JPH05135719A - Anode structure for x-ray tube - Google Patents

Abstract

PURPOSE:To provide the anode structure of an X-ray tube preventing an anode target from being peeled from a support base, improving heat conduction, and improving the cooling by the heat conduction from the anode target to the target support base. CONSTITUTION:An anode target 9 is provided on a target support base 8 to form the anode structure 7 of an X-ray tube, and the middle section between the anode target 9 portion and the target support base 8 portion is made of an inclined function material having a region 10 where the contents of the metal material of the anode target 9 portion and the metal material of the target support base 8 portion are gradually changed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an anode assembly for an X-ray tube.

[0002]

2. Description of the Related Art Conventionally, for example, a fixed anode type X-ray tube is constructed as shown in FIG. 3, in which a cathode body 2 and an anode body 3 are arranged to face each other in a vacuum envelope 1. In the anode assembly 3, a tungsten target support 5 is fixed to the tip end surface of a copper target support base 4 by embedding or brazing.

During operation, thermoelectrons 6 are emitted from the cathode structure 2, and these thermoelectrons are accelerated by the potential difference between the cathode structure 2 and the anode structure 3 and collide with the anode target 5 to generate X-rays. ..

[0004]

However, the following disadvantages occur in the X-ray tube as described above.

That is, during operation, the anode target 5 is heated to a high temperature, but the anode target 5 is targeted by the difference in thermal expansion between the tungsten of the anode target 5 and the copper of the target support substrate 4. It may come off from the supporting substrate 4.
Generally, the target support base 4 has a function of transmitting heat generated in the anode target 5 to the outside by heat conduction and cooling the anode target 5, but the anode target 5 and the target support base 4 are If peeling occurs between the two, the heat conduction becomes small and the anode target 5 becomes higher in temperature, and in some cases, the anode target 5 may melt.

The present invention solves the above-mentioned inconveniences and prevents the anode target from peeling off from the anode substrate, and the heat conduction is improved so that the anode target is transferred to the target supporting substrate. Cooling due to heat conduction is also improved X
It is intended to provide an anode assembly for a wire tube.

[0007]

According to the present invention, there is provided an anode structure for an X-ray tube, wherein the anode target is provided on a target supporting substrate, and the anode structure comprises an anode target portion and a target. An anode of an X-ray tube composed of a functionally graded material having a region in which the content of the metal material of the anode target portion and the content of the metal material of the target support substrate portion gradually changes in the middle of the target support substrate portion. It is a structure.

[0008]

According to the present invention, the coefficient of thermal expansion gradually changes between the target support substrate and the anode target.
Therefore, since a rapid difference in thermal expansion cannot occur, the anode type
The get does not come off from the target support substrate.
Also, because there is no clear boundary between the two parts,
The heat conduction is not hindered, and the cooling due to the heat conduction from the anode target to the target support substrate is also improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

Taking a fixed anode type X-ray tube as an example, the anode structure according to the present invention is constructed as shown in FIG. 1, and the same parts as those in the conventional example (FIG. 3) are designated by the same reference numerals.
A cathode assembly 2 and an anode assembly 7 are provided in a vacuum envelope (not shown).
And are arranged so as to face each other. The anode assembly 2 is composed of a copper (Cu) target support base 8 and a tungsten (W) anode target 9 fixed to the tip surface of the target support base 8 by brazing or the like. In this case, in the middle of the anode target 9 part and the target support base 8 part,
Region 10 in which the content of tungsten in the anode target 9 portion and the content of copper in the target supporting substrate 8 portion gradually change
It is composed of a functionally graded material having.

Here, the functionally graded material will be described.
When the two materials A and B are joined together, the advantages of the two can be utilized, but there is a drawback that they tend to bend or peel off due to the difference in thermal expansion coefficient. However, the functionally graded material gradually eliminates such a defect by gradually changing the material from A to B at the boundary surface. For details, see the magazine “Industrial materials”.
Volume 38 Number 12, Number 14 (October 1990, 11
Monthly issue). In addition to the tungsten, the anode target 9 may use a heavy metal such as rhodium or molybdenum depending on the X-ray output to be obtained. (Other embodiments)

FIG. 2 is a sectional view showing an anode assembly of an X-ray tube according to another embodiment of the present invention. That is, FIG. 2 shows an anode structure of a so-called rotary anode type X-ray tube.
Reference numeral 1 is a substantially umbrella-shaped target support base 12 made of molybdenum.
And an anode target 13 made of tungsten, which is fixed to the light slope of the peripheral portion by brazing.
In this case, as in the above-described embodiment, the region 14 in which the contents of tungsten and molybdenum gradually change is provided in the middle of the anode target 13 portion and the target support base 12 portion.
It is composed of a functionally graded material having the following, and the same effect as that of the above-mentioned embodiment can be obtained.

[0013]

According to the present invention,

Therefore, the coefficient of thermal expansion also changes gradually.
As a result, a rapid difference in thermal expansion cannot occur, so that the anode target does not peel off from the anode substrate. Further, since there is no clear boundary at the joint between the two, heat conduction is not hindered, and cooling by heat conduction from the anode target to the anode substrate is also improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an anode assembly of an X-ray tube according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an anode assembly of an X-ray tube according to another embodiment of the present invention.

FIG. 3 is a sectional view showing an anode assembly of a conventional X-ray tube.

[Explanation of symbols]

7, 11 ... Anode structure, 8, 12 ... Target support base,
9, 13 ... Anode target, 10, 14 ... Region.

Claims (1)

[Claims] 1. An anode structure for an X-ray tube, wherein an anode target is provided on a target supporting substrate, wherein the anode structure comprises the anode target portion and the target supporting substrate portion. An X-ray tube characterized by comprising a functionally graded material having a region in which the content of the metal material of the anode target portion and the content of the metal material of the target supporting base portion gradually changes. Anode structure.