JPH0917363A - X-ray generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate this adjusting work by automatically adjusting the direction of an electron gun so that an electron beam accurately collides with a target position of an anticathode. SOLUTION: An electron beam (e) emitted from an electron gun 1 is converged by an electromagnetic lens 3, and is collided with an anticathode 4, and X-rays are generated from a surface of the anticathode 4. In such an X-ray generator, an electron beam detecting member 5 is arranged to detect a colliding position of the electron beam (e) to the anticathode 4. Dislocation between a target position of the electron beam (e) to the anticathode 4 and the colliding position is found by a comparing circuit 7 on the basis of a detecting result of the electron beam detecting member 5, and the direction of the electron gun 1 is changed by a driving circuit 8, and the positional dislocation is corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention focuses an electron beam emitted from an electron gun by an electromagnetic lens and collides it with an anticathode to generate X-rays from the surface of the anticathode.
More specifically, the present invention relates to an X-ray generator capable of automatically adjusting the collision position of an electron beam on an anticathode.

[0002]

2. Description of the Related Art FIG. 4 shows the structure of a conventional X-ray generator. Generally, an X-ray generator has an electron gun 1, an anode 2,
The electromagnetic lens 3 and the anticathode 4 are provided, and the electron beam e generated by the electron gun 1 is emitted through the anode 2 and focused by the electromagnetic lens 3 so that the surface of the anticathode 4 is focused. . X-rays are generated from the surface of the anticathode 4 due to the collision of the electron beam e. For example, in the X-ray diffractometer, the sample is irradiated with the X-rays thus generated on the surface of the anticathode 4 to perform the X-ray diffraction measurement.

In the above X-ray generator, the anticathode 4
In order to generate an appropriate amount of X-rays, it is necessary to collide the electron beam e with a predetermined target position (usually the center of the anticathode). However, since the general electron gun 1 is adapted to generate the electron beam e by heating the tungsten wire at a high temperature, the trajectory axis of the electron beam e is slightly deviated due to thermal fluctuation. Therefore, even if the electron gun 1 is mechanically positioned, it is difficult to cause the electron beam e to collide accurately with a target position with respect to the anticathode 4.

[0004]

A current flows through the anticathode 4 due to the collision of the electron beam e. This anticathode 4
The electric current flowing in the area becomes maximum when the electron beam e collides with a predetermined target position. Conventionally, using this phenomenon, an ammeter is attached to the anticathode 4, and the direction of the electron gun 1 is manually adjusted so that the electric current flowing through the anticathode 4 becomes maximum.

However, if the direction of the electron gun 1 is manually adjusted, the work is troublesome and time consuming. Moreover,
When the trajectory of the electron beam e is deviated during operation, the ammeter must be constantly checked to detect this, which is complicated. The present invention has been made in view of such circumstances, and facilitates the adjustment work by automatically adjusting the direction of the electron gun so that the electron beam accurately strikes the target position of the anticathode. The purpose is to

[0006]

In order to achieve the above-mentioned object, the present invention aims at converging an electron beam emitted from an electron gun by an electromagnetic lens and colliding it with an anticathode so that an X-ray is emitted from the surface of the anticathode. In an X-ray generator for generating an electron beam, an electron beam collision position detecting means for detecting a collision position of the electron beam with respect to the anticathode, and an electron beam aiming position with respect to the anticathode based on a detection result of the electron beam collision position detecting means. A correction amount detecting means for obtaining a deviation from the collision position and an electron gun driving means for driving the electron gun so as to correct the position deviation detected by the correction amount detecting means are provided.

[0007]

According to the collision position of the electron beam with respect to the anticathode detected by the electron beam collision position detecting means, the correction amount detecting means obtains the deviation between the aiming position of the electron beam with respect to the anticathode and the collision position. Then, by driving the electron gun by the electron gun driving means to correct the deviation of the collision position of the electron beam with respect to the target position of the anticathode,
The collision position of the electron beam can be automatically matched to the target position of the anticathode.

Here, the electron beam collision position detecting means is arranged at a position equidistant from the center axis of the trajectory of the electron beam impinging on the target position of the anticathode and in the vicinity of the anticathode. It is preferable that a plurality of conductive electron beam detection members are provided. By using this electron beam detection member, the deviation of the collision position of the electron beam with respect to the target position of the anticathode can be detected by the change in the collision area of the electron beam on the electron beam detection member.

