X-ray tube

Abstract

The utility model belongs to the technical field of X-ray generation, and particularly relates to an X-ray tube. According to the X-ray tube, the first blackening getter film layer is prepared and formed in the tube shell, and the second blackening getter film layer is prepared and formed on the rotor of the anode assembly, so that the absorptivity of secondary electrons generated by invalid bombardment of an anode target material in the X-ray tube is improved, help is provided for guaranteeing the vacuum degree and the vacuum stability of a bulb tube of the X-ray tube, and the service life of the X-ray tube is prolonged. And the cathode structure can be simplified, so that the miniaturization of the X-ray tube structure can be realized. The utility model provides an X-ray tube. The X-ray tube comprises a cathode assembly, a tube shell and an anode assembly, the cathode assembly is composed of a filament loop and a cathode supporting assembly. A first blackening getter film layer prepared by using a high-energy plating process is arranged in the tube shell; the anode assembly comprises a rotor, and the outer surface of the rotor is provided with a second blackening getter film layer prepared and formed through the high-energy plating technology.

Description

Technical Field

[0001] The utility model belongs to the technical field of X-ray generation, and in particular relates to an X-ray tube. Background Art

[0002] As a vacuum diode device working in a high voltage environment, the X-ray tube specifically includes two electrodes: a cathode for emitting electrons and an anode (target) for receiving electron bombardment. During operation, the cathode filament of the X-ray tube releases a large number of free electrons; these electrons are accelerated by the cathode / anode electric field and collide with the anode target surface. Among them, about 60% of the free electrons will further interact with the anode target. And of this part, only about 1% of the energy can be converted into X-rays, and the remaining 99% of the energy will be converted into heat.

[0003] After further research, it was found that the main factors affecting the service life of X-ray tubes are as follows: 1) Free electrons that do not participate in bombarding the anode target will hit the wall of the X-ray tube; this will cause the residual gas molecules on the wall to be released back into the vacuum inside the X-ray tube, causing the vacuum inside the X-ray tube to decrease; on the other hand, the accumulation of free electrons on the wall of the X-ray tube will also cause the potential distribution of the wall to be uneven, thereby disturbing the normal working electric field of the X-ray tube and affecting its electrical stability. 2) If the heat generated by the collision of free electrons cannot be dissipated in time, it will accumulate and generate high heat; and the high heat will further damage the anode and cause the X-ray tube to fail.

[0004] Therefore, in order to solve the above technical problems, technicians usually choose to use the following technical means: one is to encapsulate the evaporative air-absorbing film layer or degassing agent to the cathode end of the X-ray tube during the production process of the X-ray tube. After the exhaust of the X-ray tube is completed, the air-absorbing film layer or degassing agent is evaporated to the cathode tube wall or cathode material by power supply or induction heating, so as to obtain a larger air-absorbing area. The evaporated air-absorbing film layer or degassing agent film layer can effectively absorb the free gas released from the tube wall or other internal materials, thereby ensuring the stability of the vacuum degree in the tube. However, the air-absorbing film layer or degassing agent film layer prepared by this technical means has a weak bonding force with the substrate. Under the action of the high-voltage electric field, the air-absorbing film layer or degassing agent film layer will gradually fall off from the substrate, thereby forming powder particles and being free in the X-ray tube. These particles will seriously affect the pressure resistance of the X-ray tube, and eventually cause the X-ray tube to lose its normal working ability. In addition, the design of the evaporative degassing agent also requires a separate activation circuit to be designed at the cathode end, and a large surface area needs to be reserved to ensure that the degassing agent can be effectively evaporated during the process. This inevitably complicates the cathode design structure, increases production costs, and reduces the flexibility of X-ray tube design.

