阅读说明：本技术 一种阴栅组件及电子枪 (Shadow mask assembly and electron gun ) 是由 何大勇 王盛昌 肖欧正 李京祎 于 2021-09-16 设计创作，主要内容包括：本申请的实施例公开了一种阴栅组件及电子枪,所述阴栅组件包括壳体、位于所述壳体内的栅极部件和阴极部件；所述栅极部件包括栅网和散热环,所述栅网设置于所述散热环的一个开口处；所述阴极部件包括阴极和用于加热所述阴极的热子,所述阴极靠近所述栅网且与所述栅网之间具有间隙,所述阴极的发射面朝向所述栅网,其中,所述阴极和所述热子位于所述散热环的中空部。本申请通过设置与栅网固定连接以及包裹阴极和热子的散热环,增加了栅极部件的散热性能,使得阴栅组件能够实现高流强电子束的引出。(The embodiment of the application discloses a cathode grid assembly and an electron gun, wherein the cathode grid assembly comprises a shell, a grid part and a cathode part, wherein the grid part and the cathode part are positioned in the shell; the grid part comprises a grid mesh and a heat dissipation ring, and the grid mesh is arranged at one opening of the heat dissipation ring; the cathode component comprises a cathode and a heater for heating the cathode, the cathode is close to the grid mesh, a gap is formed between the cathode and the grid mesh, an emitting surface of the cathode faces the grid mesh, and the cathode and the heater are located in the hollow portion of the radiating ring. This application through set up with grid fixed connection and parcel negative pole and the radiating ring of heater, has increased the heat dispersion of grid part for the extraction of high current forceful electron beam can be realized to the negative grid subassembly.)

1. A shadow mask assembly comprising a housing, a mask member and a cathode member positioned within said housing;

the grid part comprises a grid mesh and a heat dissipation ring, and the grid mesh is arranged at one opening of the heat dissipation ring;

the cathode component comprises a cathode and a heater for heating the cathode, the cathode is close to the grid mesh, a gap is formed between the cathode and the grid mesh, an emitting surface of the cathode faces the grid mesh, and the cathode and the heater are located in the hollow portion of the radiating ring.

2. The shadow mask assembly of claim 1, wherein the mask comprises a matrix having a mesh shape, a support part for supporting the matrix is provided between the matrix and the opening, and the distance between the matrix and the cathode is adjusted by adjusting the thickness of the support part.

3. The shadow mask assembly of claim 1, wherein said cathode assembly further comprises a first support cylinder and a cathode cylinder inside said first support cylinder;

the cathode cylinder comprises a peripheral wall part and a bottom part for closing one end opening of the peripheral wall part, the cathode is arranged on the surface of the bottom part facing the grid mesh, the thermite is arranged in the cathode cylinder, the inner wall of the cathode cylinder is electrically connected with a first pin of the thermite, and the outer wall of the cathode cylinder is connected with the first support cylinder;

the cathode cylinder and at least part of the first supporting cylinder are positioned in the hollow part of the heat dissipation ring.

4. The shadow mask assembly of claim 3 wherein said first support cylinder is comprised of a plurality of metal sheets spaced circumferentially around said cathode cylinder.

5. The shadow mask assembly according to claim 3, wherein the cathode assembly further comprises a second supporting cylinder, the second supporting cylinder comprises a bottom wall parallel to the bottom of the cathode cylinder and a side wall disposed on the outer peripheral side of the bottom wall and extending from the bottom wall to the first supporting cylinder, the bottom wall is provided with a wiring cylinder extending to the first supporting cylinder, and the wiring cylinder is electrically connected to the second pin of the heater.

6. The shadow mask assembly of claim 5 further comprising seals respectively connected to said grid section and said cathode section to secure said cathode section in said housing;

the sealing piece comprises a first cylindrical structure and a second cylindrical structure which are coaxially arranged and connected, the second cylindrical structure comprises a first part and a second part, the first part is located in the first cylindrical structure, the second part extends out of the first cylindrical structure, a cavity is limited by the first cylindrical structure, a second supporting cylinder is accommodated in the cavity and is connected with the top surface of the first part through a first insulating piece, the second part is connected with the first supporting cylinder, and the bottom surface of the first cylindrical structure is connected with the radiating ring through a second insulating piece.

