Longitudinally-split modulated graphene quasi-three-dimensional soaking high-thermal-conductivity X-ray target and ray tube

Abstract

The utility model discloses a longitudinally-split modulated graphene quasi-three-dimensional soaking high-thermal-conductivity X-ray target and a ray tube. The X-ray target comprises a heat dissipation base body, a target arranged on the surface of the heat dissipation base body and a two-dimensional graphene vapor chamber used for in-plane two-dimensional heat conduction, the two-dimensional graphene vapor chamber is arranged on the surface of the heat dissipation base body and located below the target, and a longitudinal heat conductor which extends in the longitudinal direction and is used for longitudinal heat conduction is arranged in the two-dimensional graphene vapor chamber. By adopting the longitudinally-split modulated graphene quasi-three-dimensional soaking high-thermal-conductivity X-ray target as an X-ray target substrate, longitudinal high thermal conductivity can be realized, and the heat dissipation capability of the target substrate is improved from two-dimensional soaking to quasi-three-dimensional soaking.

Description

Technical Field

[0001] The utility model belongs to the field of X-ray applications, and particularly relates to a heat conduction technology for an X-ray tube target. Background Art

[0002] X-ray sources have a wide range of applications in the fields of industrial inspection, scientific instruments, medical imaging and treatment, etc. For example, Figure 1 The X-ray source shown mainly includes a cathode head 1, an anode head 3. Both the cathode head 1 and the anode head 3 are installed through a tube shell 5. A cathode 2 is arranged in the cathode head 1, and a target 4 is arranged in the anode head 3. The cathode 2 is opposite to the target 4. The electron beam 7 emitted from the cathode head 1 bombards the target 4 material to generate X-rays 8. The vast majority (~99%) of the electron beam power is finally deposited in the target material (usually refractory metals such as tungsten) in the form of heat. If the electron beam power is too large, the target will be melted. Therefore, the heat management of the X-ray conversion target belongs to one of the core technologies of the ray source.

[0003] Due to the low thermal conductivity of refractory metals, in order to solve the heat dissipation problem, it is usually necessary to combine a material with good thermal conductivity with the target (such as Figure 1 As shown in the figure, a copper heat sink 6 is used), to promote the conduction of heat away and avoid the temperature of the target being too high. On this basis, convective heat dissipation can be further achieved by using circulating insulating oil, or super-evaporative heat dissipation can be carried out by using cooling water (such as Figure 1 The cooling liquid 9 shown in the figure).

[0004] As Figure 2 shown, X-ray sources generally use casting or welding methods to use copper (or copper alloy) materials with good thermal conductivity as the heat dissipation matrix 6 of the tungsten target. The side close to the target 4 is the hot end 13, and the side far from the target is the cold end 14. The heat is conducted to the outer shell through the target material and the heat dissipation matrix, and is cooled and taken away by air cooling or liquid (as shown by the arrow in Figure 2 ). For a reflective X-ray source, the target usually has a reflection angle. While achieving a small focal spot, the electron beam power density can be reduced by one order of magnitude.

[0005] For a fixed target X-ray source, when the power is further increased, the temperature of the target is too high and the thermal stress increases, which will cause deformation, cracking of the target layer or melting of the copper heat sink; in addition, due to the too high metal vapor pressure, the vacuum degree in the tube decreases and the surface of the insulating component is contaminated, resulting in insulation failure under high voltage.

[0006] In the micro-focus X-ray tube widely used in semiconductor and new energy battery detection, the total electron beam power is not high, only 5 - 80W, but the focal spot is very small, only 5 - 100um. Therefore, the X-ray tube power / focal spot square ratio is as high as 0.2W / um 2 , much higher than 0.00125W / um of high-power ray tubes2 (The electron beam power is 5 kW and the focal spot size is 2 mm). For a scenario where the total power is not large, but the local power density is very high, to significantly improve the power / focal spot square ratio of a fixed micro-focus X-ray tube and improve the imaging efficiency while enhancing the imaging accuracy, there is an urgent need for a heat dissipation matrix of an X-ray target with good thermal conductivity to rapidly reduce the local power density at the electron beam bombardment position.

