JP2002352756A - Rotating anode x-ray tube device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotating anode X-ray tube device equipped with a rotating anode X-ray tube having a recoil electron trap, which can deal with high output power, without enlarging the device. SOLUTION: This device comprises the rotating anode X-ray tube 12 and a tube container 11 for housing this rotating anode X-ray tube 12. The rotating anode X-ray tube 12 comprises a cathode 14, arranged inside a vacuum outer periphery envelope 13, an anode target 17 for emitting a X-ray, an inner rotor 19 rotating integrally with the anode target 17, a fixed body 22 for rotatably supporting the anode target 17 with the rotor 19, and a recoil electron trap 28 arranged in between the cathode 14 and the anode target 17. The recoil electron trap 28 is coupled mechanically with a part of the vacuum envelope 13, and the trap 28 is formed to be solid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rotating anode type X-ray tube apparatus.

[0002]

2. Description of the Related Art A rotating anode type X-ray tube apparatus uses a rotating anode type X-ray tube as a source of X-rays. And emits X-rays from the anode target. The anode target is rotatably supported by a rotating mechanism, and the rotating mechanism includes a rotating body and a fixed body to which the anode target is connected. A bearing is provided between the rotating body and the fixed body constituting the rotating mechanism.

[0003] Rolling bearings such as ball bearings, or spiral grooves formed on the bearing surface, and gallium (Ga) or gallium-indium-tin (Ga-In-Sn) alloys are used as bearings for the rotating mechanism. Dynamic sliding bearings in which a liquid crystal lubricant is filled in a bearing gap are used.

[0004]

In the case of a rotating anode X-ray tube, electrons emitted from the cathode are accelerated and focused by a potential gradient between the cathode and the anode target.
A focus serving as an X-ray source is formed on the anode target with an energy of 150 keV. When high-energy electrons collide with the focus on the anode target, the electrons are rapidly decelerated and X-rays are emitted from the anode target.

[0005] A small portion of the kinetic energy of electrons colliding with the anode target of about 1% is converted into X-rays.
The remaining energy is converted to heat, causing the anode target to heat. The heating of the anode target is performed when the output of the electron beam is increased to increase the emission amount of X-rays, or when X-rays are emitted frequently, in order to improve the performance of the rotating anode X-ray tube. This is an obstacle to the continuous emission of wires over a long period of time.

Also, about 50% of the electrons colliding with the anode target are scattered backward. Backscattered electrons (hereinafter referred to as
Recoil electrons) once move away from the surface of the anode target. Then, the potential gradient between the cathode and the anode accelerates toward the anode target, and most of the recoil electrons collide again with the surface of the anode target away from the focal point. When the recoil electrons re-collide with the anode target, the anode target heats up or becomes unused X-rays (hereinafter, out-of-focus X-rays).
(Referred to as a line), and the clarity of the X-ray image is impaired.

[0007] As described above, recoil electrons only heat the anode target and do not contribute to the generation of usable X-rays, hindering the performance enhancement of the X-ray tube.

[0008] Therefore, there is a method of reducing the heating of the anode target by the recoil electrons by disposing a shield structure for capturing the recoil electrons between the cathode and the anode target (see US Pat. 11-510
No. 955).

In these methods, the shield structure is composed of a relatively thin metal wall. Further, the shield structure has a structure in which a wall surface opposite to a surface impacted by recoil electrons is cooled by a cooling medium. Then, the heat of the shield structure generated by the impact of the recoil electrons is transferred to the cooling wall surface by heat conduction, and is immediately exchanged with the cooling medium.

In the above method, when the heat generated in the shield structure exceeds the heat exchange capacity of the cooling medium, the temperature of the metal wall increases. If this temperature rise is large, the surface of the metal wall will melt. In addition, an undesired gas is generated from the metal wall into the vacuum tube, thereby lowering the withstand voltage performance.

Therefore, it is difficult to apply the method using the shield structure to a high-output X-ray imaging apparatus such as a CT apparatus. For example, CT with continuous 72 kW output
When applied to a device, the percentage of captured recoil electrons is 80
%, About 29 kW of heat needs to be transferred directly to the cooling medium. However, in the case of the current CT device, the maximum cooling performance of the oil cooling device is less than 10 kW, so that it is difficult to employ a shield structure.