Further, a pair of two electron beam detecting members arranged at positions symmetrical with respect to the central axis is arranged, and a plurality of pairs of electron beam detecting members are arranged around the central axis. Then, the correction amount detecting means compares the magnitudes of the currents flowing through the paired electron beam detecting members according to the collision area of the electron beam to determine the target position and the collision position of the electron beam with respect to the anticathode. You may make it obtain | require the gap of. With this configuration, it is possible to obtain the deviation between the aiming position and the collision position of the electron beam with respect to the anticathode with a simple comparison circuit.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an X according to an embodiment of the present invention.
FIG. 2 is a configuration diagram showing the line generator, and FIG. 2 is a perspective view showing a specific configuration of the electron beam detection member shown in FIG. 3 is a circuit block diagram in which the current detection circuit 6, the comparison circuit 7, and the drive circuit 8 shown in FIG. 1 are further embodied.

As shown in FIG. 1, the X-ray generator of this embodiment is similar to the conventional X-ray generator (see FIG. 4) and is equipped with an electron gun 1, an anode 2, an electromagnetic lens 3 and an anticathode 4. There is. Then, the electron beam e generated by the electron gun 1 is emitted through the anode 2 and focused by the electromagnetic lens 3 so that the surface of the anticathode 4 is focused. X-rays are generated from the surface of the anticathode 4 due to the collision of the electron beam e.

Further, an electron beam detecting member 5 as an electron beam collision position detecting means is arranged near the anticathode 4. As shown in FIG. 2, the electron beam detecting member 5 is formed by electrically dividing a cylindrical conductive aperture into an even number (6 divisions in the figure). Therefore, the six electron beam detecting members 5a, 5a ', 5b, 5b', 5c, 5
c'is arranged in a cylindrical shape. These electron beam detecting members 5a to 5c 'can be formed of various conductive members through which a current flows according to the area where the electron beam e collides. However, the magnetic substance is not preferable because it bends the electron beam.

Since the electron beam detecting members 5a to 5c 'are formed by dividing a cylindrical aperture, they are arranged at the same distance from the center axis of the cylinder. Further, the electron beam detecting members 5a to 5c 'are grouped into a plurality of pairs (three pairs in the figure), with two of them as a pair. That is, the electron beam detecting members 5a and 5a ', 5b and 5b', 5c and 5c 'which form a pair are arranged at positions symmetrical with respect to the central axis of the cylinder. Then, each electron beam detection member 5
a to 5c 'are arranged such that the central axis of the cylinder coincides with the trajectory of the electron beam e impinging on the target position of the anticathode 4 (hereinafter, in this embodiment, the center of the anticathode 4). I am doing it.

As shown in FIG. 3, the electron beam detecting members 5a to 5c 'are individually provided with current detecting circuits 6a and 6a, respectively.
a ', 6b, 6b', 6c, 6c 'are connected,
The current values flowing in the electron beam detecting members 5a to 5c 'are detected by the current detecting circuits 6a to 6c'.
The electron beam detecting members 5a-5a 'and 5 which are paired with each other
The current detecting circuits 6a-6a ', 6b-6b' and 6c-6c 'connected to b-5b' and 5c-5c 'respectively,
Each of them is connected to the same comparator circuit 7a, 7b, 7c.

Comparing circuits (correction amount detecting means) 7a to 7c
Compares the detection results of the current detection circuits 6a to 6c 'with each other to form a pair of electron beam detection members 5a-5a' and 5b.
The difference between the current values flowing through -5b 'and 5c-5c' is obtained. Each of the comparison circuits 7a to 7c is connected to the drive circuit 8 (electron gun drive means) of the electron gun 1 and outputs the comparison result to the drive circuit 8. The direction of the electron gun 1 can be changed by driving means such as an electric motor 9. The drive circuit 8 controls the electric motor 9 so that there is no difference between the comparison results, that is, the currents flowing through the electron beam detection members 5a to 5c 'are equal in magnitude.

Next, the operation of the X-ray generator according to this embodiment will be described. The electron beam e emitted from the electron gun 1 and converged by the electromagnetic lens 3 passes through the hollow portions of the electron beam detection members 5a to 5c 'arranged in a cylindrical shape, and the anticathode 4
Colliding with the surface. Here, the electron beam detection members 5a to
The reference numeral 5c 'also has a function of blocking the outer peripheral portion of the electron beam e and correcting the aberration of the electron beam e caused by the distortion of the electromagnetic lens 3 or the like.

