A cathode device with multiple cathodes and a multi-cathode array source X-ray tube

Abstract

The present invention relates to a ray tube, in particular to a multi-cathode cathode device and a multi-cathode array source X-ray tube. A multi-cathode cathode device comprises: a cathode cover plate, a plurality of cathode assemblies, a plurality of connecting core columns and a plurality of lead wires, wherein the cathode cover plate is in a fan-shaped ring shape, a plurality of cathode assemblies are fixed to the bottom of the cathode cover plate and arranged in an arc array along the cathode cover plate, a plurality of connecting core columns are fixed to the top of the cathode cover plate, the number of connecting core columns is less than the number of cathode assemblies, and the connecting core columns are electrically connected to no less than two cathode assemblies through lead wires. The multi-cathode arc array X-ray tube provided by the present invention has a small number of ceramic core columns, is convenient to weld, has a simple process, and is not prone to air leakage during welding.

Description

Technical Field

[0001] The present invention relates to a ray tube, in particular to a cathode device with multiple cathodes and a multiple cathode array source X-ray tube. Background Art

[0002] X-ray tubes are used to generate X-rays and play an important role in various fields such as medical diagnosis, safety inspection and non-destructive testing. The basic principle of X-ray tubes is that the hot electrons excited by the heating of the cathode filament hit the target disk under the action of the anode and cathode accelerating electric fields. 1% of the energy is converted into X-rays, and the remaining approximately 99% of the energy is converted into heat energy, which causes the temperature of the impacted part to rise rapidly. The rotating anode X-ray tube adopts the method of the anode bearing driving the anode target disk to rotate at high speed in the vacuum tube shell, thereby dispersing the heat to the entire target disk, and transferring it to the vacuum tube shell through thermal radiation, and then the heat is taken away by the coolant flowing through the tube shell.

[0003] The current CT (Computed Tomography) system widely uses a rotating scanning method, where the gantry drives the rotating anode X-ray CT tube to perform rotating scanning imaging. This method is limited by the gantry rotation speed, and the anode bearing of the X-ray CT tube works under high centrifugal force conditions, which makes the bearing easy to be damaged, and then causes the entire X-ray CT tube to fail.

[0004] Compared with traditional CT, static CT uses a multi-focus X-ray tube, which avoids the high-speed rotation of traditional CT through multi-source exposure switching and achieves faster tomographic imaging. The arc array inside the multi-focus X-ray tube is equipped with multiple cathode assemblies, which are welded to the top of the tube shell and have wiring sockets. Since each cathode assembly needs to be welded and a hole needs to be opened on the top of the tube shell, each cathode assembly needs to be fully welded to ensure sealing. Due to the large number and the small distance between cathode assemblies, it is difficult to weld the cathode assemblies, the process is complicated, the welding cost is high, and it is easy to cause leakage, and the rework rate is high. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a multi-cathode arc array X-ray tube with a small number of ceramic core columns, convenient welding, simple process, and no leakage during welding. The specific technical solution is as follows:

[0006] A cathode device with multiple cathodes comprises: a cathode cover plate, a plurality of cathode assemblies, a plurality of connecting core columns and a plurality of lead wires, wherein the plurality of cathode assemblies are fixed to the bottom of the cathode cover plate and arranged in an arc array, and the plurality of connecting core columns are fixed to the top of the cathode cover plate, the number of the connecting core columns is less than the number of the cathode assemblies, and the connecting core columns are electrically connected to at least two of the cathode assemblies through the lead wires.

[0007] By adopting the above technical solution, the cathode assembly and the connecting core column are connected by a lead wire, so that one connecting core column corresponds to no less than two cathode assemblies, thereby reducing the number of connecting core columns, thereby reducing the welding workload, and the distance between adjacent connecting core columns becomes larger, welding is easier, the welding process is simpler, and the probability of leakage is reduced.

[0008] Preferably, the connecting core column includes: a cathode kovable ring, which is fixed on the cathode cover plate; a cathode ceramic column, which is fixed in the cathode kovable ring; and a cathode core column, wherein a plurality of cathode core columns are provided and the cathode core column is fixed on the cathode ceramic column, and the cathode core column is connected to the lead wire and corresponds one-to-one with the lead wire.

[0009] By adopting the above technical solution, the cathode ceramic column is used to insulate the cathode core column from the cathode kovar ring, and the cathode kovar ring is welded to the cathode cover plate.

[0010] Preferably, the cathode assembly includes: a filament, one end of which is electrically connected to the connecting core column through a lead wire, and the other end is grounded through a cathode cover; a grid, which is electrically connected to the connecting core column through a lead wire; a cathode ceramic seat, which is fixed to the cathode cover through the cathode ceramic seat; and a grid cover, which is installed on the grid, and both the grid cover and the grid are waist-shaped or elliptical.

