A, an X-ray beam that reaches the reflecting surface of the multilayer film mirror 12A is reflected by the reflecting surface and collimated. The collimated X-ray beam is focused by the side-by-side reflecting mirror 13A. By disposing the sample <NUM> at the focus of the X-ray beam, a small X-ray beam can be radiated onto the sample <NUM>, which can realize measurement for a small sample or mapping of small portion of a sample.

The X-ray generator according to the embodiment can realize with a simple configuration a focused X-ray beam having a high intensity and a small beam size (focus size) by use of the line X-ray source, the multilayer film mirror, and the side-by-side reflecting mirror. Here, the small beam size is <NUM> or less. With use of the line X-ray source, a point-focused beam can be easily obtained by disposing the side-by-side reflecting mirror 13A in measurement using a high integrated intensity.

As shown in <FIG>, a propagation direction of an X-ray is the x-axis direction as viewed in a plan view (in an xy plane) , and it is easy to adjust an optical axis. However, an X-ray beam is reflected at the multilayer film mirror 12A and the side-by-side reflecting mirror 13A, and a shift in the focal position of the focused X-ray beam occurs with respect to the z-axis direction. The present inventors have studied that, for example, a shift of approximately <NUM> occurs in the embodiment. In the X-ray generator <NUM> according to the embodiment, the X-ray source portion <NUM>, the CBO unit <NUM>, and the focusing element <NUM> are fixed to one another and integrated as described above. That is, mutual relative positions of the line X-ray source 11A, the multilayer film mirror 12A, and the side-by-side reflecting mirror 13A are fixed. It is desirable that the mutual relative positions of the X-ray source portion <NUM>, the CBO unit <NUM>, and the focusing element <NUM> are brought into a still preferred state by carrying out an optical axis adjustment and thereafter that the X-ray source portion <NUM>, the CBO unit <NUM>, and the focusing element <NUM> are fixed to one another. The moving mechanism <NUM> can translate the line X-ray source 11A, the multilayer film mirror 12A, and the side-by-side reflecting mirror 13A as one integrated body along an extending direction of the rail 22B by moving with the step motor the connecting portion 22A on the rail 22B. Here, the extending direction of the rail 22B is along the z-axis direction. It is desirable that the extending direction (a translation direction of the moving mechanism <NUM>) of the rail 22B coincides with the z-axis direction; however, the extending direction does not necessarily need to coincide therewith, and it is sufficient that the extending direction is a direction that intersects with the propagation direction of the X-ray beam. It is ideal that an angle formed by the extending direction and the propagation direction of the X-ray beam is <NUM>°; however, it is sufficient that the angle is <NUM>° or more. It is further desirable that the angle is <NUM>° or more.

<FIG> show a beam size of a focused X-ray of the X-ray generator <NUM> according to the embodiment. <FIG> shows a result of z-axis-direction scanning of a slit disposed at a position where a sample is disposed or in the vicinity of the position. <FIG> shows a result of y-axis-direction scanning of the slit disposed at the position where the sample is disposed or in the vicinity of the position. <FIG> shows the position where the slit is disposed in the x-axis direction. The scanning is performed in a state where the angle θ of the goniometer <NUM> is <NUM>°, that is, in a state where the X-ray source portion <NUM>, the support stage <NUM>, and the two-dimensional detector <NUM> are disposed substantially in a straight line, and the two-dimensional detector <NUM> detects an X-ray intensity of the focused X-ray.

<FIG> shows by four curves the intensity of the focused X-ray scanning in the z-axis direction, when the position in the x-axis direction is at -<NUM>, -<NUM>, <NUM>, and +<NUM> as shown in <FIG>, at the origin position in the y-axis direction. <FIG> shows by four curves the intensity of the focused X-ray scanning in the y-axis direction, when the position in the x-axis direction is at -<NUM>, -<NUM>, <NUM>, and +<NUM> as shown in <FIG>, at the origin position in the z-axis direction.

As shown in <FIG>, in the case of z-axis-direction scanning of the slit, an X-ray beam whose peak intensity is low and whose peak width is wide when the position in the x-axis direction is at +<NUM> and -<NUM> is high in peak intensity and is narrowed in peak width when the position in the x-axis direction is the position (<NUM>) where the sample is disposed. Further, at the position of -<NUM>, the peak intensity is further high and the peak width is further narrowed, so that an X-ray beam whose focus size is small can be realized and that an X-ray optical axis adjustment can be realized.

As shown in <FIG>, in the case of y-axis-direction scanning of the slit, an X-ray beam whose peak intensity is low and whose peak width is wide when the position in the x-axis direction is at +<NUM> and -<NUM> is high in peak intensity and is narrowed in peak width when the position in the x-axis direction is the position (<NUM>) where the sample is disposed. Further, at the position of -<NUM>, the peak intensity is further high and the peak width is further narrowed, so that an X-ray beam whose focus size is small can be realized and that an X-ray optical axis adjustment can be realized.

<FIG> shows an experimental result of the X-ray analysis device <NUM> according to the embodiment. A two-dimensional scattering image obtained by grazing-incidence small-angle X-ray scattering (GI-SAXS) measurement, in which an X-ray is incident at a grazing angle on the surface of the sample <NUM> and the X-ray reflected and scattered is measured by the two-dimensional detector, is shown. A focused X-ray beam whose focus size is small is realized by the X-ray generator <NUM>, and thus spot-like reflection is confirmed in the two-dimensional scattering image shown in <FIG>. Moreover, since the spread of lattice points in an arc direction is confirmed, it is considered that a random component is contained.

Claim 1:
An X-ray generator (<NUM>) comprising:
a line X-ray source (11A);
a multilayer film mirror (12A) for reflecting the X-ray; and
a side-by-side reflecting mirror (13A) including two concave mirrors (40A, 40B) joined together so as to share a join line (40C), wherein:
a cross section of a reflecting surface of the multilayer film mirror (12A) has a parabolic shape and a focus of the parabolic shape is located at the line X-ray source (11A); and
cross sections of reflecting surfaces of the two concave mirrors (40A, 40B) of the side-by-side reflecting mirror (13A) each have a parabolic shape and each of focuses of the parabolic shapes is located on a side opposite to the multilayer film mirror (12A), and wherein both focuses substantially coincide with each other.