JP2001351551A - X-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray tube that can selectively obtain an X-ray source with a specified characteristic X-ray without changing the X-ray tube. SOLUTION: This X-ray tube generates X-rays by the collision of electrons emitted from the filament with a target. The first target T1 formed of a first element, and a second target T2 formed of a second element different from the first element, are provided in one bulb 2. One of two kinds of targets T1, T2 is selected to allow the collision of the electron E.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray tube.

[0002]

2. Description of the Related Art An X-ray tube collides electrons with a target embedded in an anode (anti-cathode), and emits X-rays including characteristic X-rays specific to elements constituting the target.

[0003]

Generally, in X-ray analysis, various characteristic X-rays may be required. However, in the conventional X-ray tube, it is necessary to replace the X-ray tube each time.

Accordingly, an object of the present invention is to provide an X-ray tube capable of selectively obtaining an X-ray source having a predetermined characteristic X-ray without replacing the X-ray tube.

[0005]

In order to achieve the above object, an X-ray tube according to the present invention comprises a first target comprising at least a first element and a second element different from the first element. And a second target formed in one tube, and one of the two types of targets can be selected to collide the electrons.

In a preferred embodiment of the present invention,
More than one type of target is fixed to the tip of one anode, and the tip of the anode moves in a direction intersecting the direction of incidence of the electrons. Thereby, it is possible to select one of the two or more types of targets and cause the electrons to collide. Note that, in the present invention, the anode refers to a so-called counter cathode, and a positive potential is applied to the filament.

[0007] In another preferred embodiment of the present invention, the emission direction of the electrons emitted from or emitted from the filament is selectively deflected. Thereby, it is possible to select one of the two types of targets and cause the electrons to collide.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1A, the present X-ray tube 1 is a horizontal (side window type) X-ray tube, and a filament 3 at a ground potential in a tube 2.
And the anode 4 to which the positive potential is applied are opposed to each other. The X-ray tube 1 emits electrons E emitted from the filament 3.
Is focused on the center of the target T2 embedded in the tip end surface 40 of the anode 4 and collided with the X-ray (primary X-ray).
X-rays are emitted to the outside through an X-ray window 20 (provided for separating vacuum and atmosphere) provided in the tube 2.

The tip surface 40 of the anode 4 is inclined so that the primary X-rays exit from the X-ray window 20.
As shown in FIG. 1B, a plurality of thin plate-shaped targets T1, T2, T3 are embedded in the tip end surface 40 of the anode 4. Each of the targets T1, T2, T3 is:
In the case of line focus, they are provided in parallel so that their longitudinal directions are along the inclined surface. The target T2 is provided at a center position of the anode 4. That is, the target T2 is embedded on the center line T2C in the width direction of the target T2 so that the incident position P of the electron E is set. The targets T1, T3
Are provided slightly apart from each other on the left and right sides of the target T2. Each of the targets T1, T2, T
3 are each made of different elements (for example, iron, copper, and tungsten).

The width 30 of each of the targets T1, T2, T3 is preferably set to 1 mm or more.
The distance Δ from the center line T2C of the target T2 to the adjacent targets T1 and T3 is preferably set to 1 mm or more. The reason is that when the electron E collides with the target T2, a part thereof is scattered and the electron E sometimes collides with the nearby targets T1 and T3.

As shown in FIG. 2A, the anode 4 is fixed to the tube 2 via a support mechanism 5 comprising a bellows 50 and a flange 51 fixed to the tube 2. The driving device 6 composed of a motor or the like swings the anode 4 around the point S as shown in FIG. That is, the anode 4
Moves in a direction R intersecting the incident direction of the electrons E. Thereby, the target T1, T2, T3
One of the two is selected.

First, the second target T2 shown in FIG.
When the electron E collides with the motor 6, the motor 6 shown in FIG.
Do not operate. In this state, when the electron E is emitted from the filament 3, the electron E is transmitted to the second target T
2, and an X-ray having a strong characteristic characteristic X-ray constituting the target T2 is emitted.