Japanese Patent Application Laid-Open Publication No. 2000-200695 discloses a heat transfer device having a shape including a hole for bonding an X-ray transmission window on a part of the outer surface of a vacuum envelope in order to capture recoil electrons. A method for providing a storage assembly is shown. This heat storage assembly has a structure in which a heat exchange chamber is provided therein, and a cooling medium flows in the heat exchange chamber to cool the heat storage assembly.

[0013] The method using the heat storage assembly includes a cooling medium inlet for flowing a cooling medium into the heat exchange chamber.
It is necessary to provide it near the radiation window, and the gap between the tube container and the X-ray tube becomes wider than before. In addition, it is necessary to add a cooling medium passage for flowing the cooling medium into the heat exchange chamber, and the number of cooling medium passages connected to the outside of the tube container, for example, the number of hoses becomes larger than before. As a result, the overall structure of the X-ray tube device becomes large, and the size of an X-ray imaging device or the like on which the X-ray tube device is mounted is increased because it is necessary to avoid interference with the X-ray tube device.

The present invention solves the above-mentioned drawbacks and provides a rotary anode type X-ray tube device having a rotary anode type X-ray tube having a recoil electron trap capable of coping with high output and preventing an increase in size of the device. The purpose is to do.

[0015]

According to the present invention, there is provided a rotary anode type X-ray tube, and a tube container for accommodating the rotary anode type X-ray tube, wherein the rotary anode type X-ray tube has a vacuum envelope. A cathode disposed in a vessel, an anode target that emits X-rays by irradiation of an electron beam generated by the cathode, a rotating body that rotates integrally with the anode target, and the anode target can be rotated together with the rotating body. In a rotating anode type X-ray tube device having a fixed body constituting a rotating mechanism for supporting the battery and a recoil electron trap disposed between the cathode and the anode target, the recoil electron trap is It is characterized in that it is mechanically connected to a part of the envelope and is solidly formed.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the sectional view of FIG. Reference numeral 11 denotes a tube container, and an output window 11 for outputting X-rays to a side wall portion 11a on the right side in the figure.
1a is provided. A first opening 11 for introducing a cooling medium, for example, insulating oil, into the center of the front wall portion 11b in the upper part of the figure.
1b is provided, and a second opening 111c for leading out the insulating oil is provided below the left side wall portion 11c in the figure.

A rotating anode X-ray tube 12 is housed in a tube container 11. The rotating anode X-ray tube 12 has an outer portion formed of a vacuum envelope 13. The vacuum envelope 13 has a large diameter portion 13a having a large diameter and a small diameter portion 13b having a small diameter.
It is composed of The front surface of the large diameter portion 13a is formed by a substantially flat front wall 13c, and the rear surface of the small diameter portion 13b is sealed by a sealing ring 13d. An output window 131 for outputting X-rays is provided on a side wall portion of the large-diameter portion 13a. The cathode 14 is disposed at the center of the front wall 13c, for example, at a position displaced in the radial direction from the tube axis.

For example, a cylindrical support ring 15 is airtightly joined to the front wall 13c of the vacuum envelope 13, and a support member 16 is airtightly joined to the inside of a bent portion 15a bent inside the upper end of the support ring 15. The cathode 14 is fixed to the support member 16. Further, a disk-shaped anode target 17 is arranged so as to face the cathode 14.

The anode target 17 has a target layer 17 a for emitting X-rays on the surface on the side of the cathode 14, and is fixed to the upper end of the inner rotating body 19 in the figure by a nut 18. The inner rotating body 19 is cylindrical, and a cylindrical outer rotating body 20 is joined to the outer peripheral surface thereof.

The outer rotating body 20 has a part of an upper end portion joined to the inner rotating body 19 and a lower part thereof has an inner rotating body 19.
And a gap is provided therebetween. A space 21 is provided in the axial direction at a central portion inside the inner rotating body 19, and a fixed body 22 is fitted in the space 21. The opening at the lower end in the figure of the inner rotating body 19 is sealed with a thrust ring 23.

