CN110676143B

CN110676143B - Cathode structure of X-ray tube

Info

Publication number: CN110676143B
Application number: CN201910875090.1A
Authority: CN
Inventors: 曹阳; 李保权; 牟欢
Original assignee: National Space Science Center of CAS
Current assignee: National Space Science Center of CAS
Priority date: 2019-09-17
Filing date: 2019-09-17
Publication date: 2022-01-25
Anticipated expiration: 2039-09-17
Also published as: CN110676143A

Abstract

The invention relates to the technical field of X-ray tube preparation, in particular to an X-ray tube cathode structure, which comprises: the device comprises a grid (1), a cathode filament base (2), a transition socket (3), a ceramic base (4), a Kovar steel base (5), an electrode column (6) and a cathode filament (7); the Kovar steel base (5) is of a circular ring structure, and the ceramic base (4) is arranged in an inner ring of the Kovar steel base (5) of the circular ring structure; a first circular groove (8) is arranged between the ceramic base (4) and the inner ring of the Kovar steel base (5) with a circular ring structure; the transition socket (3) is arranged on the ceramic base (4), a plurality of electrode columns (6) are arranged in the transition socket (3), and sequentially penetrate through the transition socket (3) and the ceramic base (4) to be fixedly connected; the cathode filament base (2) is placed on the transition socket (3) and wrapped in the grid (1); the cathode filament (7) is arranged on the cathode filament base (2) and is connected with the top of the grid (1).

Description

Cathode structure of X-ray tube

Technical Field

The invention belongs to the technical field of X-ray tube preparation required by equipment such as industrial detection and medical CT (computed tomography), and particularly relates to a cathode structure of an X-ray tube.

Background

An X-ray tube is an instrument that generates X-rays by striking a metal target surface with high-speed electrons emitted from a cathode. The cathode component is provided with a cathode filament for emitting electrons, and the electrons emitted by the cathode filament strike the anode target after being accelerated by thousands to hundreds of thousands of volts.

Usually, the cathode filament is surrounded by a metal grid cover with an opening at the front end, and the voltage of the grid cover is slightly lower than that of the cathode filament, so that electrons emitted by the cathode filament are forced to focus at the front end of the grid. In order to prolong the service life of the cathode filament of the X-ray tube, the inside of the X-ray tube is required to be in a high vacuum state. Therefore, the mounting of the X-ray tube must take into account the vacuum seal.

In addition, for safety reasons, X-ray tubes often employ an arrangement in which the housing and the anode target are grounded, the cathode filament is connected to a high negative voltage, and the cathode filament and the grid are connected to different voltages. Therefore, the conventional X-ray tube cannot ensure that power is supplied to the cathode filament and the grid in the cathode structure of the X-ray tube without discharging. However, the conventional cathode structure of the X-ray tube generally has the problems of complicated structure and time-consuming disassembly and replacement of parts.

Disclosure of Invention

The invention aims to solve the technical defects of the conventional X-ray tube, and provides a cathode structure of the X-ray tube, which has the advantages of simple structure, safety, reliability, easy disassembly and convenient part installation and replacement.

In order to achieve the above object, the present invention proposes an X-ray tube cathode structure comprising: the device comprises a grid, a cathode filament base, a transition socket, a ceramic base, a Kovar steel base, an electrode column and a cathode filament;

the Kovar steel base is of a circular ring structure, the ceramic base is arranged in an inner ring of the Kovar steel base of the circular ring structure, and the ceramic base and the Kovar steel base are fixed on the same horizontal plane in a welding mode; a first circular groove is formed between the ceramic base and the inner ring of the Kovar steel base of the circular ring structure; the transition socket is fixedly arranged on the ceramic base, a plurality of electrode columns are arranged in the transition socket, sequentially pass through the transition socket and the ceramic base, and the transition socket and the ceramic base are fixedly connected; the cathode filament base is placed on the transition socket and wrapped in the grid; the cathode filament is arranged on the cathode filament base and connected with the top of the grid, and the cathode filament and the grid are powered through a plurality of electrodes.

As one improvement of the technical scheme, the transition socket is made of a non-conductive material such as polytetrafluoroethylene or PEEK and used for fixing the grid.

As one improvement of the above technical solution, the transition socket is in a hollow cylinder structure, and two ends of the transition socket respectively extend outwards to form a first cylindrical protrusion and a second cylindrical protrusion, and the diameters of the first cylindrical protrusion and the second cylindrical protrusion are both smaller than the diameter of the hollow cylinder of the transition socket; the outer circumference of the hollow cylinder structure is provided with opposite rectangular openings, a rectangular through hole is formed between the opposite rectangular openings, a rectangular plate is arranged in the rectangular through hole, and a plurality of symmetrical round holes are formed in two sides of the rectangular plate and used for correspondingly inserting the electrode columns into the round holes.