[0011] By adopting the above technical solution, the gate adopts a waist-shaped or elliptical shape, avoiding the disadvantage of the traditional circular gate structure being too large, so more cathodes can be arranged in a limited space.

[0012] Wherein, the filament is arranged in a spiral.

[0013] A multi-cathode array source X-ray tube comprises: a multi-cathode cathode device as described above; a tube shell, a side of which is provided with an emission window, the multi-cathode cathode device being fixed on the top of the tube shell; and an anode assembly, the anode assembly being fixed on the bottom of the tube shell and arranged opposite to the multi-cathode cathode device, the anode assembly emitting rays toward the emission window.

[0014] Preferably, the anode assembly comprises: a target plate, which is in a fan-shaped ring shape, is arranged opposite to the cathode assembly, and is inclined toward the emission window; a substrate, which is in a fan-shaped ring shape, and the target plate is fixed on the substrate; a cooling plate, which is fixed to the bottom of the substrate; a cooling pipe, which is fixed to both ends of the cooling plate; an anode bracket, which is fixed to the bottom of the cooling plate; an anode cover plate, which is in a fan-shaped ring shape, and the cooling pipe and the anode bracket are both fixed to the anode cover plate; and an anode high-voltage core column, which is fixed to the anode cover plate and is electrically connected to the substrate.

[0015] Preferably, the anode high-voltage core column includes: an anode pin, which is electrically connected to the substrate; an anode ceramic column, on which the anode pin is fixed; and an anode kovar ring, through which the anode ceramic column is fixed to the anode cover plate.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The multi-cathode arc array X-ray tube provided by the invention has a small number of ceramic core columns, is convenient to weld, has a simple process, and is not prone to gas leakage during welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of a cathode device with multiple cathodes;

[0019] Figure 2 is a top view of a cathode device with multiple cathodes;

[0020] Figure 3 yes Figure 2 A partial enlarged view of point I in the middle;

[0021] Figure 4 It is a schematic diagram of the structure of the connecting core column;

[0022] Figure 5 is a schematic diagram of the structure of the cathode assembly;

[0023] Figure 6 It is a schematic diagram of the structure of the cathode assembly behind the grid cover;

[0024] Figure 7 A schematic diagram of the structure of a multi-cathode array source X-ray tube;

[0025] Figure 8 It is a schematic diagram of the structure of a multi-cathode array source X-ray tube hidden behind the tube shell;

[0026] Fig. 9 It is a schematic diagram of the structure of a multi-cathode array source X-ray tube in an upward-looking direction;

[0027] Fig.10 It is a schematic diagram of a ring composed of multiple multi-cathode array source X-ray tubes. DETAILED DESCRIPTION

[0028] The present invention will be further described with reference to the accompanying drawings. Embodiment 1

[0029] like Figures 1 to 6 As shown, a multi-cathode cathode device includes: a cathode cover plate 1, a plurality of cathode assemblies 3, a plurality of connecting core columns 2 and a plurality of lead wires 8, the cathode cover plate 1 is a fan ring, a plurality of cathode assemblies 3 are fixed to the bottom of the cathode cover plate 1 and arranged in an arc array along the cathode cover plate 1, a plurality of connecting core columns 2 are fixed to the top of the cathode cover plate 1, the number of connecting core columns 2 is less than the number of cathode assemblies 3, and the connecting core columns 2 are electrically connected to no less than two cathode assemblies 3 through the lead wires 8.

[0030] The arc array refers to an arrangement with equal spacing along the same arc line, and the cathode assembly 3 is arranged in an arc line array at the center of the sector-shaped cathode cover plate 1.

[0031] The cathode assembly 3 and the connecting core column 2 are connected by the lead wire 8, so that one connecting core column 2 corresponds to no less than two cathode assemblies 3, thereby reducing the number of connecting core columns 2, and further reducing the welding workload. In addition, the distance between adjacent connecting core columns 2 becomes larger, welding is easier, the welding process is simpler, and the probability of gas leakage is reduced.

[0032] like Figure 4 As shown, the connecting stem 2 includes: a cathode kovar ring 23, a cathode ceramic column 22 and a cathode stem 21. The cathode stem 21 is fixed on the cathode kovar ring 23 through the cathode ceramic column 22. There are multiple cathode stems 21. Specifically, the number of cathode stems 21 is twice the number of cathode assemblies 3 connected thereto. The cathode stem 21 is connected to the cathode assembly 3 through a lead 8. The cathode ceramic column 22 is used to insulate the cathode stem 21 from the cathode kovar ring 23. The cathode kovar ring 23 is welded to the cathode cover plate 1.

