JPH06300897A - X-ray optical device - Google Patents

Abstract

PURPOSE:To enable easily varying an X-ray converged spot diameter using a plurality of mirror for X-rays which has a rotational paraboloid reflection surface and inserting space filters for X-rays between them. CONSTITUTION:X-rays 2 from an X-ray generation region 1 is reflected with a first mirror 3 for X-rays which has a rotational paraboloid shape on the X-ray reflection surface. The reflected X-rays after leaving the mirror 3 become a parallel X-ray flux. Here, a beam stop 7 is used to cut the X-rays not going into the mirror 3. The parallel X-ray flux goes in a reflection type X-ray space filter 4. For the filter 4, a spectrocrystal and the like for example, X-ray multilayer film for making X-ray monocolor, is used. The monocolor parallel X-ray flux becomes a condensed X-ray flux with a second mirror 5 for X-rays. A beam stop 8 shields the X-ray scattered by the filter 4. The mirror 5 has a rotational paraboloid surface on the reflection surface. The condensed X-ray flux becomes a small X-ray spot 6 on the focus point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray optical system used in an X-ray irradiator such as an X-ray analyzer for focusing X-rays generated from the X-ray device.

[0002]

2. Description of the Related Art As a method of condensing X-rays generated from an X-ray device, for example, an X-ray having a spheroidal X-ray reflecting surface is used.
There is a method using a line mirror. The X-ray mirror uses one of the focal points of the ellipsoid of revolution as an X-ray generating portion, and focuses the X-ray generated from the X-ray generating portion on the other focal point. At this time, the X-ray focused spot diameter is determined by the size of the X-ray generation source of the X-ray generator and the reduction ratio of the X-ray mirror. If the size of the X-ray generation source is fixed, the X-ray focused spot diameter determined by the reduction ratio of the X-ray mirror can be obtained.

[0003]

However, the X-ray generated from the X-ray generator is a divergent X-ray flux when entering the X-ray mirror, and a focused X-ray flux when it is emitted from the X-ray mirror. The performance of the X-ray spatial filter such as a dispersive crystal cannot be used sufficiently. This is because the high-performance X-ray spatial filters are currently for parallel X-ray flux. For example, a multilayer film for X-ray spectroscopy is used in which two kinds of substances, which are a heavy element and a light element with respect to X-rays, are alternately stacked. The steeper the interface of the X-ray multilayer film, the better the performance, and therefore the disorder of the interface becomes important. Here, it is known that the turbulence of the interface is greatly affected by the surface roughness of the substrate, and a substrate defined by a quadric surface has a surface roughness larger than that of a flat substrate due to polishing. It gets bigger.

Therefore, as a multilayer film having a function for a dispersive crystal, a flat substrate is used, and a uniform film is attached to the substrate surface. Therefore, with respect to the divergent X-ray flux generated by the X-ray mirror, an angle of deviation from parallel rays comes out, and the spectral condition of the multilayer film cannot be sufficiently satisfied. When a dispersive crystal or the like is used, it is more sensitive to the deviation of the incident angle, so that the angle of the dispersed light is more limited.

The X-ray mirror requires a long focal length for X-rays having high energy,
When assembling a linear optical system, a long optical distance is required, which greatly affects the size of the device itself. Furthermore, when the size of the X-ray generation source is fixed, it is necessary to replace the X-ray mirror when changing the size of the X-ray focused spot, and the X-ray mirror must be changed accordingly. It takes time and effort to adjust the line mirror.

[0006]

The present invention has been made in view of the above points, and uses two or more X-ray mirrors each having a paraboloid of revolution as an X-ray reflecting surface. One is the focus X
According to the X-ray generation region of the line generator, another X-ray mirror was combined on the X-ray optical axis. A space into which a spatial filter for X-rays can be inserted was provided in the space between them. And at least one X-ray mirror can be easily replaced.

[0007]

According to the above construction, the divergent X-rays generated from the X-ray generator are reflected by the X-ray mirror as a parallel X-ray flux, and the parallel X-ray flux is again converted into a focused X-ray flux by the X-ray mirror. , Focus X-rays on the focus of the paraboloid. A parallel X-ray flux exists between the X-ray mirrors, and a high-performance spatial filter for X-rays can be inserted. Further, the focal length can be freely changed by changing the space where the parallel X-ray flux exists. Further, the diameter of the focused X-ray can be freely changed by exchanging the X-ray mirror whose focusing angle is changed to one side.

[0008]

The present invention will be described in detail below with reference to FIG. 1 schematically showing an embodiment. X by X-ray generator
X-rays 2 are generated from the line generation area 1. X-ray generation area 1
Is due to electron beam excitation, laser excitation,
Radiation light and secondary light sources thereof. The generated X-rays are reflected by the first X-ray mirror 3. The first X-ray mirror 3 has a shape of a paraboloid of revolution on the X-ray reflecting surface. The reflected X-rays are emitted from the first X-ray mirror 3 and then parallel X
It becomes a bundle of rays. The beam stop 7 is used to cut off X-rays that do not enter the X-ray mirror. The parallel X-ray flux enters the reflective X-ray spatial filter 4. The reflective X-ray filter 4 is, for example, a dispersive crystal for monochromatic X-rays. For example, an X-ray multilayer film is used. The X-ray multilayer film is provided on a flat silicon wafer, and efficiently makes a parallel X-ray flux into a single color. The monochromatic parallel X-ray flux is converted into a focused X-ray flux by the second X-ray mirror 5. The beam stop 8 shields the X-rays scattered by the reflective X-ray spatial filter 4.

