X-ray or gamma ray systems or devices – Source – Target
Patent
1988-11-15
1990-07-03
Fields, Carolyn E.
X-ray or gamma ray systems or devices
Source
Target
378143, 378127, 378125, H01J 3510
Patent
active
049397621
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an X-ray target for use in X-ray tubes, a method of manufacturing the target, a rotating anode comprising the target, and an X-ray bulb as well as an X-ray tube in which such a rotating anode is built.
The X-ray tube of the present invention is well suited for application to the X-ray CT (the abbreviation of "Computed Tomography") system of medical equipment.
BACKGROUND ART
Examples of an X-ray target for use in an X-ray tube are described in the official gazette of Japanese patent application Publication No. 8263/1972. In this official gazette, there is disclosed the X-ray target of the structure wherein graphite forms a body, and only a part to be irradiated with an electron beam and the vicinity thereof are coated with a tungsten-rhenium alloy. Also, there is disclosed the X-ray target of the structure wherein an interlayer of rhenium is interposed between the graphite body and the tungsten-rhenium alloy coating layer. It is stated that, in the X-ray targets of these structures, the large heat capacity of the graphite protects the tungsten-rhenium alloy coating layer from a thermal excessive load.
The official gazette of Japanese patent application Laid-open No. 202643/1985 discloses the structure of an X-ray bulb which is furnished with an X-ray target. The official gazette of Japanese patent application Laid-open No. 183861/1986 discloses an example of the structure of an X-ray tube which has a built-in X-ray bulb.
Properties required of the X-ray CT system of medical equipment are shortening a diagnosing period of time, clearing a processed image, etc.
For meeting these requirements, the emission amount of X-rays needs to be enlarged by increasing the input of an X-ray tube.
An X-ray target receives an electron beam from a cathode thereby to generate X-rays In generating the X-rays, most of the electron beam is converted into heat, and the X-ray target is heated to a high temperature. The heated temperature of the X-ray target rises with the increase of the input.
The inventors' study has revealed that, in the X-ray target wherein the body is made of graphite, and the part on which an electron beam impinges is coated with the X-ray generating metal material as in the invention described in the official gazette of Japanese patent application Publication No. 8263/1972, the conductivity of heat from the X-ray generating metal coating layer to the graphite body is inferior, so the X-ray generating metal coating layer becomes liable to peel off the graphite body when the input increases.
In this manner, the prior-art X-ray target cannot effectively utilize the large heat capacity which the graphite possesses.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide an X-ray target in which an X-ray generating metal coating layer is less liable to peel off than in the X-ray target described in the official gazette of Japanese patent application Publication No. 8263/1972, so that the input of a tube can be increased more.
Another object of the present invention is to provide a method of manufacturing an X-ray target in which the adhesion between an X-ray generating metal coating layer and a graphite body is favorable, and besides, heat having developed in the X-ray generating metal coating layer can be quickly transmitted to the graphite body.
Still another object of the present invention is to provide an X-ray bulb and an X-ray tube each of which comprises such an X-ray target.
In an X-ray target having a graphite body and an X-ray generating metal coating layer which covers the part of the body to be bombarded with an electron beam and the vicinity thereof, the present invention consists in that a metal interlayer which is nonreactive with graphite and which has a coefficient of thermal expansion substantially equal to those of the graphite and the X-ray generating metal coating layer is formed at the boundary between the graphite body and the X-ray generating metal coating layer, and that the interlayer is caused to percolate int
REFERENCES:
patent: 3579022 (1971-05-01), Hennig et al.
patent: 3894239 (1975-07-01), Braun
patent: 4352041 (1982-09-01), Hubner et al.
Baba Noboru
Fukushima Masatake
Inamura Ichiro
Nakagawa Yusaku
Suwa Masateru
Fields Carolyn E.
Hitachi , Ltd.
Hitachi Medical Corporation
Porta David P.
LandOfFree
Target for X-ray tube as well as method of manufacturing the sam does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Target for X-ray tube as well as method of manufacturing the sam, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Target for X-ray tube as well as method of manufacturing the sam will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1896744