JPH08201600A - X-ray microscope - Google Patents

Abstract

PURPOSE: To shield stray light generated from a zone plate in a microscope using a zone plate as an optical element for capacitor. CONSTITUTION: X-ray generated from an X-ray source 1 is focused with a zone plate 2. By arranging behind the zone plate 2 a diaphragm plate 3 which has a pin hole 3a in the center and is formed free of moving in the directions of the optical axis and a plane perpendicular to this and taking out necessary X-ray, a specimen 4 is irradiated with the X-ray having passed through the pin hole 3a. The X-ray image of the specimen 4 is focused on a screen 6 with a focusing optical system 5. In this X-ray microscope, a light shield plate 7 having an opening 7a in the center is arranged between the zone plate 2 and the screen 6 so that the X-ray passing outside of the diaphragm plate 3 and reaching the screen 6 is shielded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray microscope using a zone plate as an optical element for a condenser, and more particularly to blocking stray light generated from the zone plate.

[0002]

2. Description of the Related Art X-ray microscopes have been attracting attention because they can observe biological samples untreated and with high resolution. In an X-ray microscope using a zone plate as a condenser, a pinhole is installed at the focal position of the zone plate in order to disperse and extract X-rays of a desired wavelength. Here, the member having the pinholes is called a diaphragm plate. Since an X-ray microscope usually uses soft X-rays, the light source, optical system, and detector are installed in a vacuum chamber. Further, the diaphragm plate is held by a moving mechanism of a total of three axes in the optical axis direction and two directions perpendicular to and orthogonal to the optical axis in order to facilitate the adjustment of the optical axis.

[0003]

When a non-monochromatic light source is used, the diffracted light of the X-ray different from the desired wavelength on the condenser zone plate forms a large spread on the diaphragm plate. Further, even at a desired wavelength, X-rays other than the desired diffraction order form a spread on the diaphragm plate. On the other hand, since the diaphragm plate is held by the moving mechanism and installed in the vacuum chamber, it necessarily has a gap with the inner wall of the vacuum chamber, and as a result, the outside of the diaphragm plate is completely shielded from light. However, there was a problem that stray light was mixed in the image. Therefore, an object of the present invention is to block stray light generated from a zone plate in an X-ray microscope using the zone plate as an optical element for condenser.

[0004]

The present invention has been made to achieve the above object, that is, X-rays generated from an X-ray source are condensed by a zone plate and have a pinhole at the center. A diaphragm plate movably formed in the optical axis direction and a plane direction orthogonal to the optical axis direction is arranged behind the zone plate to take out necessary X-rays, and a sample is arranged behind the diaphragm plate to obtain the sample. In an X-ray microscope that irradiates X-rays that have passed through a pinhole and forms an X-ray image of a sample on an image plane by an imaging optical system, a light shield that has an opening at the center between the zone plate and the image plane The X-ray microscope is characterized in that a plate is arranged to block X-rays passing through the outside of the diaphragm plate from reaching the image plane.

[0005]

In the present invention, since the light shielding plate is installed, it is possible to block the light that advances to the image plane without being blocked by the diaphragm plate.

[0006]

The present invention will be described with reference to the drawings. FIG. 1 shows an X-ray microscope according to an embodiment of the present invention. In a vacuum chamber 8, an X-ray source 1, a condenser zone plate 2, a light shielding plate 7, a diaphragm plate 3, a sample 4, an objective optical element 5 and The detectors 6 are arranged coaxially in that order. A pinhole 3a is opened in the center of the diaphragm plate 3, and the diaphragm plate 3 is attached to a stage (not shown) that is movable in the optical axis direction z and two axes x and y perpendicular to and perpendicular to the optical axis direction z. . An opening 7a having a diameter smaller than the outer diameter of the diaphragm plate 3 is provided at the center of the light shield plate 7, and the outer peripheral surface of the light shield plate 7 is fixed to the inner surface of the vacuum chamber 8. The present embodiment is formed as described above, and the X-ray generated from the X-ray source 1 is condensed by the condenser zone plate 2 and the diaphragm plate 3 blocks unnecessary wavelengths and unnecessary diffraction orders. Then, only the X-ray of a desired diffraction order of a desired wavelength passes through the pinhole 3a and is irradiated on the sample 4. The X-ray image of the sample 4 is formed on the detector 6 by the objective optical element 5.

Therefore, among the X-rays generated from the X-ray source 1 and diffracted by the condenser zone plate 2, X-rays having an unnecessary wavelength and an unnecessary diffraction order form a spread on the diaphragm plate 3. , X-rays trying to pass through the outside of the diaphragm plate 3
It is blocked by the light shield 7 and does not reach the detector 6. Therefore, stray light generated from the zone plate 2 is blocked and a clear image can be obtained. In order to obtain the above effect, it is preferable that the light shield plate 7 is arranged sufficiently close to the diaphragm plate 3 so as not to hinder the movement of the diaphragm plate 3. In addition, although the case where the light shielding plate 7 is arranged between the zone plate 2 and the diaphragm plate 3 is shown in this embodiment, the light shielding plate 7 is provided behind the sample 4.
Can also be arranged to block stray light generated from the zone plate 2.

[0008]

As described above, according to the present invention, it is possible to completely block the light that reaches the image plane from other than the pinhole, so that it is possible to block the stray light due to the diffraction at the zone plate. The X-ray microscope can obtain clear images because it can also block other stray light.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an optical arrangement according to an embodiment of the present invention.
1 ... X-ray source 2 ... Condenser zone plate 3 ... Aperture plate 3a ... Pinhole 4
… Sample 5… Objective optical element 6… Detector 7
... Light-shielding plate 7a ... Opening 8 ... Vacuum chamber

Claims (2)

[Claims] 1. A zone plate which collects X-rays generated from an X-ray source by a zone plate and has a pinhole at the center thereof and is movable in an optical axis direction and a plane direction orthogonal to the zone. The necessary X-ray is taken out by arranging it behind the plate, the sample is arranged behind the diaphragm plate, the sample is irradiated with the X-ray that has passed through the pinhole, and an imaging optical system is used to In an X-ray microscope that forms an X-ray image on an image plane, a light-shielding plate having an opening at the center is arranged between the zone plate and the image plane, and X-rays passing outside the diaphragm plate are X, characterized in that it is blocked from reaching the image plane
Line microscope. 2. The X-ray microscope according to claim 1, wherein the light shielding plate is arranged between the zone plate and the diaphragm plate.