The fixed body 22 constitutes a rotating mechanism for rotatably supporting the anode target 17 together with the inner rotating body 19 and the outer rotating body 20. Lower end 22 of fixed body 22
Reference numeral 1 extends through the thrust ring 23 and the sealing ring 13 d to the outside of the vacuum envelope 13. The fixed body 22 is provided with a large-diameter portion 22 a having a large outer diameter at an intermediate portion adjacent to the thrust ring 23. The illustrated upper surface of the large-diameter portion 22a faces the step surface of the inner rotating body 19, and the large-diameter portion 22a
Is opposed to the thrust ring 23. The fixed body 22 has its annular step located outside the vacuum envelope 13 supported by an abutting annular projection 24 a projecting upward in the figure from the fixing member 24 and fixed by tightening with the screw 10. .

The peripheral portion 24b of the fixing member 24 spreads flat, and a part of the peripheral portion 24b is provided with a cooling medium through hole 24c through which insulating oil passes. The fixing member 24 is fixed to a pot-shaped holding member 25, and the outer end of the holding member 25 is
It is fixed to.

At the center of the front wall 13c of the vacuum envelope 13, a holding structure 26 constituting a part of the vacuum envelope 13 is hermetically joined. The holding structure 26 is provided with a hole 26a having an opening on the side of the front wall portion 11b of the tube container 11 along the tube axis. The lower end of the pipe 27 is inserted into the hole 26a, and the upper end of the pipe 27 is connected to the first opening 111b of the tube 11 into which a cooling medium, for example, insulating oil is introduced.

At this time, as shown by an arrow Y1, a cooling circuit is formed in the tube vessel 11. For example, a cooling medium introduced from the first opening 111b, for example, insulating oil,
It descends inside the pipe 27, rises outside the pipe 27 inside the hole 26 a, further passes through the gap between the tube container 11 and the vacuum envelope 13, passes through the cooling medium through hole 24 c of the fixing member 24, and It is derived from the opening 111c.

A recoil electron trap 28 is fixed to, for example, a lower end portion of the holding structure 26 with a nut 29, and the holding structure 26 and the recoil electron trap 28 are electrically, thermally, or mechanically connected, for example. . In this case, a part of the nut 29 has entered the upper space 19 a of the inner rotating body 19. The recoil electron trap 28 is formed to have a predetermined width, and extends beyond the path of the electron beam e from the cathode 14 to the anode target 17 to the end thereof.
The recoil electron trap 28 is composed of a thick plate portion 28a having a large thickness fixed to the holding structure 26 and a thin plate portion 28b having a small thickness continuing outward from the thick plate portion 28a.

A step 28c is provided on the surface of the thick plate portion 28a on the side of the anode target 17 in such a direction that a portion outside the nut 18 fixing the anode target 17 approaches the anode target 17. I have. Thin plate part 28b
The electron beam through hole 28 which is a passage for the electron beam e.
c is provided. The recoil electron trap 28 is not provided with a heat exchange chamber for cooling using a cooling medium or the like, for example, a cooling passage, and the portion of the through hole through which the holding structure 26 passes and the electron beam through hole 28c Except for the portion described above, the thickness portions, for example, the thick plate portion 28a and the thin plate portion 28b, sandwiched between the surface located on the cathode 14 side and the surface located on the anode target 17 side are formed substantially solid.

A radial dynamic sliding bearing is formed between the inner rotating body 19 and the fixed body 22, for example, between the inner circumferential surface of the inner rotating body 19 and the outer circumferential surface of the fixed body 22. Further, between the upper surface of the large-diameter portion 22a of the fixed body 22 and the step surface of the inner rotating body 19, and between the large-diameter portion 22a
And a thrust ring 23, a thrust dynamic sliding bearing is formed in the thrust direction. These dynamic pressure type sliding bearings are formed, for example, by forming a spiral groove on one of the opposing surfaces and filling the spiral groove and the bearing gap with a liquid metal lubricant. Also, the small diameter portion 13b of the vacuum envelope 13
A stator 30 for generating a rotating magnetic field is arranged outside the circumstance.