[0007] In the fields of semiconductors and new energy batteries, heat pipe and graphene heat dissipation technologies have been widely applied. Among them, the two-dimensional vapor chamber is a highly thermally conductive structure. As Figure 3 shown, its principle is to rapidly disperse local heat to a large area by leveraging the two-dimensional high thermal conductivity (5000 W / (m·K)) of woven graphene, thereby achieving cooling of high power density deposition positions. Therefore, there are also studies on applying it to the heat conduction of X-ray tube targets. However, the existing technology simply uses a layer of two-dimensional graphene vapor chamber 10 arranged below the target, attempting to reduce the temperature at the center of the target through two-dimensional heat conduction. This technology has the following defects:

[0008] Although the thermal conductivity of the graphene heat dissipation layer in the plane is very high (much greater than 400 W / (m·K) of copper, as Figure 3 the horizontal arrow in the figure shows two-dimensional heat conduction 12 in the plane, the interlayer thermal conductivity of graphene is only 16, as Figure 3 the vertical arrow in the figure shows longitudinal heat conduction 11, which is much less than 400 of copper. Therefore, its heat conduction has very obvious anisotropic characteristics, and its actual heat conduction ability is very limited. At the same time, the heat conduction between graphene and copper is not good, and there is an obvious interface. To promote heat conduction, first, the surface of graphene needs to be metallized, as Figure 3 the hot end 13 in the figure uses a metallized layer. And the effective bonding thickness between the metallized layer and graphene is only a few nanometers (a thicker metallized layer does not have two-dimensional heat conduction performance). Therefore, as shown in the figure, only the woven graphene on one side close to the metallized layer can conduct heat well, and at positions far from the heat source, due to the very small longitudinal thermal conductivity, its two-dimensional high thermal conductivity contributes little to actual heat dissipation. Summary of the Invention

[0009] In view of the above problems existing in the prior art, the present invention provides a longitudinally slit-modulated graphene quasi-three-dimensional heat-conducting and highly thermally conductive X-ray target and X-ray tube.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] Longitudinally split modulated graphene quasi-three-dimensional heat dissipation high thermal conductivity X-ray target, including a heat dissipation substrate, a target disposed on the surface of the heat dissipation substrate, and a two-dimensional graphene heat dissipation plate for in-plane two-dimensional heat conduction. The two-dimensional graphene heat dissipation plate is disposed on the surface of the heat dissipation substrate and is located below the target. A longitudinally extending longitudinally heat conducting body for longitudinal heat conduction is provided in the two-dimensional graphene heat dissipation plate.

[0012] Furthermore, a metallization layer is provided on the surface of the two-dimensional graphene heat dissipation plate, and the metallization layer is located below the target.

[0013] Furthermore, the cross-section of the longitudinally heat conducting body is dot-shaped or star-shaped.

[0014] Furthermore, the longitudinally heat conducting body is a split filling structure or a graphene puncture structure.

[0015] Furthermore, the longitudinally heat conducting body is a split filling structure, and a graphene winding body is provided longitudinally in the longitudinally heat conducting body.

[0016] Furthermore, the longitudinally heat conducting body is a split filling structure, and the longitudinally heat conducting body is disposed directly behind the target.

[0017] Furthermore, the longitudinally heat conducting body is a graphene puncture structure, and a plurality of the longitudinally heat conducting bodies are dispersedly arranged.

[0018] Furthermore, the puncture directions of adjacent longitudinally heat conducting bodies are opposite, forming a geometric modulation structure with opposite directions.

[0019] Furthermore, one of the longitudinally heat conducting bodies is located at the center and is disposed directly behind the target, and the other longitudinally heat conducting bodies are uniformly arranged around the central longitudinally heat conducting body.

[0020] An X-ray tube includes the above-mentioned longitudinally split modulated graphene quasi-three-dimensional heat dissipation high thermal conductivity X-ray target.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] By using the longitudinally split modulated graphene quasi-three-dimensional heat dissipation high thermal conductivity X-ray target of the present invention as the X-ray target substrate, longitudinal high thermal conductivity can be achieved, and the heat dissipation capacity of the target substrate can be improved from two-dimensional heat dissipation to quasi-three-dimensional heat dissipation. Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of an existing X-ray source;

[0024] Figure 2 is a heat dissipation principle diagram of an existing X-ray source with a two-dimensional heat dissipation plate and a cooling system;