7. The shadow mask assembly according to claim 6, wherein a first step is formed on an outer side wall of said second portion, and an end of said first supporting cylinder remote from said cathode cylinder is fixed at said first step.

8. The shadow grid assembly of claim 6, wherein the first and second insulating members are ceramic rings.

9. The shadow mask assembly according to any one of claims 1 to 8, further comprising a flange disposed at the periphery of said housing.

10. An electron gun comprising the shadow mask assembly according to any one of claims 1 to 9.

Technical Field

The present application relates generally to the field of electron guns, and more particularly to a shadow mask assembly and an electron gun.

Background

The shadow mask assembly is a key part of an electron gun in the electron linear accelerator and is source equipment for generating electron beam current. In the working state, the grid in the cathode grid assembly needs to bear higher thermal power, and the thermal power mainly comes from the heat radiation of the cathode surface and the partial interception of the beam current by the grid. For high current cathode-grid assemblies, a larger area of the cathode is often selected to produce sufficient emission current, resulting in the grid being at a higher temperature due to more radiant heat power and more beam current being intercepted. Too high grid temperature can lead to grid high temperature deformation to lead to the interval between the bars of a shadow mask to diminish or the bar of a shadow mask short circuit takes place to the grid temperature reaches the melting point of grid solder can lead to the grid desoldering, and above problem makes the unable normal use of bar of a shadow mask subassembly even damage.

The structure of the existing shadow gate component makes the extraction of high-current strong electron beam difficult to realize.

Disclosure of Invention

In view of the above-mentioned drawbacks and deficiencies of the prior art, it is desirable to provide a cathode-grid assembly and an electron gun, so as to achieve extraction of high-current electron beam of the cathode-grid assembly by improving heat dissipation of a grid electrode.

As a first aspect of the present application, there is provided a cathode grid assembly comprising a housing, a grid section and a cathode section within the housing;

the grid part comprises a grid mesh and a heat dissipation ring, and the grid mesh is arranged at one opening of the heat dissipation ring;

the cathode component comprises a cathode and a heater for heating the cathode, the cathode is close to the grid mesh, a gap is formed between the cathode and the grid mesh, an emitting surface of the cathode faces the grid mesh, and the cathode and the heater are located in the hollow portion of the radiating ring.

Preferably, the grid comprises a grid-shaped base body, a supporting portion for supporting the base body is arranged between the base body and the opening, and the distance between the base body and the cathode is adjusted by adjusting the thickness of the supporting portion.

Preferably, the cathode component further comprises a first support cylinder and a cathode cylinder located inside the first support cylinder;

the cathode cylinder comprises a peripheral wall part and a bottom part for closing one end opening of the peripheral wall part, the cathode is arranged on the surface of the bottom part facing the grid mesh, the thermite is arranged in the cathode cylinder, the inner wall of the cathode cylinder is electrically connected with a first pin of the thermite, and the outer wall of the cathode cylinder is connected with the first support cylinder;

the cathode cylinder and at least part of the first support cylinder are positioned in the heat dissipation ring.

Preferably, the first support cylinder is composed of a plurality of metal sheets arranged at intervals around the circumference of the cathode cylinder.

Preferably, the cathode assembly further includes a second support cylinder, the second support cylinder includes a bottom wall parallel to the bottom of the cathode cylinder and a side wall disposed on an outer peripheral side of the bottom wall and extending from the bottom wall to the first support cylinder, the bottom wall is provided with a wiring cylinder extending to the first support cylinder, and the wiring cylinder is electrically connected to the second pin of the heater.

Preferably, the device further comprises sealing members respectively connected with the grid part and the cathode part so as to fix the cathode part in the shell;

the sealing piece comprises a first cylindrical structure and a second cylindrical structure which are coaxially arranged and connected, the second cylindrical structure comprises a first part and a second part, the first part is located in the first cylindrical structure, the second part extends out of the first cylindrical structure, a cavity is limited by the first cylindrical structure, a second supporting cylinder is accommodated in the cavity and is connected with the top surface of the first part through a first insulating piece, the second part is connected with the first supporting cylinder, and the bottom surface of the first cylindrical structure is connected with the radiating ring through a second insulating piece.

Preferably, a first step is formed on an outer side wall of the second portion, and an end of the first support cylinder far away from the cathode cylinder is fixed at the first step.

Preferably, the first insulating member and the second insulating member are both ceramic rings.