In the above configuration, when the rotating anode type X-ray tube apparatus enters an operating state, a current is supplied to the coil of the stator 30 to generate a rotating magnetic field. By the rotating magnetic field,
The inner rotating body 19 and the outer rotating body 20 rotate, and the anode target 17 rotates integrally therewith. In this state,
The electron beam e emitted from the cathode 14 is applied to the anode target 17.
The anode target 1 is caused to collide with the upper target layer 17a.
7 emits X-rays. The X-ray is output to the outside through the output window 131 of the vacuum envelope 13 and the output window 111a of the tube container 11, as indicated by an arrow Y2.

At this time, recoil electrons scattered backward from the anode target 17 are captured by the recoil electron trap 28. The temperature of the recoil electron trap 28 rises due to the capture of the recoil electrons. This heat is transmitted to the vacuum envelope 13 by heat radiation or the like and is conducted to the insulating oil flowing outside the vacuum envelope 13 or is conducted to the insulating oil flowing inside the holding structure 26 and is radiated.

As described above, the recoil electron trap 28 is heated with a high power in a relatively short time when X-rays are irradiated. This heat is transmitted to and accumulated in the entire recoil electron trap 28 by heat conduction, and the temperature of the entire recoil electron trap 28 rises. The heat of the recoil electron trap 28 is gradually transmitted to insulating oil or the like by heat radiation or heat conduction, and is gradually dissipated during a relatively long time during which X-ray irradiation is interrupted.

According to the above configuration, most of the recoil electrons are captured by the recoil electron trap 28. Therefore, recoil of the recoil electrons with the anode target 17 is reduced, and the heating of the anode target 17 is suppressed. Also, out of focus X
The emission of the line is also reduced, and the decrease in the clarity of the X-ray image is prevented. In addition, since the tip of the recoil electron trap 28 on the output window 131 side and the outer end of the anode target 17 are substantially at the same position in the radial direction about the tube axis, the vacuum envelope 13
Does not grow.

The recoil electron trap 28 is cooled by insulating oil flowing in the tube 11 and the holding structure 26. Since such a structure is existing, there is no need to newly provide a cooling path for cooling the recoil electron trap 28, and the X-ray tube device does not increase in size. As a result, a rotating anode X-ray tube having a recoil electron trap capable of handling high output is obtained, and the size of the rotating anode X-ray tube device is prevented from increasing.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In FIG. 2, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and redundant description is partially omitted.

In the case of this embodiment, the electron beam through hole 2
8c has a cross-sectional shape spreading like a bowl on the cathode 14 side, and the opening on the cathode 14 side is formed larger than the opening on the anode target 17 side. An extension 281 is provided at the tip of the recoil electron trap 28 far from the side fixed to the holding structure 26, for example, to bend substantially at right angles to the anode target 17 side. The extension part 281 is located between the anode target 17 and the vacuum envelope 13, for example, the output window 131, and is provided with an X-ray through-hole 282 serving as an X-ray passage. Except for the X-ray through hole 282, the extension 281 has a solid thickness portion sandwiched between the surface on the anode target 17 side and the surface on the output window 131 side.

According to this configuration, X-rays shifted laterally from the desired traveling direction are shielded by the recoil electron trap 28. As a result, irradiation to the output window 131 is prevented, and heating of the output window 131 is suppressed.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In FIG. 3, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and redundant description is partially omitted.

A first opening 111b and a second opening 111c are provided in a front wall portion 11b of the tube container 11, and
A partition wall 31 that divides a space between the front wall portion 11b and the rotary anode X-ray tube 12 into two is provided.

A cylindrical internal rotator 32 is integrally provided inside the inner rotator 19, and the opening at the lower end of the inner rotator 32 is sealed with the thrust ring 23, and the opening at the upper end of the inner rotator 32 is shown. Is sealed with a sealing ring 33. The fixed body 22 is fitted in the inner space 32 a of the internal rotating body 32. The fixed body 22 constitutes a rotation mechanism that rotatably supports the anode target 17 together with the internal rotating body 32 and the like. A second large-diameter portion 34 is formed in a portion adjacent to the sealing ring 33, and The upper end extends to above the partition 31 and is fixed to the partition 31. For example, partition 3
1 A fixing member 35 is attached to a central through hole,
The annular stepped portion 36 of the fixed body 22 is abutted and supported by an annular projecting end 35 a of the fixing member 35 projecting downward in the figure, and is fixed by tightening with a nut 37.

