JPH0536368A - Rotation anode x-ray tube and target thereof - Google Patents

Abstract

PURPOSE:To generate X-ray having the desired ray quality without enlarging a device by providing multiple different ring-shape focus surfaces on a target basic material, and selecting the focus surface in response to the use of photographing. CONSTITUTION:Two kinds of doughnut-shape focus surfaces 1, 2 are bonded on a target basic material 3. An anode provided with a target and a part for supporting multiple cathodes are sealed inside of a vacuum case 6. Cathodes 4, 5 are provided opposite to the focus surfaces 1, 2. Electron beam from the cathodes 4, 5 collides with the focus surfaces 1, 2 to generate X-ray. At this stage, the X-ray having the ray quality corresponding to the material of the focus surfaces 1, 2 can be generated. The X-ray having the desired ray quality can be obtained by providing a filter corresponding to each cathode and the material of the focus surfaces. furthermore, a shallow groove is provided in a part to be bonded, and since the focus surface 1 is fitted therein, contrast and image quality is improved without enlarging a device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary anode X-ray tube target, and more particularly to a rotary anode X-ray tube target capable of emitting X-rays of a plurality of types of qualities.

[0002]

2. Description of the Related Art When performing various types of X-ray photography, it is sometimes desired to change the quality of emitted X-rays. Conventionally, in order to generate a plurality of types of X-rays having different radiation qualities from one X-ray tube, as described in Japanese Patent Publication No. 4117814/41, different materials are used in the X-ray emission direction of the X-ray tube. It was done by adding a filter.

[0003]

The above-mentioned prior art has not taken into consideration the problem of withstanding voltage when mounting the filter and the problem of the type of X-ray emitted from the X-ray tube. That is, when the filter is mounted close to the surface of the X-ray tube, a withstand voltage defect may occur, and strengthening the insulation causes a problem that the device becomes large in size. As for the radiated X-rays, a filter is added to obtain X-rays having different wavelength distributions due to the difference in absorptance, so that the line types of X-rays are limited and there is a problem of attenuation of X-ray dose. is there. An object of the present invention is to provide a target for a rotary anode X-ray tube, which can prevent these problems and stably generate X-rays of desired quality without increasing the size of the apparatus.

[0004]

In order to achieve the above object, a rotary anode X-ray tube target is provided with a ring-shaped focal plane made of a plurality of different materials on a target substrate. Furthermore, in the rotating anode X-ray tube,
The target is provided, and a cathode is provided so as to face each of a plurality of focal planes of the target.

[0005]

By providing a plurality of focal planes and a cathode facing each of them, it is possible to generate X-rays having a quality depending on the material of the focal planes. At this time, by providing a filter corresponding to each cathode and the material of the focal plane, X-rays of desired radiation quality can be obtained. Further, in the X-ray tube to which the present invention is applied, the conventional X-ray tube is used.
Although the number of cathodes is larger than that of the X-ray tube, since these cathodes are built in the bulb, the external dimensions of the X-ray tube are the same as the conventional ones. Further, since the structure is similar to that of the conventional X-ray tube, the same reliability can be obtained.

[0006]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view of a target according to an embodiment of the present invention. FIG. 3 is a sectional view of an essential part of an X-ray tube using the target of the present invention. The target of FIG. 1 is a target substrate 3
Two types of donut-shaped focal planes, a focal plane A1 and a focal plane B2, are joined on top of each other. As the target base material 3, molybdenum or graphite is used. The focal planes A1 and B2 are made of different metals, for example, tungsten and molybdenum. Bonding between the focal plane and the target substrate 3 is
When the target substrate 3 is molybdenum, it is forged or brazed, and when the target substrate 3 is graphite, it is CV.
The method D is used. Although the number of focal planes is two in the above description, the number of focal planes may be more than two.

In FIG. 2, an anode having a target and a portion supporting a plurality of cathodes are sealed in a vacuum envelope 6 so as to face each other. As the cathode, facing the focal plane A1 and the focal plane B2 of the target, the cathode A4 and the cathode B5 are provided.
Is provided. The electron beam from the cathode A4 collides with the focal plane A1 to generate X-rays, and the electron beam from the cathode B5 collides with the focal plane B2 to generate X-rays. in this case,
Since the focal plane A1 and the focal plane B2 are made of different materials, X-rays of different quality are generated. When the X-ray tube of the present invention is used to emit X-rays, the focal plane is selected according to the imaging application, and a high voltage is applied between the cathode and the target facing the focal plane. As a result, the quality X that suits the application
Lines are emitted. Further, it is desirable to provide a filter suitable for the material of the focal plane outside the X-ray tube.

FIG. 2 is a sectional view of another embodiment of the present invention. When the target substrate 3 is molybdenum, the inclined surface of the target substrate 3 can be used as it is for the portion corresponding to the focal plane B2 in FIG. 1, so only the focal plane A1 needs to be bonded. In the target of the present invention, a shallow groove is provided in a portion where the focal plane A1 is joined, and the focal plane A1 is fitted into the shallow groove and joined by forging or brazing.

[0009]

According to the present invention, since one X-ray tube can selectively use X-rays of an appropriate line type according to the subject, it is possible to improve image quality by improving contrast and preventing fogging. Become. Further, since the functions of a plurality of devices can be achieved by one device, the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a target according to an embodiment of the present invention.

FIG. 2 is a sectional view of a target according to another embodiment of the present invention.

FIG. 3 is a sectional view of an essential part of an X-ray tube using the target of the present invention.

[Explanation of symbols]

1 Focal plane A 2 Focal plane B 3 Target base material 4 Cathode A 5 Cathode B

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Minoru Kitsuya             Hitachi Co., Ltd., New Juyo 22-1, Kashiwa City, Chiba Prefecture             Inside the Mediaco Kashiwa Plant

Claims (2)

[Claims] 1. A target for a rotary anode X-ray tube, wherein a ring-shaped focal plane made of a plurality of different materials is provided on a target substrate. 2. A rotary anode X-ray tube comprising the target according to claim 1, wherein a cathode is provided facing each of a plurality of focal planes of the target.