Preferably, the shell further comprises a flange arranged on the periphery of the shell.

As a second aspect of the present application, there is provided an electron gun comprising a shadow mask assembly as described above.

The beneficial effect of this application:

this application through set up with grid fixed connection and parcel negative pole and the radiating ring of heater, has increased the heat dispersion of grid part for the extraction of high current forceful electron beam can be realized to the negative grid subassembly.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a shadow mask assembly according to an embodiment of the present application;

FIG. 2 is an exploded view of a shadow mask assembly according to an embodiment of the present application;

FIG. 3 is a top view of a shadow mask assembly according to an embodiment of the present application;

FIG. 4 is a cross-sectional view taken along the line of FIG. 3A-A;

FIG. 5 is a schematic perspective view of a grid according to an embodiment of the present application;

FIG. 6 is a top view of a grid according to one embodiment of the present application;

FIG. 7 is a perspective view of a seal member according to an embodiment of the present application;

FIG. 8 is a cross-sectional view of a seal member according to an embodiment of the present application.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

It should be noted that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in an orientation or positional relationship indicated in the drawings for convenience and simplicity of description only, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be considered as limiting.

It should be noted that in the description of the present application, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.

It should be noted that unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly and include, for example, fixed or removable connections or integral connections; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

An embodiment of the present application discloses a cathode grid assembly, please refer to fig. 1 to 4, which includes a housing 1, a grid part and a cathode part located in the housing 1; the grid part comprises a grid mesh 20 and a heat dissipation ring 21, and the grid mesh 20 is arranged at one opening of the heat dissipation ring 21; the cathode component comprises a cathode 30 and a heater 31 for heating the cathode 30, the cathode 30 is close to the grid 20 and has a gap with the grid 20, an emission surface of the cathode 30 faces the grid 20, and the cathode 30 and the heater 31 are located in the hollow part of the heat dissipation ring 21.

Specifically, the housing 1 is a cylindrical structure with two open ends, and the grid part is arranged at one end of the housing 1;

the heat dissipation ring 21 is a cylinder with a certain wall thickness, and defines a cavity 210 with a certain wall thickness, two ends of the cavity are open, and the grid mesh 20 is welded at one opening of the cavity 210; the cathode 30 and the heater 31 are positioned in the cavity 210, and a gap is formed between the cathode 30 and the inner wall of the cavity 210, so that the cathode part and the grid part are insulated from each other;

the emission surface of the cathode 30 faces the grid mesh 20, the heat of the cathode 30 is conducted to the grid mesh 20 in a heat radiation mode, the grid mesh 20 is fixedly connected with the radiating ring 21, the heat of the grid mesh 20 can be transferred to the radiating ring 21 to exert the radiating effect, and the radiating ring 21 has a certain wall thickness, so that the temperature is not easy to rise; in addition, the heat dissipation ring 21 wraps the cathode 30 and the heater 31, so that the heat shielding effect is exerted to a certain extent, the heat power lost by the heater 31 through heat radiation can be effectively reduced, and the better filament heat efficiency is achieved.

The cathode grid assembly of the embodiment can obviously reduce the heat of the grid electrode by arranging the heat dissipation ring 21, and ensure the normal work of the grid electrode, so that the cathode grid assembly of the embodiment can be configured with the cathode 30 with larger size, and the extraction of a high-current strong electron beam is realized; the size of the cathode 30 can reach 16mm, and the electron beam intensity after the cathode grid assembly is led out can exceed 12A.

According to one embodiment of the application, the heat-dissipating ring 21 is stamped from kovar metal, has an inner diameter substantially corresponding to the outer diameter of the grill 20, has an outer diameter substantially greater than the outer diameter of the grill 20, such that it has a wall thickness large enough to transfer the thermal power of the grill 20 to the heat-dissipating ring 21 when it is welded to the grill 20, the large volume of the heat-dissipating ring 21 makes it less likely to increase in temperature, and its large surface area allows a large amount of heat to be dissipated outward.

According to one embodiment of the application, the cathode has a diameter of 16.2mm and an area of 2cm²The inner diameter of the heat dissipation ring 21 is 18mm, the outer diameter thereof is 32mm, and the height thereof (two ends are opened)Distance between the mouths) of 7.5mm and a volume of 4cm³The heat dissipation ring 21 has a sufficiently large surface area, and has a significant heat dissipation effect and a low tendency to increase its temperature.