[0025] Figure 3It is the heat dissipation schematic diagram of the two-dimensional heat spreader in the existing X-ray source;

[0026] Figure 4 It is the schematic structural diagram of the longitudinal heat conductor of the split filling structure in the present utility model;

[0027] Figure 5 is Figure 4 the cross-sectional view of the two-dimensional heat spreader in

[0028] Figure 6 It is the schematic structural diagram of the graphene winding body arranged in the longitudinal heat conductor;

[0029] Figure 7 It is the structural comparison diagram of the longitudinal heat conductor with the graphene puncture structure and the prior art;

[0030] Figure 8 It is the heat dissipation schematic diagram of the longitudinal heat conductor with the graphene puncture structure and the prior art;

[0031] Figure 9 It is the cross-sectional view of the two-dimensional heat spreader with the longitudinal heat conductor of the graphene puncture structure.

[0032] Markings in the figure: 1 - cathode head; 2 - cathode; 3 - anode head; 4 - target; 5 - tube shell; 6 - heat dissipation matrix; 7 - electron beam; 8 - X-ray; 9 - cooling liquid; 10 - two-dimensional graphene heat spreader; 11 - longitudinal heat conduction; 12 - in-plane two-dimensional heat conduction; 13 - hot end; 14 - cold end; 15 - longitudinal heat conductor; 16 - two-dimensional graphene; 17 - graphene winding body. Detailed implementation manners

[0033] The present utility model will be further described in detail below with reference to the accompanying drawings.

[0034] The present utility model adopts the longitudinal split modulated graphene quasi-three-dimensional heat spread structure as the X-ray target matrix, improves the heat dissipation capacity of the target matrix from two-dimensional heat spread to quasi-three-dimensional heat spread, and proposes a transmission type high heat conduction target. By locally splitting the graphene, the longitudinal high heat conduction is realized in the way of longitudinal structure geometric modulation, and the longitudinal heat conduction performance is improved.

[0035] The longitudinal split modulated graphene quasi-three-dimensional heat conduction high heat conduction X-ray target of the present utility model mainly includes a heat dissipation matrix, a target arranged on the surface of the heat dissipation matrix, and a two-dimensional graphene heat spreader for in-plane two-dimensional heat conduction. The two-dimensional graphene heat spreader is arranged on the surface of the heat dissipation matrix, below the target. A longitudinal heat conductor for longitudinal heat conduction is arranged in the two-dimensional graphene heat spreader. A metallization layer is arranged on the surface of the two-dimensional graphene heat spreader, and the metallization layer is below the target.

[0036] One implementation structure of the longitudinal heat conductor is as Figure 4As shown in the figure, it is a split filling structure. The specific structure includes a heat dissipation base 6, a target 4, and a two-dimensional graphene heat spreader 10. The target 4 of the X-ray transmission target is attached to the two-dimensional graphene heat spreader 10 by means of vacuum coating, brazing, or casting. The two-dimensional graphene heat spreader 10 is disposed on the surface of the heat dissipation base 6 for in-plane two-dimensional heat conduction. The two-dimensional graphene heat spreader 10 is located below the target 4. A metallization layer is provided on the surface of the two-dimensional graphene heat spreader 10, and the metallization layer is located below the target 4. A longitudinal heat conductor 15 extending longitudinally is provided in the two-dimensional graphene heat spreader 10, and the longitudinal heat conductor 15 is used for longitudinal heat conduction. The two-dimensional graphene heat spreader 10 is punctured or star-shaped quasi-penetrated or penetrated in the central region of power deposition, as Figure 5 shown. At the split, copper or other high thermal conductivity metals are filled as the longitudinal heat conductor. In this embodiment, a copper longitudinal heat conductor is preferably used, and copper has good contact with the broken ends of the graphene weave. The longitudinal heat conductor 15 of the split filling structure compensates for the defect of the interlayer thermal conductivity of the graphene layer. The use of star-shaped splitting simultaneously increases the area of longitudinal heat conduction and the contact area between the longitudinal heat conductor and the two-dimensional heat dissipation layer, thereby significantly improving the overall thermal conductivity. Preferably, as Figure 6 shown, at the center position of the heat source, a longitudinal graphene winding body 17 can be synchronously filled in the longitudinal heat conductor 15, thereby further improving the longitudinal heat conductivity of the entire heat dissipation body.