[0005] The second is to use a block degassing agent and assemble it in the cathode assembly of the X-ray tube. After the X-ray tube is exhausted, the block degassing agent is powered on to activate it so that it has the ability to absorb air. Generally speaking, in order to obtain higher air absorption performance, the block degassing agent must be prepared into a loose and porous structure to increase the surface area and thus obtain stronger air absorption performance. However, in the specific implementation process, the inventors found that slight scratches, vibrations, and high-voltage electric fields can cause the metal particles in the block degassing agent to fall off; and powdering is an inevitable phenomenon in the preparation and use of the degassing agent. In addition, in order to activate the block degassing agent, technicians also need to design and reserve additional placement space and activation circuits, which will inevitably complicate the structure of the X-ray tube.

[0006] Based on the above situation, it is urgent for those skilled in the art to provide a new X-ray tube structure design so as to further flexibly and miniaturize the X-ray tube design on the basis of overcoming the above-mentioned defects of the existing X-ray tubes. Utility Model Content

[0007] The utility model provides an X-ray tube. The X-ray tube forms a first blackened getter film layer in a tube shell and a second blackened getter film layer on a rotor of an anode assembly, thereby improving the absorption rate of secondary electrons ineffectively generated by bombarding an anode target in the X-ray tube, which not only helps to ensure the vacuum degree and vacuum stability of the X-ray tube, but also helps to simplify the cathode structure so as to realize the miniaturization of the X-ray tube structure.

[0008] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0009] An X-ray tube comprises: a cathode assembly (110), a tube shell (200) and an anode assembly (300);

[0010] The cathode assembly (110) is composed of a filament loop (100) and a cathode support assembly (120);

[0011] A first blackened getter film layer (700) formed by using a high-energy plating process is arranged in the tube shell (200);

[0012] The anode assembly (300) comprises a rotor (310), and a second blackened getter film layer (710) prepared by a high-energy plating process is provided on the outer surface of the rotor (310).

[0013] Preferably, the degassing side surfaces of the first blackened getter film layer (700) and the second blackened getter film layer (710) are further provided with a concave-convex micro-nano structure (720).

[0014] Preferably, the first blackened getter film layer (700) and the second blackened getter film layer (710) are formed by magnetron sputtering.

[0015] Preferably, the first blackened getter film layer (700) and the second blackened getter film layer (710) are both made of titanium-based getter materials;

[0016] The first blackened getter film layer (700) and the second blackened getter film layer (710) prepared and formed have a film thickness of 1 to 3 micrometers and an adhesion of 4 to 6 N / cm.

[0017] Preferably, the activation temperature of the first blackened getter film layer (700) and the second blackened getter film layer (710) is 450 to 600 degrees Celsius, and the activation time is 20 to 30 minutes.

[0018] The utility model provides an X-ray tube, which includes a cathode assembly, a tube shell and an anode assembly. The cathode assembly is composed of a filament loop and a cathode support assembly; a first blackened getter film layer prepared by a high-energy plating process is arranged in the tube shell; the anode assembly includes a rotor, and a second blackened getter film layer prepared by a high-energy plating process is arranged on the outer surface of the rotor. The X-ray tube with the above structural features introduces a blackened getter film layer with a degassing function through a new tube design method. Compared with the prior art, the X-ray tube provided by the utility model has better tube vacuum and heat dissipation performance, and simplifies the cathode structure, which helps the miniaturization design of the X-ray tube structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation on the present invention. In the following drawings:

[0020] Figure 1 A schematic diagram of the structure of the X-ray tube provided by the utility model;

[0021] Figure 2 Schematic diagram of the blackened getter film layer and the micro-nano structure absorbing secondary electrons;

[0022] Figure 3 It is a data diagram of the first round of test comparison of the exhaust rate test between the X-ray tube using the traditional solid getter and the X-ray tube provided by the utility model;

[0023] Figure 4 It is a data diagram of the second round of test comparison of the exhaust rate test between the X-ray tube using the traditional solid getter and the X-ray tube provided by the utility model;

[0024] Reference numerals:

[0025] 100: cathode connection; 110: cathode assembly; 120: cathode head; 200: tube shell; 210: ray window; 300: anode assembly; 310: rotor; 320: anode target; 400: high-energy electrons; 500: X-rays; 600: vacuum; 700: first blackened getter film layer; 710: second blackened getter film layer; 720: micro-nano structure; 800: vacuum free gas; 820: secondary electrons. DETAILED DESCRIPTION

[0026] The utility model provides an X-ray tube. The X-ray tube forms a first blackened getter film layer in a tube shell and a second blackened getter film layer on a rotor of an anode assembly, thereby improving the absorption rate of secondary electrons ineffectively generated by bombarding an anode target in the X-ray tube, which not only helps to ensure the vacuum degree and vacuum stability of the X-ray tube, but also helps to simplify the cathode structure so as to realize the miniaturization of the X-ray tube structure.