Further, in some embodiments of the present application, referring to fig. 5 and 6, the grid 20 includes a grid-shaped base 200, a supporting portion for supporting the base 200 is disposed between the base 200 and the opening, and the distance between the base 200 and the cathode 30 is adjusted by adjusting the thickness of the supporting portion.

In some embodiments, the support portion is a protrusion formed on the end surface of the heat dissipating ring 21 for providing the opening of the grill 20, and the surface of the base 200 facing the heat dissipating ring 21 is welded to the protrusion, thereby fixing the base 200 at the opening of the heat dissipating ring.

For example, a support portion may be formed on an end surface of the opening in advance and then the base 200 may be fixed to the support portion in the form of soldering, or the support portion may be formed of solder during soldering of the base 200 to the opening, and a thickness of the support portion may be adjusted by adjusting an amount of the solder accumulated at the opening.

In other embodiments, the supporting portion is a fixing frame 201 disposed around the base 200 and is a component of the grid, that is, the grid 20 includes a grid-shaped base 200 and a fixing frame 201 disposed around the base 200, the fixing frame 201 is fixed at the opening, and the fixing frame 201 is configured to have a thickness for adjusting a distance between the base 200 and the cathode 30.

Specifically, the fixing frame 201 is a circular ring structure with a certain thickness, and has a front face 2011 and a back face 2012 which are opposite to each other, the base 200 is welded on the back face 2012 of the fixing frame 201, and the fixing frame 201 can ensure that the mesh surface of the base 200 is flat, so that the base 200 is not easy to distort and deform; the grid mesh 20 is fixed at the opening of the radiating ring 21 by welding in a way that the front surface of the fixing frame 201 faces the radiating ring 21, the base 200 and the surface of the cathode 30 keep a close distance so as to bear a large amount of outward thermal radiation heat transfer of the surface of the cathode 30, therefore, the base 200 with the highest temperature in the grid part is the fixing frame 201, the heat on the base 200 is transferred to the radiating ring 21 through the fixing frame 201, and the radiating ring 21 plays a role in radiating;

wherein, because fixed frame 201 has certain thickness for have the interval between base member 200 and the negative pole 30, the thickness of accessible regulation fixed frame 201 makes the distance between base member 200 and the negative pole 30 emission face adjusted, and wherein, the thickness of fixed frame 201 can be 0.3 ~ 2mm, preferably 0.5 ~ 1 mm.

According to an embodiment of the present application, the fixing frame 201 is made of molybdenum, which has high mechanical strength and can sufficiently fix the base 200.

According to an embodiment of the present application, the latticed base 200 is formed by weaving a plurality of metal wires, a plurality of grids (or grid holes) are formed between the metal wires after the metal wires are staggered, the space between the grids is small, and the space between the grids can be realized by adjusting the diameters of the metal wires and the space between the metal wires, so that not only can the grid 20 with a small enough grid space be conveniently obtained, but also the accuracy of size regulation and control of the grid 20 is high.

It will be appreciated that in other embodiments, the mesh-like substrate 200 may be formed by wire bonding, or by making holes in a metal sheet.

According to one embodiment of the present application, the diameter of the wire is 0.02 to 0.03mm, so that the wire grid 20 of the present application has a sufficiently small grid pitch.

According to one embodiment of the application, the distance between two adjacent metal wires is 0.17-0.18 mm, wherein the adjustment of the grid size can be realized by adjusting the distance between two adjacent metal wires.

According to one embodiment of the application, the metal wire is a gold plated tungsten rhenium wire.

According to an embodiment of the present application, referring to fig. 6, the grid 20 further includes a reinforcing member 202 for preventing deformation of the substrate 200, and the reinforcing member 202 is welded to the substrate 200 to prevent or reduce deformation of the substrate 200 at high temperature.

The stiffener 202 includes a stiffener ring 2021 and a stiffener 2022, the stiffener ring 2021 is disposed concentrically with the base 200, one end of the stiffener 2022 is connected to the stiffener ring 2021, and the other end extends to the fixing frame 201.