As one improvement of the technical scheme, the ceramic base is of a cylindrical structure, a second circular groove is formed in the middle of the ceramic base, and a second cylindrical protrusion is inserted into the second circular groove and is fixed on the transition socket; the bottom of the ceramic base is provided with a plurality of tubular projections for vacuum sealing welding with the corresponding electrode columns.

As one improvement of the technical scheme, the ceramic base is fixed in an inner ring of the Kovar steel base of the circular ring structure.

As one improvement of the technical scheme, the cathode filament is used for emitting electrons.

As one improvement of the technical scheme, the transition socket, the ceramic base and the Kovar steel base are integrally processed by adopting PEEK non-conductive materials.

Compared with the prior art, the invention has the beneficial effects that:

the cathode structure of the X-ray tube provided by the invention has the advantages of simple structure, safety, reliability, easy disassembly and convenient part installation and replacement.

Drawings

FIG. 1 is a schematic structural view of a cathode structure of an X-ray tube according to the present invention;

FIG. 2 is a schematic diagram of a transition socket of the cathode structure of the X-ray tube of FIG. 1 in accordance with the present invention;

FIG. 3 is a schematic diagram of the ceramic socket of the cathode structure of the X-ray tube of FIG. 1 in accordance with the present invention;

fig. 4 is a schematic view of the base structure of the ceramic socket of the cathode structure of the X-ray tube of fig. 1 according to the present invention.

Reference numerals:

1. grid 2, cathode filament base

3. Transition socket 4 and ceramic base

5. Kovar steel base 6 and electrode column

7. Cathode filament 8 and first circular groove

9. Second circular groove 10, first cylindrical protrusion

11. Second cylindrical projection 12, rectangular plate

13. Round hole 14, rectangular opening

15. Tubular projection

Detailed Description

The invention will now be further described with reference to the accompanying drawings.

As shown in fig. 1, the present invention proposes an X-ray tube cathode structure, which includes: grid 1, negative pole silk base 2, transition socket 3, ceramic base 4, kovar steel base 5, electrode post 6, negative pole silk 7.

The Kovar steel base 5 is of a circular ring structure, the ceramic base 4 is arranged in an inner ring of the Kovar steel base 5 of the circular ring structure, and the ceramic base and the Kovar steel base are fixed on the same horizontal plane in a welding mode; a first circular groove 8 is arranged between the ceramic base 4 and the inner ring of the Kovar steel base 5 with a circular ring structure; the transition socket 3 is fixedly arranged on the

ceramic base

4, 4 electrode columns 6 are arranged in the transition socket 3, sequentially penetrate through the transition socket 3 and the ceramic base 4, and are used for being insulated with the shell of the X-ray tube and fixedly connecting the transition socket 3 with the ceramic base 4; the cathode filament base 2 is placed on the transition socket 3 and is wrapped in the grid 1; the cathode filament 7 is arranged on the cathode filament base 2, is connected with the top of the grid 1 and supplies power to the cathode filament 7 and the grid 1 through 4 electrode columns 6.

The transition socket 3 is made of a non-conductive material such as polytetrafluoroethylene or PEEK and used for fixing the grid 1.

As shown in fig. 2, the transition socket 3 is a hollow cylinder structure, two ends of the transition socket 3 respectively extend outward to form a first cylindrical protrusion 10 and a second cylindrical protrusion 11, and the diameters of the first cylindrical protrusion 10 and the second cylindrical protrusion 11 are both smaller than the diameter of the hollow cylinder of the transition socket 3; the outer circumference of the hollow cylinder structure is provided with opposite rectangular openings 14, a rectangular through hole is arranged between the opposite rectangular openings 14, a rectangular plate 12 is arranged in the rectangular through hole, and a plurality of symmetrical round holes 13 are arranged on two sides of the rectangular plate 12 and used for correspondingly inserting the electrode columns 6 into the round holes 13. Wherein the circular hole 13 is provided on the hollow cylindrical structure.

As shown in fig. 3, the ceramic base 4 is a cylindrical structure, and a second circular groove 9 is formed in the middle of the ceramic base, and a second cylindrical protrusion 11 is inserted into the second circular groove 9 for being fixed to the transition socket 3; as shown in fig. 4, the bottom of the ceramic base 4 is provided with 4 tubular projections 15 for vacuum seal welding with the corresponding electrode posts 6.

The ceramic base 4 is fixed in an inner ring of a Kovar steel base 5 of a circular ring structure.

The cathode filament 7 is used for emitting electrons.