[0027] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0028] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, in the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. Embodiment 1

[0029] The utility model provides an X-ray tube, such as Figure 1 As shown, it specifically includes: a cathode assembly (110), a tube shell (200) and an anode assembly (300).

[0030] The cathode assembly (110) is composed of a filament loop (100) and a cathode support assembly (120); a first blackened getter film layer (700) prepared using a high-energy plating process is provided in the tube shell (200); and the anode assembly (300) includes a rotor (310), and a second blackened getter film layer (710) prepared using a high-energy plating process is provided on the outer surface of the rotor (310).

[0031] It is worth noting that, since the utility model is provided with a first blackened getter film layer (700) on the tube shell (200), and a second blackened getter film layer (710) on the rotor (310) of the anode assembly (300), and the first blackened getter film layer (700) and the second blackened getter film layer (710) are used to achieve degassing of the X-ray tube, in this way, the X-ray tube provided by the utility model no longer needs to be provided with an additional degassing agent storage space and an activation circuit, thereby effectively ensuring the miniaturization of the X-ray tube design structure.

[0032] Further, as a more preferred embodiment of the present invention, Figure 2 As shown, a concave-convex micro-nano structure (720) is also provided on the degassing side surface of the first blackened getter film layer (700) and the second blackened getter film layer (710). The micro-nano structure (720) can effectively absorb secondary electrons (900). It should be supplemented that, by absorbing secondary electrons, the X-ray tube provided by the utility model can effectively improve its heat dissipation performance and the electrical stability of the tube, and reduce the probability of ignition. Embodiment 2

[0033] On the basis of Example 1, the applicant further describes the first blackened getter film layer (700) and the second blackened getter film layer (710) recorded in Example 1 in further detail, and the details can be referred to as follows:

[0034] The first blackened getter film layer (700) provided on the tube shell (200) and the second blackened getter film layer (710) provided on the rotor (310) of the anode assembly (300) can achieve effective degassing of the X-ray tube, thereby further optimizing the X-ray tube's requirements for degassing agent storage space and activation circuit. The first blackened getter film layer and the second blackened getter film layer can be further prepared and formed by referring to the following method:

[0035] As a more preferred embodiment of the utility model, the first blackened getter film layer (700) and the second blackened getter film layer (710) are prepared by magnetron sputtering, and the first blackened getter film layer (700) and the second blackened getter film layer (710) are both prepared by titanium-based getter material. The prepared first blackened getter film layer (700) and the second blackened getter film layer (710) have a film thickness of 1 to 3 microns and a film adhesion of 4 to 6 N / cm. It is worth noting that the preparation by magnetron sputtering can effectively improve the film adhesion of the first blackened getter film layer and the second blackened getter film layer, reduce film shedding and the generation of traditional getter particles.

[0036] Then, as a preferred embodiment of the utility model, the activation temperature of the first blackened getter film layer (700) and the second blackened getter film layer (710) is 450 to 600 degrees Celsius, and the activation time is 20 to 30 minutes. After the X-ray tube is exhausted, the blackened getter film layer can be activated using the existing common process, thereby eliminating the need to arrange a separate activation circuit for the getter.