On the other hand, when the electron E collides with another target such as the third target T3 in FIG. 1B, the motor 6 shown in FIG.
Is rotated by a predetermined angle θ. In this state, when the electron E is emitted from the filament 3, the electron E collides with the third target T3, and an X-ray having another characteristic X-ray having a higher intensity than that described above is emitted.

FIG. 3 shows a second embodiment. In the second embodiment, a deflection electrode 7 and a voltage controller 8 are provided instead of the support mechanism 5 and the motor 6 of the first embodiment. The deflection electrode 7 changes the direction in which the electrons E emitted from the filament 3 enter the anode 4. A voltage is applied to the deflection electrode 7 by a voltage controller 8, and the applied voltage is controlled.

When the potentials of the upper and lower electrodes 71 and 72 of the deflection electrode 7 are set to the same value, the electrons E travel straight and collide with the target T2. On the other hand, when the upper electrode 71 is set to be positive with respect to the lower electrode 72 by the voltage controller 8, the electrons E
Deflects upward and collides with the first target T1. When the lower electrode 72 is set to be positive with respect to the upper electrode 71 by the voltage controller 8, the electrons E are deflected downward and collide with the third target T3.

The other configuration of the second embodiment is the same as that of the first embodiment. The same or corresponding parts are denoted by the same reference characters, and detailed description and illustration thereof will be omitted.

Although the deflection electrode 7 is provided in the second embodiment, in the present invention, the direction of the electrons E emitted from the filament 3 is changed by swinging the filament 3 instead of the deflection electrode 7. It may be deflected.

The bellows portion 5 of the first embodiment shown in FIG.
Instead of 0, the anode 4 may be provided slidably with respect to the bulb 2 as shown in FIG. The present invention does not limit the shapes of the targets T1, T2, and T3. For example, as shown in FIG.
1, T2 and T3 may be circular. Further, the arrangement of the targets may be arranged on the circumference as shown in FIG. Further, two or more types of targets may be provided, and for example, four types may be provided. Further, the filament may be line-focused or point-focused.

[0019]

As described above, according to the present invention,
Since a plurality of targets are provided on the anode of one X-ray tube, a desired target is selected and collided with electrons, so that a plurality of types of characteristics X can be obtained without replacing the X-ray tube.
One of the lines can be obtained selectively.

[Brief description of the drawings]

FIG. 1A is a front view of an X-ray tube showing a first embodiment of the present invention, and FIG. 1B is a front view of an anode.

FIGS. 2A and 2B are side views of an X-ray tube, respectively.

FIG. 3 is a front view of an X-ray tube according to a second embodiment of the present invention.

FIG. 4A is a side view showing a modification of the X-ray tube, and FIG.
And (c) is a front view of the anode showing another target shape and arrangement.

[Explanation of symbols]

 1: X-ray tube 2: tube 3: filament 4: anode 40: tip surface 5: support mechanism 6: motor (driving machine) 7: deflection electrode E: electron T1 to T3: target

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H05G 1/52 H05G 1/52 B

Claims (5)

[Claims] 1. An X-ray tube for generating X-rays by colliding electrons emitted from a filament with a target, wherein a first target made of a first element and a second element different from the first element are provided. An X-ray tube, wherein a second target consisting of: is provided in one tube, and one of the two types of targets can be selected to collide the electrons. . 2. The method according to claim 1, wherein the two kinds of targets are fixed to a tip of the anode, and the tip of the anode is moved in a direction intersecting with the direction of incidence of the electrons. An X-ray tube in which one of the electrons can be selected to collide with the electrons. 3. The support mechanism according to claim 2, wherein the target supports the anode such that the target is movable in a direction intersecting the direction of incidence of the electrons.
An X-ray tube comprising: a driving device that drives the anode through the support mechanism. 4. The method according to claim 1, wherein an emission direction of the electrons emitted from or emitted from the filament is selectively deflected to select one of the two types of targets to convert the electrons. An X-ray tube that can collide. 5. The target according to claim 4, wherein a deflection electrode for deflecting the emission direction of the electrons is provided between the filament and the anode, and a voltage applied to the deflection electrode is controlled. 1
An X-ray tube in which the electrons are incident.