Specifically, the reinforcement ring 2021 is connected to the surface of the base 200 facing away from the fixing frame 201 by welding, and the center of the reinforcement ring 2021 is concentric with the center of the base 200, one end of the reinforcement 2022 is connected to the reinforcement ring 2021, and the other end extends toward the fixing frame 201, and the reinforcement 202 not only prevents the base 200 from being thermally deformed, but also helps the thermal power at the center of the grid 20 to be conducted to the edge of the grid 20, thereby reducing the temperature at the center area of the grid 20; wherein the reinforcement ring 2021 and the reinforcement rib 2022 may be integrally formed, or may be formed as separate elements, and are joined together by any suitable means, such as by welding;

the shape of the reinforcement ring 2021 is to be understood in a broad sense, and it is not limited to a circular ring, and may be a rectangular ring structure, a triangular or other polygonal ring structure, whose size, for example, inner diameter is determined according to the size of the mesh, and whose shape may be the same as or different from that of the fixed frame 201.

According to one embodiment of the application, the reinforcement ring 2021 and the reinforcement ribs 2022 are made of wires having a diameter of 0.2 mm.

According to an embodiment of the present application, the number of the reinforcing ribs 2022 is plural, and the reinforcing ribs are uniformly distributed between the reinforcing ring 2021 and the fixing frame 201 along the circumferential direction of the reinforcing ring 2021.

According to one embodiment of the application, as shown in fig. 5, the number of said reinforcement ribs 2022 is 6, evenly distributed in the ring between the reinforcement ring 2021 and the fixed frame 201 at 60 ° intervals.

According to an embodiment of the present application, the end of the reinforcing rib 2022 extending to the fixing frame 201 has a tab 2023, and the tab 2023 is connected to the base 200. The sheet part 2023 can be connected to the base 200 by welding, and the provision of the sheet part 2023 can increase the contact area between the end of the reinforcing rib 2022 extending to the fixing frame 201 and the base 200, enhance the connection reliability between the reinforcing rib 2022 and the base 200, prevent the connection point (e.g., welding point) between the reinforcing rib 2022 and the base 200 from being broken, and prevent the grid 20 from failing in a high-temperature environment;

according to an embodiment of the application, the tab 2022 is a molybdenum metal tab with a thickness of 0.2 mm; wherein the reinforcement ring 2021, the bead 2022 and the flap 2023 may be formed as separate elements, connected together by any suitable means, such as by welding, preferably the reinforcement ring, the bead and the flap being integrally formed.

According to an embodiment of the present application, after the grid 20 of the present application is fixed at the opening of the heat dissipation ring 21, the fixing frame 201, the base 200 and the reinforcement 202 are stacked in order from the near to the far from the cathode 30, that is, the grid 20 is disposed in the cathode-grid assembly in a manner that the front 2011 of the fixing frame 201 faces the cathode 30; the thickness of the fixing frame 201 is 0.3-2 mm, preferably 0.5-1 mm, so that a sufficient distance is formed between the plane of the latticed base body 200 and the emitting surface of the cathode 30, and the short-pulse electron beam current can be conveniently led out by applying pulse voltage between the cathode surface and the grid mesh.

The pulse voltage directly applied to the cathode and the grid does not exceed 1kV at most, so that the pulse power supply can realize the pulse high voltage with the FWHM pulse width of only 1ns, and for an electron gun directly adopting a cathode and anode bipolar structure, the nanosecond-level beam extraction is difficult to realize by directly passing through the pulse high voltages of the cathode and the anode.

According to one embodiment of the present application, the fixing frame 201 is a circular ring structure, the outer diameter of the circular ring is 20.8mm, the inner diameter of the circular ring is 17.4mm, the thickness is 1mm, the diameter of the cathode 30 corresponding to the grid with the fixing frame 201 is 16.2mm at the maximum, and the distance between the emitting surface of the cathode 30 and the grid 20 is 0.16 mm.

Further, in some embodiments of the present application, the cathode assembly further comprises a first support cylinder 32 and a cathode cylinder 33 located inside the first support cylinder 32;

the cathode cylinder 33 comprises a peripheral wall part 330 and a bottom part 331 closing one end opening of the peripheral wall part 330, the cathode 30 is arranged on the surface of the bottom part 331 facing the grid 20, the heater 31 is arranged in the cathode cylinder 33, the inner wall of the cathode cylinder 33 is electrically connected with a first pin (not shown) of the heater 21, and the outer wall of the cathode cylinder 33 is connected with the first support cylinder 32;

the cathode cylinder 33 and at least a portion of the first support cylinder 32 are located within the heat sink ring 21.