[0037] One implementation structure of the longitudinal heat conductor is as Figure 7 shown, which is a graphene puncture structure. The specific structure includes a heat dissipation base 6, a target 4, and a two-dimensional graphene heat spreader 10. The target 4 of the X-ray transmission target is attached to the two-dimensional graphene heat spreader 10 by means of vacuum coating, brazing, or casting. The two-dimensional graphene heat spreader 10 is disposed on the surface of the heat dissipation base 6 for in-plane two-dimensional heat conduction. The two-dimensional graphene heat spreader 10 is located below the target 4. A metallization layer is provided on the surface of the two-dimensional graphene heat spreader 10, and the metallization layer is located below the target 4. The two-dimensional graphene 16 in the two-dimensional graphene heat spreader 10 is punctured to form a longitudinal heat conductor 15 extending longitudinally, and the longitudinal heat conductor 15 is used for longitudinal heat conduction. The two-dimensional graphene heat spreader 10 is locally punctured or star-shaped punctured and shaped, as Figure 9 shown, to construct a high-density graphene longitudinal orientation, and by simultaneously constructing geometric modulations in opposite directions, high longitudinal heat conduction performance is achieved. Figure 8 represents the improvement in longitudinal heat conduction performance brought about by constructing geometric modulations, and further the enhancement of two-dimensional heat conduction performance at the distal end (away from the target).

[0038] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A longitudinally split modulated graphene quasi-three-dimensional uniform heat-dissipating high thermal conductivity X-ray target, characterized in that: It includes a heat dissipation substrate, a target arranged on the surface of the heat dissipation substrate, and a two-dimensional graphene heat spreader for in-plane two-dimensional heat conduction. The two-dimensional graphene heat spreader is arranged on the surface of the heat dissipation substrate and is located below the target. The two-dimensional graphene heat spreader is provided with a longitudinal heat conductor extending longitudinally for longitudinal heat conduction.

2. The longitudinally split modulated graphene quasi-three-dimensional uniform heat-conductivity high thermal conductivity X-ray target according to claim 1, characterized in that: A metallization layer is provided on the surface of the two-dimensional graphene heat spreader, and the metallization layer is located below the target.

3. The longitudinally split modulated graphene quasi-three-dimensional uniform heat and high thermal conductivity X-ray target according to claim 1 or 2, characterized in that: The cross section of the longitudinal heat conductor is point-shaped or star-shaped.

4. The longitudinally split modulated graphene quasi-three-dimensional uniform heat and high thermal conductivity X-ray target according to claim 1 or 2, characterized in that: The longitudinal heat conductor is a split filling structure or a graphene puncture structure.

5. The longitudinally split modulated graphene quasi-three-dimensional uniform heat-conductivity high thermal conductivity X-ray target according to claim 4, characterized in that: The longitudinal heat conductor is a split filling structure, and a graphene winding body is arranged in the longitudinal direction of the longitudinal heat conductor.

6. The longitudinally split modulated graphene quasi-three-dimensional uniform heat-conductivity high thermal conductivity X-ray target according to claim 1, characterized in that: The longitudinal heat conductor is a split filling structure, and the longitudinal heat conductor is arranged right behind the target.

7. The longitudinally split modulated graphene quasi-three-dimensional uniform heat and high thermal conductivity X-ray target according to claim 1, characterized in that: The longitudinal heat conductor is a graphene puncture structure, and a plurality of the longitudinal heat conductors are dispersedly arranged.

8. The longitudinally split modulated graphene quasi-three-dimensional uniform heat and high thermal conductivity X-ray target according to claim 7, characterized in that: The puncture directions of adjacent longitudinal heat conductors are opposite to each other, forming a geometric modulation structure with opposite directions.

9. The longitudinally split modulated graphene quasi-three-dimensional uniform heat-conductivity high thermal conductivity X-ray target according to claim 7, characterized in that: One of the longitudinal heat conductors is located in the center and is arranged directly behind the target, and the other longitudinal heat conductors are evenly arranged around the central longitudinal heat conductor.

10. A ray tube, characterized in that: A longitudinally split and modulated graphene quasi-three-dimensional uniform heat and high thermal conductivity X-ray target comprising the above-mentioned claim 1.

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