A cathode front end high voltage sealing structure for an open X-ray tube

Abstract

The present invention belongs to the technical field of sealing devices for X-ray tubes, and in particular, relates to a cathode front end high-pressure sealing structure for an open X-ray tube, comprising: an on-axis sleeve (1), a collimating lens (3), a primary magnet (12) and a secondary magnet (13); the top end of the on-axis sleeve (1) is inserted into and fixed on a cathode shell (2), a truncated cone structure is extended outwardly along the radial direction of the on-axis sleeve (1), the collimating lens (3) is sleeved outside the on-axis sleeve (1), a circular groove is provided on the truncated cone structure, and a rubber sealing ring is provided in the circular groove; the primary magnet (12) is sleeved outside the on-axis sleeve (1); the secondary magnet (13) is sleeved outside the on-axis sleeve (1) and is located below the primary magnet (12); the bottom end of the on-axis sleeve (1) is inserted into and fixed on a target holder (11), a circular groove is provided on the outer circumferential surface of the bottom end of the on-axis sleeve (1), and a rubber sealing ring is provided on the circular groove.

Description

Technical Field

[0001] The present invention belongs to the technical field of sealing devices for X-ray tubes required for industrial detection, medical CT and other equipment, and in particular, relates to a cathode front end high-voltage sealing structure for an open X-ray tube. Background Art

[0002] An X-ray tube is an instrument that uses high-speed electrons emitted by a cathode to collide with a metal target (anode target) to generate X-rays. The cathode component has a cathode filament to emit electrons. The electrons emitted by the cathode filament collide with the anode target after being accelerated by a high voltage of thousands to hundreds of thousands of volts. After the high-energy electrons collide with the anode target, X-rays are generated and radiated outward. Usually, the cathode filament is surrounded by a metal grid cover with a hole at the front end. The voltage of the metal grid cover is slightly lower than the voltage of the electrons emitted by the cathode filament, which causes the electrons emitted by the cathode filament to be compressed and focused at the front end of the metal grid cover.

[0003] In order to extend the service life of the cathode filament of the X-ray tube and avoid the energy loss of the electrons emitted by the cathode filament before hitting the target, the X-ray tube must be in a high vacuum state. According to the different vacuum sealing methods, X-ray tubes can be divided into open X-ray tubes and closed X-ray tubes. Open X-ray tubes have greater advantages in performance than closed X-ray tubes, so they have been widely used in many scenarios. Since open X-ray tubes require frequent disassembly, replacement of filaments and targets, their vacuum sealing is very important.

[0004] Generally speaking, there are one or more magnetic focusing lenses in the optical path of an open X-ray tube. Each magnetic focusing lens includes: an upper pole shoe and a lower pole shoe. In addition, there are sometimes components such as an astigmatism remover and a collimating lens. In order to vacuum seal the above components, a vacuum sealing structure is generally added to the position where two components are connected at each opening of the optical path. However, the existing sealing structure has a complex structure and needs to be sealed in multiple places. When a leak occurs, it is difficult to detect the specific location of the leak. Summary of the invention

[0005] In order to solve the above defects in the prior art, the present invention proposes a cathode front end high-voltage sealing structure for an open X-ray tube, which is arranged between the cathode housing and the target holder, and comprises: an on-axis sleeve, a collimating lens, a primary magnet and a secondary magnet;

[0006] The top end of the shaft sleeve is inserted into and fixed on the cathode shell, a truncated cone structure is extended outwardly in the radial direction of the shaft sleeve near the top end of the shaft sleeve, a collimating lens is sleeved outside the shaft sleeve near the truncated cone structure, and a circular groove is opened on the truncated cone structure, and a rubber sealing ring is arranged in the circular groove;

[0007] The primary magnet is sleeved outside the sleeve on the shaft and is threadedly fixed to the cathode shell located above the primary magnet;

[0008] The secondary magnet is sleeved outside the sleeve on the shaft and is located below the primary magnet;

[0009] The bottom end of the sleeve on the shaft is inserted into and fixed on the target holder, and a circular groove is provided on the outer circumferential surface of the bottom end of the sleeve on the shaft, and a rubber sealing ring is provided thereon.

[0010] As one of the improvements of the above technical solution, the primary magnet comprises: a primary magnet housing, a first solenoid and a primary magnet base;

[0011] The primary magnet shell is sleeved outside the sleeve on the shaft and is threadedly fixed to the cathode shell located above the primary magnet shell; the primary magnet base is arranged below the primary magnet shell, and a first sleeve structure extends upward from the middle of the primary magnet base, and the middle part of the primary magnet base is hollow, and the first sleeve structure is sleeved outside the sleeve on the shaft; the first solenoid located in the primary magnet shell is sleeved outside the first sleeve structure.