When the cathode structure is installed, firstly, the cathode filament base 2 is installed and fixed on the transition socket 1, and the fixation between the cathode filament base 2 and the transition socket 3 can be realized in various ways, for example, as shown in fig. 1, mainly through the stress of the polytetrafluoroethylene material. The grid 1 is fixed on the transition socket 3, the cathode wire base 2 is wrapped in the grid 1, and the matching between the grid 1 and the transition socket 3 depends on the stress of the matching part. The ceramic base 4 is fixed on the Kovar steel base 5 by welding, and a cathode is covered on the Kovar steel base 5 to seal the whole cathode structure, so as to ensure the firmness and reliability of vacuum sealing. The welding between the ceramic base 4 and the kovar steel base 5 can adopt a plurality of welding modes such as flat sealing, sleeve sealing and the like, wherein in the embodiment, the flat sealing welding mode is adopted, and in order to avoid the damage of devices caused by the inconsistency of the thermal expansion coefficients of ceramic and kovar steel at the welding part, the thickness of the kovar steel at the welding part is about 0.5 mm. Next, the transition socket 3, the ceramic base 4 and the electrode column 6 are installed and fixed as shown in fig. 1, wherein the transition socket 3 is fixed by a nut screwed on the electrode column, and the electrode column 6 and the ceramic base 4 need to be vacuum-sealed, and the sealing between them can be realized by welding or using a vacuum sealant. One end of each electrode column 6 is connected with a power supply, and the other end of each electrode column is connected with the grid 1 or the cathode wire 7 through a lead.

The cathode filament 7 is easy to damage and often needs to be replaced, the X-ray tube cathode structure provided by the invention is also very convenient for replacing the cathode filament, after the cathode filament is damaged, the grid 1 is disassembled, the original cathode filament base 2 is taken down, a new cathode filament is installed again, and the parts do not need to be disassembled.

In other specific embodiments, the transition socket 3, the ceramic base 4 and the kovar steel base 5 are integrally processed by using a high-strength non-conductive material of PEEK, and the 3 independent parts are processed into 1 integral part, so that the structural performance of the integral part is unchanged.

The cathode of the X-ray tube provided by the invention has the advantages of simple structure, safety, reliability, easy disassembly and convenient part installation and replacement.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. An X-ray tube cathode structure, comprising: the device comprises a grid (1), a cathode filament base (2), a transition socket (3), a ceramic base (4), a Kovar steel base (5), an electrode column (6) and a cathode filament (7);

the Kovar steel base (5) is of a circular ring structure, the ceramic base (4) is arranged in an inner ring of the Kovar steel base (5) of the circular ring structure, and the ceramic base and the Kovar steel base are fixed on the same horizontal plane in a welding mode; a first circular groove (8) is arranged between the ceramic base (4) and the inner ring of the Kovar steel base (5) with a circular ring structure; the transition socket (3) is fixedly arranged on the ceramic base (4), a plurality of electrode columns (6) are arranged in the transition socket (3), sequentially penetrate through the transition socket (3) and the ceramic base (4), and the transition socket (3) is fixedly connected with the ceramic base (4); the cathode filament base (2) is placed on the transition socket (3) and wrapped in the grid (1); the cathode filament (7) is arranged on the cathode filament base (2), is connected with the top of the grid (1), and supplies power to the cathode filament (7) and the grid (1) through a plurality of electrode columns (6);

the transition socket (3) is of a hollow cylinder structure, two ends of the transition socket (3) respectively extend outwards to form a first cylindrical bulge (10) and a second cylindrical bulge (11), and the diameters of the first cylindrical bulge (10) and the second cylindrical bulge (11) are smaller than the diameter of the hollow cylinder of the transition socket (3); the outer circumference of the hollow cylinder structure is provided with opposite rectangular openings (14), a rectangular through hole is arranged between the opposite rectangular openings (14), a rectangular plate (12) is arranged in the rectangular through hole, and a plurality of symmetrical round holes (13) are arranged on two sides of the rectangular plate (12).

2. X-ray tube cathode structure according to claim 1, characterized in that the transition socket (3) is made of a non-conductive material of polytetrafluoroethylene or PEEK.

3. X-ray tube cathode structure according to claim 1, characterized in that the ceramic mount (4) is of cylindrical configuration and has a second circular recess (9) opened in its middle, into which second circular recess (9) a second cylindrical projection (11) is inserted for fixing to the transition socket (3); the bottom of the ceramic base (4) is provided with a plurality of tubular projections (15) which are used for carrying out vacuum seal welding with the corresponding electrode columns (6).

4. X-ray tube cathode structure according to claim 1, characterized in that the ceramic mount (4) is fixed within the inner ring of a circular ring structure's kovar steel mount (5).

5. X-ray tube cathode structure according to claim 1, characterized in that the cathode filament (7) is adapted to emit electrons.

6. X-ray tube cathode structure according to claim 1, characterized in that the transition socket (3), the ceramic mount (4) and the kovar base (5) are integrally machined from a non-conductive material of PEEK.