Further, a plurality of holes 38 penetrating the fixing member 35 and the partition wall 31 surrounding the fixing body 22 are provided. A cylindrical guide member 39 extending in the direction of the rotary anode X-ray tube 12 is provided outside the hole 38 on the lower surface of the partition wall 31 located on the rotary anode X-ray tube 12 side.

A cylindrical joining member 40 is hermetically joined to the fixed body 22 on the outer peripheral surface of the annular step portion 36 of the fixed body 22. Further, a fixing ring 41 is provided at the center of the vacuum envelope 13.
The recoil electron trap 2 is provided between the inner surface of the bent portion 41 a bent inside the upper end of the fixing ring 41 and the outer peripheral surfaces of the cylindrical joining member 40 and the fixed body 22.
8 are joined.

The recoil electron trap 28 comprises, for example, a cylindrical portion 42a and a horizontal portion 42b extending from a lower end of the cylindrical portion 42a in a predetermined width in a radial direction around the tube axis. The cylindrical portion 42a of the recoil electron trap 28, for example, the thickness portion sandwiched between the outer peripheral surface and the inner peripheral surface, and the horizontal portion 42b, for example, the thickness portion sandwiched between the cathode upper surface and the anode target lower surface, , Electron beam through hole 2
Except for the portion 8c, all are substantially solid. In addition, a gap is provided between the lower part of the cylindrical portion 42 a of the recoil electron trap 28 in the figure and the outer peripheral surface of the fixed body 22.

A through hole 43 penetrating from the upper end surface to the lower end surface is formed in the fixed body 22 along the tube axis. The opening 43 a at the upper end of the through hole 43 in the drawing is connected to the first opening 11 through the tube 44.
1b, the opening 43b at the lower end of the drawing is
Open inside.

At this time, as shown by an arrow Y1, the pipe 44, the through hole 43 of the fixed body 22, the medium through hole 24c of the fixed member 24, the tube container 11 and the vacuum envelope 13 from the first opening 111b. Clearance, cylindrical guide member 39 and recoil electron trap 2
8, a circulation path for the cooling medium is formed which sequentially connects the gap 8, the hole 38 of the partition wall 31, and the second opening 111c.

According to the above configuration, the recoil electron trap 28 constitutes a part of the vacuum envelope 13. Therefore, the insulating oil flows in direct contact with the recoil electron trap 28, and the contact area between the insulating oil and the recoil electron trap 28 is increased, thereby improving the cooling efficiency. Further, a cylindrical guide member 39 is arranged so as to surround the recoil electron trap 28, and a passage of insulating oil between the recoil electron trap 28 and the cylindrical guide member 39 is narrowed. In this case, the flow speed of the insulating oil flowing between the recoil electron trap 28 and the cylindrical guide member 39 is increased, and the cooling efficiency is improved. Further, since the through holes 43 in the fixed body 22 are formed in a straight line, the flow rate of the insulating oil flowing through the through holes 43 can be increased, and the cooling efficiency is improved.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In FIG. 4, parts corresponding to those in FIGS. 1 to 3 are denoted by the same reference numerals, and redundant description is partially omitted.

A second opening 111c is provided in the right side wall portion 11a of the tube container 11 in the drawing, and the rear surface of the small diameter portion 13b of the vacuum envelope 13 is sealed by extending the small diameter portion 13b as it is. . The internal rotating body 32 is formed in a bottomed cylindrical shape having a bottom at the bottom in the figure, and an opening at the top in the figure is sealed with a sealing ring 33. The fixed body 22 is fitted in the internal space of the inner cylindrical body 32, and a large-diameter portion 34 is formed in a portion of the fixed body 22 adjacent to the sealing ring 33. A hole 51 is formed at the center of the fixed body 22 in the pipe axis direction, and a pipe 52 is inserted into the hole 51. The upper end opening 52a of the pipe 52 is connected to the first opening 111b, and the lower end opening 52b opens near the bottom of the hole 51 of the fixed body 22. Further, a portion of the inner rotating body 19, for example, a portion located between the inner rotating body 32 and the inner rotating body 32, is formed of a tubular member 53 having a lower thermal conductivity than the other inner rotating body 19.