Specifically, referring to fig. 2, the cathode cylinder 33 is a carrier for carrying the cathode 30 and the thermite 31, and is a cylindrical structure with one open end, the cathode 30 is welded on the surface of the bottom 331 of the cathode cylinder 33 facing the grid 20, the thermite 31 in a cake shape is arranged in the cathode cylinder 33, the thermite 31 is close to the cathode 30 and is separated by the bottom 331, a first pin of the thermite 31 is welded to the inner wall of the cathode cylinder 33 to form a common potential point, and a second pin 310 of the thermite 31 is led out from the cathode cylinder 33; the cathode cylinder 33 is made of an electrically conductive material and is configured as a component of a filament circuit.

The first supporting cylinder 32 is sleeved on the cathode cylinder 33, the inner wall surface of the first supporting cylinder 32 is welded with the outer wall surface of the bottom 331 of the cathode cylinder 33, and after the cathode cylinder 33 is connected with the first supporting cylinder 32 as the first pin of the heater 31 is electrically connected with the cathode cylinder 33, the first supporting cylinder 32 is configured to be the extension of the first pin of the heater 31;

the first supporting cylinder 32 plays a supporting role on one hand, can form stable and reliable support for the cathode 30 and the heater 31, and avoids cathode surface displacement or short circuit between cathode grids in the long-time use process of the cathode grid assembly; on the other hand, the first support cylinder 32 and the cathode cylinder 33 form a two-layer heat shield structure, so that the heat power lost by the thermions 31 through heat radiation is remarkably reduced, and the heat efficiency of the filament is improved.

The outer diameter of the first supporting cylinder 32 is slightly smaller than the inner diameter of the heat dissipating ring 21, and when the first supporting cylinder is located in the heat dissipating ring 21, an insulating gap is formed between the first supporting cylinder and the heat dissipating ring 21, so that the insulation between the grid part and the cathode part is ensured.

Further, in some embodiments of the present application, referring to fig. 2, the first support cylinder 32 is composed of a plurality of metal sheets spaced around the cathode cylinder 33, and the metal sheets may be molybdenum-rhenium alloy sheets with a thickness of 0.02-0.1 mm.

Further, in some embodiments of the present application, the cathode assembly further includes a second supporting cylinder 34, the second supporting cylinder 34 includes a bottom wall 340 parallel to the bottom 331 of the cathode cylinder 33 and a sidewall 341 disposed on an outer circumferential side of the bottom wall 340 and extending from the bottom wall 340 to the first supporting cylinder 32, a wiring cylinder 342 extending to the first supporting cylinder 32 is disposed on the bottom wall 340, and the wiring cylinder 342 is electrically connected to the second pin 310 of the heater 31.

Specifically, referring to fig. 2, the second supporting cylinder 34 is a cylindrical structure with an open end, and a wire connecting cylinder 342 is disposed inside the second supporting cylinder 34, wherein one end of the wire connecting cylinder 342 is connected to the bottom wall 340 of the second supporting cylinder 34, and the other end extends toward the first supporting cylinder 32 and is connected to the second pin 310 of the heater 31;

the second supporting cylinder 34 is made of a conductive material, and not only serves as a connection end of the filament circuit, but also serves as a vacuum isolation component, and can be matched with a flange to enable the cathode 30 and the heater 31 to be in a vacuum environment, and after the cathode grid assembly is mounted on the electron gun, the cathode 30 of the cathode grid assembly can be in a required high-vacuum environment through a vacuum pumping system in the electron gun.

Further, in some embodiments of the present application, a sealing member 4 is further included, which is connected to the grid member and the cathode member, respectively, to fix the cathode member in the housing 1;

the sealing member 4 comprises a first cylindrical structure 40 and a second cylindrical structure 41 which are coaxially arranged and connected, the second cylindrical structure 41 comprises a first part 410 positioned in the first cylindrical structure 40 and a second part 411 extending out of the first cylindrical structure 40, the first cylindrical structure 40 defines a cavity 400, the second supporting cylinder 34 is accommodated in the cavity 400 and connected with the top surface of the first part 410 through a first insulating member 50, the second part 411 is connected with the first supporting cylinder 32, and the bottom surface of the first cylindrical structure 40 is connected with the radiating ring 21 through a second insulating member 51.

