JPH06100677B2 - X-ray diffractometer - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to an X-ray diffractometer without mechanical moving parts.

[Prior art]

In the conventional X-ray diffractometer, the X-ray source is fixed at one place, the sample and the X-ray detector are arranged, and two X-ray detectors are provided for the rotation angle of the sample.
The main part is a goniometer, which is a mechanical mechanism that rotates a double angle. In a conventional X-ray diffractometer, the goniometer is a
Since it is necessary to precisely define the positional relationship with the line detector and to accurately detect its angular position, this is a mechanism that requires high structural accuracy. For this reason, it is difficult to drive at high speed, and there is a problem with the stability of the device during long-term use due to wear of the sliding parts.Because of mechanical backlash, the movement direction during measurement must always be kept constant. There is a mechanical problem that it cannot be performed (it cannot be said that reciprocating motion is performed during measurement and measurement is made in both forward and backward strokes). Also, since there is only one X-ray source, the target will be thermally destroyed when trying to obtain strong X-rays.
It is necessary to use a radiation source.

[Problems to be Solved by the Invention]

As described above, the conventional X-ray diffractometer using the goniometer has problems such as difficulty in high-speed operation, poor long-term stability, and limited movement for measurement due to mechanical restrictions. However, there is a problem in that it is difficult to obtain a strong X-ray because it is a single fixation. The present invention aims to solve the above-mentioned problems and to reduce the weight of the entire apparatus by eliminating mechanical movement parts or a part thereof from the X-ray diffraction apparatus.

[Means for Solving the Problems]

A partially arcuate target is arranged along the circumference with the optical axis of the electron gun as an axis, and the electron beam is bent between the electron gun and the target so as to be incident on the target, and Electron beam deflecting means for deflecting the incident position of the electron beam on the target so as to move along the circumference around the optical axis of the electron gun is arranged so as to face the arc target and share the arc center. A partially arcuate position-sensitive X-ray detector was arranged so that the sample was positioned on the center of the common arc of the target and the X-ray detector.

[Action]

An X-ray source is composed of an electron gun and an arc-shaped target. The electron beam deflecting means moves the electron beam incident position on the target on an arc about the optical axis of the electron gun. This action has the same result as moving one X-ray source around the circumference. A position-sensitive X-ray detector is used as the X-ray detector. This X-ray detector has an arc shape parallel to the target, and the sample is placed at the center of the arc of the target and the X-ray detector. The X-ray incident angle on the sample changes due to the movement of the electron beam incident position of
This corresponds to the rotation of the sample on the goniometer.
The X-rays diffracted and reflected from this sample are incident on and detected by the arc-shaped X-ray detector, so that it is possible to detect the diffracted X-rays without moving the X-ray detector. Since it is a sensitive type, it is possible to detect the X-ray diffraction angle, and it is possible to measure X-ray diffraction without having any mechanical moving parts as a whole. The target is fixed, but the electron beam incident position changes, so the time average of the electron flow load at one point on the target is significantly smaller than that of the conventional fixed target type X-ray source, and strong X-rays are obtained. It becomes very easy.

【Example】

1 and 2 show an embodiment of the present invention. G is an X-ray source and 1 is its vacuum outer casing. The outer casing 1 has a conical shape in which a tubular portion extends from the apex, and the conical portion consists of only a part of the entire circumference as shown in FIG. 2, and the electron gun 2 and the converging lens 3 are provided in the tubular portion. The targets 4 are housed coaxially, and the targets 4 are circumferentially arranged around the bottom surface of the conical portion. The electron beam X is emitted outside the end of the outer casing 1 near the conical portion of the tubular portion,
A deflection coil 5 for deflecting in the Y direction is provided. By this deflection coil, the electron beam is bent toward the target 4 as shown in the figure, and a sine wave deflection signal with a 90 ° phase shift is applied to each of the X and Y deflection coil portions of the deflection coil so that the electron beam is emitted by the electron gun. It is possible to rotate in a conical surface having the optical axis of 2 as an axis. The conical bottom surface of the outer casing 1 is recessed in steps, and an X-ray transmission window 6 is provided around the outer periphery of the recess. The target 4 is an integral part of a ring shape,
A passage 41 through which cooling water flows is provided therein. An X-ray incidence list 7 is arranged inside the stepped recess of the outer casing 1 along the circumference. As shown in FIG. 3, this slit is composed of blades 71 radially arranged along the entire circumference and two or more conical strip-shaped plates 72 holding the blades.
With this slit, of the X-rays emitted from the electron beam irradiation area of the target 4, only the X-ray beam orthogonal to the optical axis extension line of the electron gun 2 is extracted. A sample S is placed with its center located at a point P intersecting the X-ray beam on the extension line of the electron gun 2. Reference numeral 8 denotes a semi-circular X-ray detector, which has a shape forming a part of the circumference as shown in FIG. 2, and is placed in the conical notch of the outer casing 1 so as to face the target 4. . This X-ray detector is a position-sensitive X-ray detector. When the electron beam is deflected by the configuration described above, the incident angle α of the X-ray on the sample S changes in FIG. Since the X-ray detector 8 is a position sensitive type, the angular position of the incident point of the diffracted X-ray is detected, and the azimuth angle β of the diffracted X-ray from the sample S is known. α + β is a diffraction angle due to a certain lattice plane of the sample crystal. Therefore, for example, in synchronism with the deflection of the electron beam, when the detector 8 takes the detection output at the azimuth angle α with respect to the incident angle α, the diffracted reflection X-rays on the lattice plane parallel to the sample plane are detected in FIG. it can. The electron beam may be deflected only within a certain angular range so that it scans over the target in the circumferential direction, but in that case, the shape of the deflection signal becomes troublesome, and when the electron beam returns to the start position, The beam needs to be cut. Therefore, it is advisable to rotate and deflect the electron beam itself along the entire circumference of the cone.

【The invention's effect】

The present invention is capable of high-speed angular scanning because it has no mechanical moving parts other than changing the inclination of the sample as necessary, and is durable without problems such as wear and backlash. The X-ray source can easily obtain strong X-rays because the electron irradiation point moves on the target, and unlike the rotating anode X-ray source, the target is fixed, so it is easy to cool and it is similar to a goniometer. Since there is no weight mechanism, the weight of the entire device can be reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view of an embodiment of the present invention, FIG. 2 is a front view of a relevant portion, and FIG. 3 is a front view of a slit. 1 ... Outer casing, 2 ... Electron gun, 3 ... Converging lens, 4 ...
Target, 5 ... Deflection coil, 6 ... X-ray transmission window, 7
...... X-ray incident slit, 8 ... X-ray detector, S ... Sample.

Claims (1)

[Claims] 1. A partially arcuate target is arranged along a circumference having an optical axis of the electron gun as an axis, and an electron beam is bent between the electron gun and the target in a direction in which the electron beam is incident on the target. At the same time, the electron beam deflecting means for deflecting the electron beam so that the target incident point of the electron beam moves on the target along the circumference having the optical axis of the electron gun as the axis, the partial arc-shaped target and the arc center are arranged. A position sensitive type X-ray detector having a partial arc shape is disposed so as to be shared and the arc surface is orthogonal to the optical axis, and the sample is placed on the common arc center of the target and the X-ray detector. An X-ray diffractometer characterized by being positioned.