In the case of the above-described configuration, as shown by the arrow Y1, the pipe 44, the inside of the pipe 52, the outside of the pipe 52 inside the hole 51, the hole 38 of the partition wall 31,
The gap between the cylindrical guide member 39 and the recoil electron trap 28, the gap between the tube container 11 and the vacuum envelope 13, the second opening 111c
Are sequentially connected to each other. In the case of this configuration, the dynamic pressure type sliding bearing is the internal rotating body 3
2 and the fixed body 22.

According to the above-described configuration, a part of the inner rotating body 19 is formed by the cylindrical member 53 having low thermal conductivity. Therefore, the heat transmitted from the anode target 17 to the internal rotating body 32 is reduced, and the temperature rise of the bearing portion is suppressed.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

A protruding portion 61 is formed on the right side of the front wall portion 11b of the tube container so as to protrude outward. The second opening 11 through which the insulating oil flows out above the side wall portion 11c on the left side of the drawing.
1c is provided, and a first opening 111b into which insulating oil is introduced is provided below. Most of the front wall 13c of the vacuum envelope 13 has a recoil electron trap 2
8. A concave portion 62 is formed in the center portion of the recoil electron trap 28 on the anode target 17 side, and a portion of the nut 18 for fixing the anode target 17 is inserted into the concave portion 62, for example.

The cross-sectional shape of the electron beam through hole 28c of the recoil electron trap 28 is such that the side of the cathode 14 expands like a bowl and the opening thereof is larger than the opening of the anode target 17 side. An extension 281 is provided at an end of the recoil electron trap 28, for example, so as to be bent substantially at a right angle toward the anode target 17. The extension part 281 is located between the anode target 17 and the vacuum envelope 13, for example, the output window 131, and is provided with an X-ray through-hole 282 serving as an X-ray passage. The extension 281 has a solid thickness portion between the surface on the anode target 17 side and the surface on the output window 131 side except for the X-ray through hole 282.

A cylindrical support ring 15 is hermetically joined to the recoil electron trap 28. The upper portion of the support ring 15 is located within the protrusion 61 of the tube container 11, and the support member 16 is fixed to the inner surface of the bent portion 15 a bent inside the upper end of the support ring 15. The cathode 14 is fixed.

In the case of the above configuration, as shown by the arrow Y1, the first opening 111b and the medium through hole 2 of the fixing member 24 are formed.
4c, a cooling medium circulation path connecting the gap between the tube container 11 and the vacuum envelope 13 and the second opening 111c in this order is formed.

According to this configuration, the recoil electron trap 28
Forms a part of the front surface of the large-diameter portion 13a of the vacuum envelope 13, and the area exposed in the vacuum vessel is large. Therefore, a good heat radiation effect can be obtained with a large amount of heat conduction to the insulating oil. Further, the X-rays deviated in the lateral direction from the traveling direction are shielded by the recoil electron trap 28, irradiation to the output window 131 is prevented, and the heating of the output window 131 is suppressed.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. 6, parts corresponding to those in FIG. 5 are denoted by the same reference numerals, and redundant description is partially omitted.

In this embodiment, the recoil electron trap 28 constitutes the right part of the front wall 13c of the vacuum envelope 13 in the drawing. A cylindrical cooling path structure 66 for forming a cooling medium path is disposed between the inner surface of the projecting portion 61 of the tube container 11 and the support ring 15. The cooling path assembly 66 is configured such that the opening 66a on the recoil electron trap 28 side is larger than the opening 66b on the cathode side.
A substantially annular and narrow passage for insulating oil is formed between the recoil electron trap 6 and the recoil electron trap 28 and between the cooling path structure 66 and the support ring 15.

According to the above-described structure, as shown by the arrow Y1, the first opening 111c, the medium through-hole 24c of the fixing member 24, the gap between the tube container 11 and the vacuum envelope 13, the cooling path structure 66. And a gap between the recoil electron trap 28, a gap between the cooling path structure 66 and the support ring 15, and a cooling medium circulation path connecting the second opening 111 c in this order.