[0012] As one of the improvements of the above technical solution, the top end of the first sleeve structure is a conical structure.

[0013] As one of the improvements of the above technical solution, the secondary magnet comprises: a secondary magnet base, a secondary magnet housing and a second spiral tube;

[0014] A circular groove is provided on one side of the middle of the secondary magnet base, and a second sleeve structure is extended outward on the other side. The secondary magnet housing is arranged below the secondary magnet base and is threadedly fixed to the secondary magnet base; the second solenoid located in the secondary magnet housing is sleeved outside the second sleeve structure.

[0015] As one of the improvements of the above technical solution, the top end of the second sleeve structure is a conical structure.

[0016] As one of the improvements of the above technical solution, the sleeve on the shaft is made of non-magnetic material.

[0017] The beneficial effects of the present invention compared with the prior art are:

[0018] The cathode front end high-pressure sealing structure for an open X-ray tube provided by the present invention has a simple structure, is easy to disassemble and install, has a good vacuum sealing effect, and can accurately detect the leakage position. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a cathode front end high-voltage sealing structure for an open X-ray tube according to the present invention;

[0020] Figure 2It is a structural schematic diagram of a cathode front end high-voltage sealing structure for an open X-ray tube of the present invention, which is arranged between a cathode wire housing and a target holder.

[0021] Reference numerals:

[0022] 1. Sleeve on the shaft 2. Cathode shell

[0023] 3. Collimating lens 4. Primary magnet housing

[0024] 5. First solenoid 6. Primary magnet base

[0025] 7. Secondary magnet base 8. Secondary magnet housing

[0026] 9. Second solenoid 10. Anode target

[0027] 11. Target holder 12. Primary magnet

[0028] 13. Secondary magnet DETAILED DESCRIPTION

[0029] The present invention will now be further described with reference to the accompanying drawings.

[0030] like Figure 1 and 2 As shown, the present invention provides a cathode front end high-pressure sealing structure for an open X-ray tube, which is arranged between a cathode housing 2 and a target holder 11, and comprises: an on-axis sleeve 1, a collimating lens 3, a primary magnet 12 and a secondary magnet 13;

[0031] The top end of the shaft sleeve 1 is inserted into and fixed on the cathode housing 2. A truncated cone structure is extended outwardly in the radial direction of the shaft sleeve 1 near the top end of the shaft sleeve 1. The collimating lens 3 is mounted outside the shaft sleeve 1 near the truncated cone structure, and a circular groove is provided on the truncated cone structure. A rubber sealing ring is provided in the circular groove to form a vacuum seal. The axial sealing method is adopted to form an effective vacuum seal for the vacuum cavity in the cathode housing 2. In other specific embodiments, a radial sealing method can also be adopted for vacuum sealing.

[0032] The primary magnet 12 is sleeved outside the shaft sleeve 1 and is threadedly fixed to the cathode housing 2 located above the primary magnet 12;

[0033] The secondary magnet 13 is sleeved outside the shaft sleeve 1 and is located below the primary magnet 12;

[0034] The bottom end of the shaft sleeve 1 is inserted into and fixed on the target holder 11. A circular groove is provided on the outer circumferential surface of the bottom end of the shaft sleeve 1, and a rubber sealing ring is provided thereon, so that a vacuum seal is formed at the fixed connection between the bottom end of the shaft sleeve 1 and the target holder 11. A radial sealing method is adopted so that the vacuum cavity in the target holder 11 forms an effective vacuum sealing space. In other specific embodiments, an axial sealing method can also be adopted for vacuum sealing.

[0035] like Figure 1 As shown, the primary magnet 12 includes: a primary magnet housing 4, a first solenoid 5 and a primary magnet base 6;

[0036] The primary magnet housing 4 is sleeved outside the sleeve 1 on the shaft and is threadedly fixed to the cathode housing 2 located above the primary magnet housing 4; the primary magnet base 6 is arranged below the primary magnet housing 4, and the middle part of the primary magnet base 6 extends a first sleeve structure upward, and the middle part is hollow, and the first sleeve structure is sleeved outside the sleeve 1 on the shaft; the first solenoid 5 located in the primary magnet housing 4 is sleeved outside the first sleeve structure.