[0033] like Figure 5 and Figure 6 As shown, the cathode assembly 3 includes: a filament 31, one end of the filament 31 is electrically connected to the connecting stem 2 through a lead 8, and the other end is grounded through a cathode cover 1, and the filament 31 is spirally arranged; a grid 32, the grid 32 is electrically connected to the connecting stem 2 through a lead 8; a cathode ceramic holder 35, the grid 32 is fixed on the cathode cover 1 through the cathode ceramic holder 35; a grid cover 33, the grid cover 33 is installed on the grid 32, and the grid cover 33 and the grid 32 are both waist-shaped or elliptical.

[0034] The gate 32 is waist-shaped or oval-shaped, which avoids the disadvantage of the traditional circular gate 32 structure being too large, so more cathodes can be arranged in a limited space.

[0035] Specifically, the cathode assembly 3 includes: a grid 32, a filament 31, a lead sleeve 34, a cathode ceramic seat 35, a cathode base 36 and a grid cover 33, wherein a focusing groove 321 is provided on the top of the grid 32, and the filament 31 is located in the focusing groove 321; the grid 32 is fixed to the cathode ceramic seat 35 through the lead sleeve 34, the cathode ceramic seat 35 is fixed to the cathode cover 1 through the cathode base 36, and the grid cover 33 is installed on the grid 32.

[0036] The grid cover 33 is electrically connected to the lead sleeve 34 and is led out as a grid lead-out terminal 322, but is insulated from the cathode base 36 through the cathode ceramic base 35. The filament 31 is insulated from the cathode, one end of the filament 31 is led out as a filament power supply terminal 311, and the other end is led out as a filament ground terminal 312, and the filament ground terminal 312 is also connected to the cathode base 36 and electrically connected.

[0037] The grid 32 adopts a waist-shaped structure, which saves space compared to the traditional circular grid 32 structure and does not affect the withstand voltage performance of adjacent cathodes. Hot cathode X-ray tubes usually use spiral tungsten wires, and the length of the spiral tungsten wire is significantly greater than the diameter of the spiral. The use of a circular grid 32 occupies a large space in the width direction. In the application of multi-focus arc array X-ray tubes, it is difficult to arrange multiple cathode structures; while the waist-shaped structure adopted in this embodiment saves space and can arrange more cathodes.

[0038] The cathode component is a multi-cathode structure, and each cathode structure includes a grid 32, a filament 31, and an insulating part. In order to realize the functions of heating the filament 31 and cutting off the grid 32, each cathode structure has three terminals: a grid terminal, a filament terminal, and a ground terminal. Its ground terminal is directly connected to the cathode cover 1, while the grid terminal and the filament terminal are led out through the lead 8. The grid terminals and filament terminals of several cathode assemblies are collected and connected to the connecting core column 2, and the connecting core column 2 is welded to the cathode cover 1 by argon arc welding or other welding methods. Compared with the method of leading the cathode cover 1 through a ceramic core column for each cathode structure, this method reduces the number of welding times and reduces the probability of welding gas leakage. Embodiment 2

[0039] like Figures 1 to 9 As shown, a multi-cathode array source X-ray tube includes: a multi-cathode cathode device, a tube shell 5 and an anode assembly 4; the tube shell 5 is a fan-shaped ring, and the inner circular surface of the tube shell 5 is provided with an emission window 51 for emitting rays, and a multi-cathode cathode device is fixed on the top of the tube shell 5; the anode assembly 4 is fixed on the bottom of the tube shell 5 and is arranged opposite to the multi-cathode cathode device, and the anode assembly 4 emits rays toward the emission window 51.

[0040] Specifically, Figure 8 As shown, the anode assembly 4 includes: a target plate 41, a substrate 42, a cooling plate 43, a cooling tube 44, an anode bracket 45 and an anode cover plate 7; the target plate 41 is fan-shaped, inclined to the emission window 51, and the target plate 41 is arranged opposite to the cathode assembly 3; the substrate 42 is fan-shaped, the top surface is inclined to the emission window 51, and the target plate 41 is fixed to the top surface of the substrate 42; the cooling plate 43 is hollow, and the cooling plate 43 is fixed to the bottom of the substrate 42; the cooling tube 44 is a ceramic tube, and the cooling tube 44 is fixed to both ends of the cooling plate 43; the anode bracket 45 is a ceramic bracket, and the anode bracket 45 is fixed to the bottom of the cooling plate 43, and a plurality of them are symmetrically arranged; the anode cover plate 7 is fan-shaped, and the cooling tube 44 and the anode bracket 45 are both fixed on the anode cover plate 7; the anode high-voltage core column 6 is fixed on the anode cover plate 7 and is electrically connected to the substrate 42.