According to this configuration, since the gap between the cooling path assembly 66 and the recoil electron trap 28 is narrow, the flow velocity is increased, and the radiation efficiency is improved. Further, the X-rays shifted laterally from the desired traveling direction are shielded by the recoil electron trap 28, and the heating of the output window 131 is suppressed. In addition, recoil electron trap 2
8, the distance between the heating section and the flow path of the insulating oil is short, and the heat radiation efficiency is improved.

Next, another embodiment of the present invention will be described with reference to FIG. 7 in which one side of the tube axis of the recoil electron trap is extracted.

In this embodiment, for example, the recoil electron trap 28 is fixed with a nut 72 to a fixed body 71 constituting a rotating mechanism for supporting the anode target. A plurality of grooves 73 are formed, for example, in a circular arc shape concentrically with the tube axis m over the entire width thereof, for example, on the cathode side surface of the thick plate portion 28a located on the fixed body 71 side of the recoil electron trap 28, for example. . Further, a blackened film 74 is formed on the surface on the cathode side where the groove 73 is formed in order to enhance the heat radiation effect. In addition, in the vicinity of the electron beam through hole 28c, for example, a region 75a surrounding the electron beam through hole 28c on the surface on the side of the anode target and the inner surface 75b of the electron beam through hole 28c, fine frost-shaped by sandblasting or the like. Irregularities are provided. In this case, the unevenness may be formed in the region 75a surrounding the electron beam through hole 28c and the entire inner surface of the electron beam through hole 28c, and the inner surface of the electron beam through hole 28c into which many recoil electrons are incident. It may be formed only in part.

According to this configuration, the recoil electron trap 28
Has a large surface area and the blackened film 74 is formed, so that the heat radiation efficiency of the recoil electron trap 28 is improved. Also, because frost-like irregularities are formed,
The number of secondary scattered electrons reflected from the recoil electron trap 28 toward the anode target 17 is reduced, and accordingly, the heating of the anode target 17 is suppressed, and at the same time, the generation of unnecessary X-rays is suppressed.

In the embodiments shown in FIGS. 1, 2, 5, and 6, the insulation between the anode and cathode parts and the vacuum envelope is electrically insulated, and the vacuum envelope and the recoil electron The trap can be set to a so-called neutral grounding structure in which the trap is grounded, a positive voltage is applied to the anode part, and a negative voltage is applied to the cathode. 1 to 6, the anode portion and the vacuum envelope are electrically connected, the anode portion, the vacuum envelope, and the recoil electron trap are grounded, and a negative voltage is applied to the cathode. A so-called anode grounding structure for applying the voltage may be set. In this case, the recoil electron trap is grounded in the same manner as the anode part, and most of the backscattered electrons scattered backward among the electrons colliding with the anode target are captured by the fixed target. As a result, heating of the anode target due to re-collision of the backscattered electrons with the anode target is prevented, unnecessary emission of out-of-focus X-rays is eliminated, and deterioration of the clarity of the X-ray image is prevented.

In each of the above embodiments, the inner surface of the electron beam through hole provided on the recoil electron trap and both surfaces continuous with the opening of the electron beam through hole, for example, at least a part of the inner surface of the electron beam through hole. Is formed of a material having high heat resistance, for example, one of niobium and niobium alloy, molybdenum, molybdenum alloy, tantalum, tantalum alloy, tungsten, tungsten alloy, rhenium, and rhenium alloy. The melting of the trap and the generation of harmful gas from the recoil electron trap can be prevented.

Also, the inner surface of the electron beam through hole provided in the recoil electron trap and the surface around the electron beam through hole,
For example, if at least a part of the inner surface of the electron beam through hole is coated with a material having an atomic number of 45 or less, secondary scattered electrons generated by the impact of recoil electrons can be reduced.

A structure in which a part of the recoil electron trap is formed of copper or a copper alloy, and iron or nickel or a material containing these as a main component is directly or indirectly bonded on the copper or the copper alloy. You can also With this configuration, the heat storage capacity of the recoil electron trap can be increased by the heat storage function of iron or nickel without increasing the weight of the recoil electron trap. These materials are used at a temperature that does not exceed the Curie point by 100 ° C. or more during operation so that an effective heat storage function having a large specific heat, such as iron or nickel, can be obtained.