[0037] like Figure 1 As shown, the top of the first sleeve structure is a conical structure, the purpose of which is to maximize the magnetic field strength generated in the longitudinal area between the tip of the first sleeve structure and the top of the primary magnet housing 4, thereby ensuring the highest focusing of the electron beam injected into the on-axis sleeve 1;

[0038] The secondary magnet 13 comprises: a secondary magnet base 7, a secondary magnet housing 8 and a second spiral tube 9;

[0039] A circular groove is provided on one side of the middle of the secondary magnet base 7, and a second sleeve structure is extended outward on the other side thereof. The secondary magnet housing 8 is arranged below the secondary magnet base 7 and is threadedly fixed to the secondary magnet base 7; the second solenoid 9 located in the secondary magnet housing 8 is sleeved outside the second sleeve structure.

[0040] like Figure 1 and 2 As shown, the top end of the second sleeve structure is a conical structure, the purpose of which is to maximize the magnetic field strength generated in the longitudinal area between the tip of the second sleeve structure and the bottom of the secondary magnet housing 8, thereby ensuring that the electron beam injected into the on-axis sleeve 1 can still maintain the highest focusing after passing through the primary magnet 12.

[0041] The on-axis sleeve 1 is made of non-magnetic material, preferably aluminum, to avoid interference with the magnetic field formed by the primary magnet and the secondary magnet. The on-axis sleeve 1 is hollow inside, which can form a path for the electron beam emitted by the X-ray tube to ensure that the electron beam hits the anode target 10 located in the target holder 11 from the cathode wire.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the embodiments, it should be understood by those skilled in the art that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention and should be included in the scope of the claims of the present invention.

Claims

1. A cathode front end high voltage sealing structure for an open X-ray tube, comprising: An on-axis sleeve (1), a collimating lens (3), a primary magnet (12) and a secondary magnet (13); characterized in that: The top end of the shaft sleeve (1) is inserted into and fixed on the cathode housing (2), a truncated cone structure is extended outwardly in the radial direction of the shaft sleeve (1) near the top end of the shaft sleeve (1), a collimating lens (3) is sleeved outside the shaft sleeve (1) near the truncated cone structure, and a circular groove is formed on the truncated cone structure, and a rubber sealing ring is provided in the circular groove; The primary magnet (12) is sleeved outside the shaft sleeve (1) and is threadedly fixed to the cathode housing (2) located above the primary magnet (12); The secondary magnet (13) is sleeved outside the shaft sleeve (1) and is located below the primary magnet (12); The bottom end of the shaft sleeve (1) is inserted into and fixed on the target holder (11). A circular groove is provided on the outer circumferential surface of the bottom end of the shaft sleeve (1) and a rubber sealing ring is provided thereon.

2. The cathode front end high-voltage sealing structure for an open X-ray tube according to claim 1, characterized in that: The primary magnet (12) comprises: a primary magnet housing (4), a first solenoid (5) and a primary magnet base (6); The primary magnet housing (4) is sleeved outside the sleeve (1) on the shaft and is threadedly fixed to the cathode housing (2) located above the primary magnet housing (4); the primary magnet base (6) is arranged below the primary magnet housing (4); a first sleeve structure extends upward from the middle of the primary magnet base (6); the middle of the primary magnet base (6) is hollow; the first sleeve structure is sleeved outside the sleeve (1) on the shaft; and the first solenoid (5) located in the primary magnet housing (4) is sleeved outside the first sleeve structure.

3. The cathode front end high-voltage sealing structure for an open X-ray tube according to claim 2, characterized in that: The top end of the first sleeve structure is a cone-shaped structure.

4. The cathode front end high-voltage sealing structure for an open X-ray tube according to claim 1, characterized in that: The secondary magnet (13) comprises: a secondary magnet base (7), a secondary magnet housing (8) and a second solenoid (9); A circular groove is provided on one side of the middle of the secondary magnet base (7), and a second sleeve structure is extended outwardly from the other side thereof; the secondary magnet housing (8) is arranged below the secondary magnet base (7) and is threadedly fixed to the secondary magnet base (7); and the second solenoid (9) located in the secondary magnet housing (8) is sleeved outside the second sleeve structure.

5. The cathode front end high-voltage sealing structure for an open X-ray tube according to claim 4, characterized in that: The top end of the second sleeve structure is a cone-shaped structure.

6. The cathode front end high-voltage sealing structure for an open X-ray tube according to claim 1, characterized in that: The on-shaft sleeve (1) is made of non-magnetic material.

Images