[0041] like Figure 8 and Fig. 9 As shown, the anode high-voltage core column 6 includes: an anode pin 61, an anode ceramic column 62 and an anode kovar ring 63; the anode pin 61 is electrically connected to the substrate 42; the anode pin 61 is fixed on the anode ceramic column 62; the anode ceramic column 62 is fixed on the anode cover plate 7 through the anode kovar ring 63.

[0042] In the working state, the cathode assembly 3 is at the ground voltage, while the anode target plate 41 is at a positive high voltage, and the cathode filament 31 is heated to excite hot electrons. At this time, by adjusting the voltage of the grid 32, the electric field near the emission surface of the filament 31 can be changed to control the cathode emission current, thereby realizing multi-source exposure switching. Fig.10 The ring-shaped structure shown can realize a multi-focus X-ray source for static CT.

[0043] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the protection scope of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific implementations of the present invention without paying creative labor, and these methods will fall within the protection scope of the claims of the present invention.

Claims

1. A cathode device with multiple cathodes, characterized in that: include: A cathode cover plate (1), a plurality of cathode assemblies (3), a plurality of connecting core columns (2) and a plurality of lead wires (8), wherein the plurality of cathode assemblies (3) are fixed to the bottom of the cathode cover plate (1) and arranged in an arc-shaped array, and the plurality of connecting core columns (2) are fixed to the top of the cathode cover plate (1), the number of the connecting core columns (2) is less than the number of the cathode assemblies (3), and the connecting core columns (2) are electrically connected to at least two cathode assemblies (3) via the lead wires (8); The cathode assembly (3) comprises: A filament (31), one end of the filament (31) being electrically connected to the connecting stem (2) via a lead wire (8), and the other end of the filament (31) being grounded via a cathode cover plate (1); A grid electrode (32), the grid electrode (32) being electrically connected to the connecting core column (2) via a lead wire (8); a cathode ceramic seat (35), wherein the grid (32) is fixed on the cathode cover plate (1) via the cathode ceramic seat (35); and A grid cover (33), the grid cover (33) being mounted on the grid (32), the grid cover (33) and the grid (32) both being waist-shaped or elliptical; The connecting core column (2) comprises: A cathode kovar ring (23), wherein the cathode kovar ring (23) is fixed on the cathode cover plate (1); a cathode ceramic column (22), wherein the cathode ceramic column (22) is fixed in the cathode kovar ring (23); and A cathode core column (21), wherein a plurality of cathode core columns (21) are provided, and the cathode core columns (21) are fixed on the cathode ceramic column (22), and the cathode core columns (21) are connected to the lead wire (8) and correspond one-to-one with the lead wire (8).

2. A multi-cathode cathode device according to claim 1, characterized in that: The filament (31) is arranged in a spiral.

3. A multi-cathode array source X-ray tube, characterized in that: include: A multi-cathode cathode device as claimed in claim 1; A tube shell (5), wherein an emission window (51) is provided on a side of the tube shell (5), and the multi-cathode cathode device is fixed on the top of the tube shell (5); and An anode assembly (4), the anode assembly (4) being fixed to the bottom of the tube shell (5) and arranged opposite to the cathode device of the multi-cathode, the anode assembly (4) emitting radiation towards the emission window (51).

4. The multi-cathode array source X-ray tube according to claim 3, characterized in that: The anode assembly (4) comprises: a target disk (41), the target disk (41) being in the shape of a fan ring, the target disk (41) being arranged opposite to the cathode assembly (3) and being arranged inclined toward the emission window (51); A base body (42), the base body (42) being in a sector ring shape, and the target plate (41) being fixed on the base body (42); A cooling plate (43), the cooling plate (43) being fixed on the bottom of the base (42); Cooling pipes (44), the cooling pipes (44) being fixed at both ends of the cooling plate (43); an anode support (45), wherein the anode support (45) is fixed to the bottom of the cooling plate (43); an anode cover plate (7), the anode cover plate (7) being in the shape of a fan ring, the cooling tube (44) and the anode support (45) being fixed on the anode cover plate (7); and An anode high-voltage core column (6), wherein the anode high-voltage core column (6) is fixed on the anode cover plate (7) and is electrically connected to the substrate (42).

5. The multi-cathode array source X-ray tube according to claim 4, characterized in that: The anode high-voltage core column (6) comprises: an anode pin (61), the anode pin (61) being electrically connected to the substrate (42); an anode ceramic column (62), the anode pin (61) being fixed on the anode ceramic column (62); and An anode kovar ring (63), wherein the anode ceramic column (62) is fixed to the anode cover plate (7) via the anode kovar ring (63).

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