[0066]

According to the present invention, it is possible to realize a rotary anode type X-ray tube device provided with a rotary anode type X-ray tube having a recoil electron trap capable of coping with high output and preventing an increase in the size of the device.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view for explaining an embodiment of the present invention.

FIG. 2 is a schematic sectional view for explaining another embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view for explaining another embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view for explaining another embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view for explaining another embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view for explaining another embodiment of the present invention.

FIG. 7 is a diagram for explaining another embodiment of the present invention.
It is the schematic sectional drawing which extracted and showed the part of the recoil electron trap.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Tube container 111b ... 1st opening 111c ... 2nd opening 12 ... Rotating anode type X-ray tube 13 ... Vacuum envelope 14 ... Cathode 17 ... Anode target 17a ... Target layer 19 ... Inner rotating body 20 ... Outer rotation Body 23 ... thrust ring 28 ... recoil electron trap 28 c ... hole for electron beam e ... electron beam

Claims (10)

[Claims] 1. A rotating anode type X-ray tube and a rotating anode type X-ray tube.
A rotating anode X-ray tube, comprising: a cathode disposed in a vacuum envelope; and an anode target for emitting X-rays by irradiation of an electron beam generated by the cathode. A rotating body that rotates integrally with the anode target,
A rotating anode type X-ray tube apparatus having a fixed body constituting a rotating mechanism rotatably supporting the anode target together with the rotating body, and a recoil electron trap disposed between the cathode and the anode target. A rotating anode X-ray tube device, wherein the recoil electron trap is mechanically connected to a part of the vacuum envelope and is formed solid. 2. A rotating anode type X-ray tube, and said rotating anode type X-ray tube.
A rotating anode X-ray tube, comprising: a cathode disposed in a vacuum envelope; and an anode target for emitting X-rays by irradiation of an electron beam generated by the cathode. A rotating body that rotates integrally with the anode target,
A rotating anode type X-ray tube apparatus having a fixed body constituting a rotating mechanism rotatably supporting the anode target together with the rotating body, and a recoil electron trap disposed between the cathode and the anode target. A rotating anode type X-ray tube apparatus, wherein the recoil electron trap forms a part of the vacuum envelope and is formed solid. 3. The rotary anode X-ray tube apparatus according to claim 1, wherein a cooling passage through which a cooling medium flows is formed in a part of the vacuum envelope to which the recoil electron trap is mechanically connected. 4. The recoil electron trap is at least partially formed of a first member made of copper or a copper alloy, and iron, nickel, or a second member containing these as a main component is directly formed on the first member. 4. The rotary anode X-ray tube apparatus according to claim 1, wherein the rotary anode type X-ray tube apparatus is indirectly joined. 5. The rotary anode X-ray tube apparatus according to claim 4, wherein the second member is used within a temperature range not exceeding a Curie point by 100 ° C. or more. 6. At least a part of the inner surface of the electron beam through hole provided in the recoil electron trap is made of niobium and a niobium alloy, molybdenum, a molybdenum alloy, a tantalum, a tantalum alloy, a tungsten, a tungsten alloy, a rhenium, a rhenium alloy. The rotary anode type X-ray tube device according to any one of claims 1 to 5, wherein the rotary anode type X-ray tube device is formed of a material containing one of the following. 7. The rotary anode X-ray tube apparatus according to claim 1, wherein a groove is formed in at least a part of a surface of the recoil electron trap located on the cathode side. 8. A blackening film is formed on at least a part of the surface of the recoil electron trap located on the cathode side.
A rotating anode type X-ray tube apparatus according to claim 1. 9. The method according to claim 1, wherein fine frost-like irregularities are formed on at least a part of the inner surface of the electron beam through-hole provided in the recoil electron trap. Rotating anode type X-ray tube device. 10. At least a part of the inner surface of the electron beam through hole provided in the recoil electron trap has an atomic number of 45.
The rotating anode type X-ray tube device according to any one of claims 1 to 9, wherein the device is coated with the following material.