Here, the second X-ray mirror 5 also has an X-ray reflecting surface which is a paraboloid of revolution, and has a function of focusing a parallel X-ray flux. The focused X-ray flux can obtain a minute X-ray spot 6 on the focal point of the X-ray mirror. When the transmission type X-ray spatial filter is used instead of the reflection type X-ray spatial filter 4, the X-ray optical system is as shown in FIG. Transmission type X as a spatial filter for transmission type X-rays
There are a line multilayer film and a collimator for limiting the ring opening. The first X-ray mirror 3 and the second X-ray mirror 5 are not limited to those having a single shape of a paraboloid of revolution, but for X-rays having a combination of a paraboloid of revolution and a hyperboloid of revolution. Mirrors can be used as well.

The X-ray focused spot diameter 6 is determined by the size of the X-ray generation area and the reduction ratio determined by the X-ray optical system. In this optical system, the reduction ratio M is the first X of the incident X-ray.
Oblique incidence angle θ1 on the X-ray mirror 3 and the second X-ray mirror 5
It is determined by the ratio of the oblique incident angle θ2 of X-rays to. Therefore, M = tan θ1 / tan θ2 holds.

For example, when the X-rays generated in the X-ray generation region 1 generate X-rays of about 10 KeV or less, the first X-rays are generated.
The line mirror 3 has an oblique incident angle of 5 mrad, F = 350 mm,
When the inner radius is 3.5 mm and the inner surface is coated with platinum, the X-ray energy of 10 KeV or less is 80
It was reflected at a reflectance of not less than%, and converted into a parallel X-ray flux. When a multi-layer film using Mo and Si is used for the spatial filter 4 for X-rays, the period of which is changed from 350 nm to 13000 nm, and is used, the angle of θ3 is 10 K at a fixed angle of about 1 °.
X-rays from eV to 300 eV could be monochromatic. If the angle of θ3 is made variable, a single multi-layered film can be used to obtain a single color. For example, if a multilayer film with a period of 50Å is used, θ3 is set to 0.
Change from 7 ° to 30 °, 10 KeV to 300
X-rays up to eV could be monochromatic. The monochromatic parallel X-ray flux is condensed by the second X-ray mirror 5. As the second X-ray mirror 5, for example, if the same mirror as the first X-ray mirror 3 is used, X-ray energy up to 10 KeV is condensed with the size of the X-ray generation region. When collecting X-ray energy up to 1.5 KeV, θ2 should be 17 m.
rad, F = 100 mm, inner radius 3.5 mm, and the X-ray reflection surface was used as a substrate such as Pyrex glass that absorbs a small amount of X-rays. At this time, the X-ray focused spot is reduced to 60% of the X-ray generation area.

When focusing X-rays up to 300 eV, in the second X-ray mirror 5, θ2 is set to 40 mra.
d, F = 41 mm, inner radius 3.5 mm, and the X-ray reflection surface was coated with Ni. At this time, the X-ray focused spot was reduced to about 12% of the X-ray generation area. For the second X-ray mirror 5, for example, the above series of X-ray mirrors and the like can be used, and these can be easily replaced in a vacuum.

In order to effectively use the parallel X-ray flux with one X-ray mirror, in the above example, the inner radius is set to 3.5 mm, the second X-ray mirror 5 is completely exchanged, and the optical axis is changed. I made a match. The focal lengths at this time are all 700 m
It matches m. However, since it is a parallel X-ray flux, it is possible to form a large number of X-ray focused spots by arranging a large number of X-ray mirrors each having a small inner diameter at the same time. Also, the same effect can be obtained by fixing the second X-ray mirror 5 and replacing the first X-ray mirror 3. Further, in the first X-ray mirror 3 and the second X-ray mirror 5, the X-ray reflection surface is coated with a single layer film to utilize the property of total reflection of X-rays. It is possible to construct an X-ray optical system similar to that of the above example by coating a multilayer film on and using it.

[0014]

According to the present invention, the X-ray focusing spot can be easily changed without changing the size of the X-ray generation source. Moreover, since the focal length can be set arbitrarily, it is not necessary to change the optical distance in accordance with the change in spot diameter. In addition, when X-ray spectroscopy is performed, X due to diffraction efficiency
The loss of line strength can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment according to the present invention.

FIG. 2 is a schematic view of another embodiment according to the present invention.

[Explanation of symbols]

 1 X-ray generation area 2 X-ray optical axis 3 First X-ray mirror 4 X-ray spatial filter 5 Second X-ray mirror 6 X-ray focused spot 7 Beam stop 8 Beam stop

Claims (2)

[Claims] 1. An X-ray generation area, a first X-ray mirror having a paraboloid of revolution for making X-rays from the X-ray generation area substantially parallel X-rays, and the substantially parallel X-rays. An X-ray optical device having a second X-ray mirror having a paraboloid of revolution for forming a focused X-ray beam. 2. The first X-ray mirror and the second X-ray
An X-ray optical device in which a reflective or transmissive X-ray spatial filter is inserted between the X-ray mirror and the X-ray mirror.