Each of the electron beam detecting members 5a to 5c 'includes:
A current having a magnitude corresponding to the collision area of the electron beam e flows. Now, the trajectory of the electron beam e emitted from the electron gun 1 is a cylindrical electron beam detection member 5a-5.
When it coincides with the central axis of c ′, that is, when the electron beam e collides with the center of the anticathode 4, the electron beam e has a substantially equal area on each of the electron beam detecting members 5a to 5c ′.
The outer peripheral part of collides. Therefore, the current values flowing through the electron beam detecting members 5a to 5c 'are substantially equal to each other, which are detected by the current detecting circuits 6a to 6c' and output to the comparing circuits 7a to 7c. The comparison result of the current values in each of the comparison circuits 7a to 7c becomes zero, so that the drive signal is not output from the drive circuit 8 and the electron gun 1 is kept in the same direction.

The trajectory of the electron beam e emitted from the electron gun 1 is a cylindrical electron beam detecting member 5.
When they do not coincide with the central axes of a to 5c ', that is, when the electron beam e collides with the position deviated from the center of the anticathode 4, the paired electron beam detection members 5a-5a are formed depending on the deviated direction. There is a difference in the collision area of the electron beam e between ', 5b-5b' and 5c-5c '. Then, a larger current flows through the electron beam detection member having a larger collision area of the electron beam e than the other electron beam detection member. Each of the current detection circuits 6a to 6c 'detects the value of the current flowing through these electron beam detection members 5a to 5c'. Paired electron beam detection members 5a-5a ', 5b
The current values flowing through -5b 'and 5c-5c' are input to the same comparison circuits 7a to 7c, and the difference between the current values is output to the drive circuit 8 as a comparison result.

In this embodiment, since the three pairs of electron beam detecting members 5a-5a ', 5b-5b', 5c-5c 'are arranged around the orbit of the electron beam e, the difference in the three current values is obtained. Is output to the drive circuit 8. The drive circuit 8 moves the electron gun 1 in a direction in which the difference between these current values is zero, that is, in a direction in which the electron beam e collides with the center of the anticathode 4. Thus, the electron beam e can be automatically made to strike the center of the anticathode 4. Further, even when the collision position of the electron beam e is displaced during operation, the displacement can be detected by the current change of the electron beam detection members 5a to 5c ', so that the direction of the electron gun 1 is automatically corrected. Therefore, the proper collision state of the electron beam e can be maintained.

The present invention is not limited to the above embodiment. For example, it goes without saying that the X-ray generator of the present invention can be applied not only to measuring devices such as X-ray diffractometers but also to various industrial equipment utilizing X-rays.

[0021]

As described above, according to the X-ray generator of the present invention, the direction of the electron gun can be automatically adjusted so that the electron beam collides accurately with the target position of the anticathode. Adjustment work becomes easy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an X-ray generator according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a specific configuration of the electron beam detection member shown in FIG.

FIG. 3 is a circuit block diagram further embodying the current detection circuit, the comparison circuit, and the drive circuit shown in FIG.

FIG. 4 is a configuration diagram showing a conventional X-ray generator.

[Explanation of symbols]

1: Electron gun 2: Anode 3: Electromagnetic lens 4: Anticathode 5a, 5a ', 5b, 5b', 5c, 5c ': Electron beam detection member 6a, 6a', 6b, 6b ', 6c, 6c': Current Detection circuit 7a, 7b, 7c: Comparison circuit 8: Drive circuit 9: Electric motor

Claims (3)

[Claims] 1. An X-ray generator for generating an X-ray from the surface of the anticathode by converging an electron beam emitted from an electron gun with an electromagnetic lens and colliding with the anticathode. An electron beam collision position detecting means for detecting the collision position of the electron beam, and a correction amount detecting means for obtaining a deviation between the aim position and the collision position of the electron beam with respect to the anticathode based on the detection result of the electron beam collision position detecting means, An X-ray generator comprising: an electron gun driving unit that drives the electron gun so as to correct the positional deviation detected by the correction amount detecting unit. 2. The electron beam collision position detecting means is arranged at a position equidistant from the center axis of the trajectory of the electron beam impinging on the target position of the anticathode and in the vicinity of the anticathode. The X-ray generator according to claim 1, wherein the X-ray generator comprises a plurality of conductive electron beam detecting members provided. 3. A pair of two electron beam detecting members arranged at symmetrical positions with respect to the central axis, a plurality of pairs of electron beam detecting members arranged around the central axis, and the correction amount detecting means. Wherein the difference between the aim position and the collision position of the electron beam with respect to the anticathode is obtained by comparing the magnitudes of the currents flowing through the paired electron beam detection members. 2. The X-ray generator described in 2.