[0037] We take the second blackened getter film layer (710) disposed on the rotor (310) in the anode assembly (300) as an example for explanation: technicians may preferably use magnetron sputtering to prepare the second blackened getter. During preparation, titanium-based getter material is first sputtered and Ar is selected as the reaction gas. The vacuum degree of the target background in the film coating process can be referenced to 7.0*10 -3 Pa. The rotor is fixed on the rotating bracket, the speed is selected to be rpm / 22″, the starting pressure of the magnetron sputtering operation is 0.1-0.20Pa, the target control current is 5-7A, and the voltage is 400V-500V. Through the sputtering process, the second blackened getter film layer exhibits a surface absorption rate greater than 0.9, thereby ensuring that the blackened getter film layer has a higher heat dissipation performance.

[0038] After completing the above-mentioned blackened getter film preparation process, the X-ray tube structure is further assembled and installed, and the exhaust rate is compared with the existing X-ray tube. The test plan can be referred to as follows:

[0039] First, the test equipment is two molecular pump exhaust devices with the same configuration, and two X-ray tubes of the same model are prepared. One of the X-ray tubes uses a traditional solid getter, and the other is an X-ray tube provided by the utility model (a blackened getter film layer is prepared on the rotor and the inner wall of the shell). The cathode end of each X-ray tube is sealed with a vacuum gauge that can measure the vacuum inside the tube. The test is divided into the following two steps. The first step is to assemble the two X-ray tubes to two exhaust devices respectively, apply the same exhaust process to the two X-ray tubes, and record the vacuum degree in the tube during the whole process; the second step is to remove the two tubes from the exhaust device. After the X-ray tubes are exposed to the atmosphere for one day, the workstation is changed to conduct the exhaust experiment again, and the change of the vacuum degree in the X-ray tube is recorded during this process.

[0040] The results of the two experiments can be found in Figure 3 , Figure 4 As shown. From the test results, it can be found that the speed and amplitude of the vacuum degree reduction of the X-ray tube provided by the utility model during the exhaust process are much better than those of the existing X-ray tubes, which is mainly due to the rapid air suction effect brought by the large area of ​​the blackened degassing agent film layer. Therefore, it is proved that the X-ray tube provided by the utility model can complete the exhaust process faster, save process time, and reduce manufacturing costs because it is equipped with a blackened degassing agent film layer.

[0041] The utility model provides an X-ray tube, which includes a cathode assembly, a tube shell and an anode assembly. The cathode assembly is composed of a filament loop and a cathode support assembly; a first blackened getter film layer prepared by a high-energy plating process is arranged in the tube shell; the anode assembly includes a rotor, and a second blackened getter film layer prepared by a high-energy plating process is arranged on the outer surface of the rotor. The X-ray tube with the above structural features introduces a blackened getter film layer with a degassing function through a new tube design method. Compared with the prior art, the X-ray tube provided by the utility model has better tube vacuum and heat dissipation performance, and simplifies the cathode structure, which helps the miniaturization design of the X-ray tube structure.

[0042] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. An X-ray tube, characterized in that: It comprises: a cathode assembly (110), a tube shell (200) and an anode assembly (300); The cathode assembly (110) is composed of a filament loop (100) and a cathode support assembly (120); A first blackened getter film layer (700) formed by using a high-energy plating process is arranged in the tube shell (200); The anode assembly (300) comprises a rotor (310), and a second blackened getter film layer (710) prepared by a high-energy plating process is provided on the outer surface of the rotor (310).

2. An X-ray tube according to claim 1, characterized in that: The degassing side surfaces of the first blackened getter film layer (700) and the second blackened getter film layer (710) are also provided with a concavo-convex micro-nano structure (720).

3. An X-ray tube according to claim 2, characterized in that: The first blackened getter film layer (700) and the second blackened getter film layer (710) are prepared by magnetron sputtering.

4. An X-ray tube according to claim 2, characterized in that: The first blackened getter film layer (700) and the second blackened getter film layer (710) are both prepared by using titanium-based getter materials; The first blackened getter film layer (700) and the second blackened getter film layer (710) prepared and formed have a film thickness of 1 to 3 micrometers and an adhesion of 4 to 6 N / cm.

5. An X-ray tube according to claim 2, characterized in that: The activation temperature of the first blackened getter film layer (700) and the second blackened getter film layer (710) is 450 to 600 degrees Celsius, and the activation time is 20 to 30 minutes.

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