JPH11211895A - X-ray optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray optical device having a large effective solid angle and excellent efficiency. SOLUTION: An X-ray zone plate 3 and X-ray Schwarzschild mirrors 1, 2 are concurrently used, and the zone plate 3 is located on the optical axis of the mirrors 1, 2. The Schwarzschild mirrors 1, 2 have holes at the center, the X-ray beam at the portions is not utilized, however the unutilized X-ray beam can be utilized by arranging the X-ray zone plate 3 there, and efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an X-ray optical apparatus used for X-ray focusing or X-ray imaging.

[0002]

2. Description of the Related Art A multilayer X-ray reflector in which thin films of heavy elements and light elements are alternately layered on a substrate has been put to practical use. This means that heavy elements such as W, Mo, Cr, Au, etc., and light elements such as B, C, Al
For example, a pair of a heavy element film and a light element film (referred to as a layer pair) having a layer thickness of 1 nm or more is manufactured. X-ray reflection is due to mutual interference of scattered X-rays on the heavy element film, and is Bragg reflection. Therefore, when the thickness of a pair of light and heavy element films is set to 5.0 nm, the X-ray wavelength for perpendicular incident reflection is 10 nm. With a number of layers of about 30 and a reflectivity of about 40%, it can be obtained. The mirror diameter is 15c
Made up to m-th place. X-ray zone plate is 5m in diameter
It is made up to m-th.

The Schwarzschild type mirror has a large concave primary mirror and a small convex secondary mirror opposed to each other like a Cassegrain telescope, and a hole through which the X-ray flux reflected by the convex secondary mirror passes is formed at the center of the primary mirror. ing. An X-ray condensing device using an X-ray reflecting mirror includes a device using a Walter-type mirror in addition to the above. This is a combination of a hyperboloid and an elliptical mirror, in which one of the focal points is an X-ray source and the other is a focal point.

Each type of X-ray optical device described above has the following advantages and disadvantages. When a Schwarzschild type mirror is used, the solid angle of the primary mirror with respect to the X-ray source can be increased, but since a hole is formed in the center of the primary mirror, the central part of the X-ray flux cannot be used. In the case of using a Walter-type mirror, the X-ray reflection angle is higher than that of the Schwarzschild type because the X-ray incidence angle to the mirror is obliquely incident and reflected, but the solid angle of the mirror with respect to the X-ray source is smaller than that of the Schwarzschild type. Overall, lower efficiency than Schwarzschild type. A device using a zone plate has a smaller zone interval and cannot produce a large-diameter object than a device using a visible light, so that a solid angle with respect to an X-ray source is small and an X-ray utilization factor is low.

[0005]

An X-ray optical device using a Schwarzschild type mirror is intended to improve the point that the center of the X-ray flux cannot be used, and to obtain an X-ray optical device with high efficiency as a whole. It is.

[0006]

An X-ray zone plate is provided in a central portion of a convex sub-mirror of a Schwarzschild type mirror for X-ray, which is opposed to a concave main mirror. The X-ray source position and the converging point are set to coincide with the X-ray source position and the converging point of the Schwarzschild mirror.

[0007]

FIG. 1 shows one embodiment of the present invention. In the figure, reference numeral 1 denotes a primary mirror of a Schwarzschild X-ray mirror, and a hole 1H through which an X-ray flux passes is formed at the center. Reference numeral 2 denotes a secondary mirror of the Schwarzschild type X-ray mirror, which has a hole 2H in the center thereof so that an X-ray flux passes therethrough, and an X-ray Fresnel zone plate 3 is mounted thereon. S is an X-ray source and F is X
This is the focal point of the line. These points S and F are the source of the combination of the Schwarzschild mirrors 1 and 2 and their image points, as well as the source of the zone plate 3 and their image points. When the Schwarzschild mirrors 1 and 2 are quartz substrates, the reflection film is made of Co as a heavy element and B is used as a light element, and the thickness d of one pair of X-ray reflection films is set to 5.0 nm, the vertical incidence is reduced. High reflectivity is obtained for soft X-rays having a wavelength of 10 nm in a range close to reflection. In the figure, S is an X-ray source, F is an X-ray focusing point, and the zone plate 3 is arranged between the source S and the focusing point F. Although this arrangement is an enlarged projection optical system, a reduced projection optical system can also be configured by disposing the point F in the figure as an X-ray source and the point S as a converging point.

In the example shown in FIG. 1, the zone plate 3 is brought into close contact with the back surface (the X-ray source side) of the sub-mirror 2, but the positional relationship between the primary mirror 1, the sub-mirror 2, and the zone plate 3 is such an arrangement. Not limited. The zone plate and the secondary mirror may be separated. Since the positional relationship between the source and the focal point of the zone plate is the same as that of an ordinary lens, the intervals between the zone plate 3 and the X-ray source S and the focal point F can be set arbitrarily. Since the angle of incidence and reflection of X-rays is smaller in the secondary mirror than in the primary mirror, it is desirable that the layer-to-thickness of the reflective film be smaller than that of the primary mirror.
No. In the example of FIG. 1, the distance from the X-ray source to the center of the primary mirror 1 is 60c.
m, the position of the X-ray source image S 'by the primary mirror 1 is 20
cm, the primary mirror diameter is 5 cm, the secondary mirror diameter is 1.5 cm, and the radius of the zone plate 3 is 2.0 mm. In this configuration, the effective range of the primary mirror 1 is between a radius of 1.5 cm and 2.25 cm, and accordingly, the secondary mirror 2 has an effective inner diameter of 1 cm and an effective outer diameter of 0.5 c.
m.

[0009]

According to the X-ray optical apparatus of the present invention, the central portion of the X-ray flux which has not been used in the Schwarzschild mirror is used by the combined use of the X-ray zone plate. Considering mainly the zone plate, the zone plate could only use X-rays within a narrow solid angle in the X-ray flux, but the solid angle of the X-ray flux that can be used with the Schwarzschild type mirror was expanded. In any case, an X-ray optical device brighter than the conventional one can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 Primary mirror of Schwarzschild mirror 2 Secondary mirror 3 Zone plate S X-ray source F X-ray focusing point

Claims (1)

[Claims] The X-ray source and the X-ray focal point of the mirror are aligned on the optical axis of a Schwarzschild type X-ray mirror composed of a primary mirror and a secondary mirror having a multilayer film for X-ray reflection formed on the surface, and an X-ray Fresnel An X-ray optical apparatus comprising a zone plate and a hole through which an X-ray flux passes in the center of the secondary mirror.