Specifically, referring to fig. 7 and 8, the sealing member 4 includes a first cylindrical structure 40 and a second cylindrical structure 41 which are coaxially disposed and have openings at two ends, a portion of the second cylindrical structure 41 extends outside the first cylindrical structure 40, the first cylindrical structure 40 is connected to an outer wall of the second cylindrical structure 41 at one opening thereof through a metal ring, and the first cylindrical structure 40 and the second cylindrical structure 41 are both made of conductive materials;

the second supporting cylinder 34 is located in the cavity 400 of the first cylindrical structure 40, and the opening of the second supporting cylinder is facing the heater 31, and the second pin 310 of the heater 31 penetrates through the channel inside the second cylindrical structure 41 and is connected to the wiring cylinder 342; the second supporting cylinder 34 and the first supporting cylinder 32 are respectively welded with the first part 410 and the second part 411 of the sealing member 4, the second supporting cylinder 34 is electrically connected with the second pin 310 of the heater 31, the first supporting cylinder 32 is indirectly electrically connected with the first pin of the heater 31, the insulation of two ends of a heater circuit is ensured through the first insulating member 50, and the two poles of the filament circuit are prevented from forming a short circuit;

the bottom of the end part of the first cylindrical structure 40 close to the first supporting cylinder 32 is welded with the end part of the radiating ring 21 far away from the grid mesh 20 through a second insulating piece 51, the first supporting cylinder 32 is indirectly and electrically connected with the first pin of the heater 31 because the second part 411 is welded with the first supporting cylinder 32, and the insulation between the grid part and the cathode part (particularly, a heater circuit) is ensured through the second insulating piece 51;

the sealing member 4 plays a role of fixedly supporting the cathode member, fixes the cathode member at the center of the housing 1, and realizes an insulating function between three ends of the cathode-grid assembly by cooperation with the first insulating member 50 and the second insulating member 51.

Further, in some embodiments of the present application, referring to fig. 8, a first step 4111 is formed on an outer side wall of the second portion 411, and an end of the first support cylinder 32 away from the cathode cylinder 33 is fixed at the first step 4111.

Further, in some embodiments of the present application, the first insulator 50 and the second insulator 51 are both ceramic rings.

The ceramic has excellent electrical insulation and thermal stability, gives sufficient stability to the grid assembly while exerting an insulation effect, and enhances the connection sealability between the components.

Further, in some embodiments of the present application, a flange 6 is further included, which is disposed at the periphery of the housing 1.

Specifically, referring to fig. 1, the flange 6 is fixed to the upper end (the other end away from the grid part) of the housing 1, and the flange 6 is a CF35 flange.

The cathode-grid assembly is an electric vacuum device, the working environment of the cathode part and the working environment of the grid part are high vacuum environment (the static vacuum degree is better than 1E-7Pa), the vacuum isolation function is formed by matching the flange 6, the shell 1, the sealing piece 4, the first insulating piece 50, the second insulating piece 51, the grid part and the like, the cathode-grid assembly can be installed on the electron gun through the matching of the flange 6 and a corresponding flange interface of the electron gun to complete vacuum sealing, and the cathode part and the grid part of the cathode-grid assembly can be in the required high vacuum environment through a vacuum pumping system in the electron gun.

Further, in some embodiments of the present application, the heater 31 includes a filament and a sintered porcelain wrapping the filament, and two ends of the filament extend out of the sintered porcelain to form the first pin and the second pin.

Specifically, the filament is a toroidal helical heating body formed by winding a tungsten-rhenium alloy wire, an insulating medium (such as alumina and corundum powder) for forming sintered porcelain wraps the filament, two ends of the filament extend out of the insulating medium, and the two parts are sintered at high temperature to form a whole, so that a cake-shaped heater 31 accommodated in a cathode cylinder 33 is formed.

Further, in some embodiments of the present application, the housing 1, the heat dissipation ring 21, the cathode cylinder 33, the first support cylinder 32, the second support cylinder 34, and the sealing member 4 are coaxially disposed.

The cathode-grid assembly of the embodiment of the application is provided with the heat dissipation ring 21, so that the heat of a grid part is obviously reduced, and the extraction of high-current strong electron beam current is realized; a small-sized shadow-grid structure is realized by adopting a CF35 flange; by arranging the grid part and the cathode part, short pulse high voltage below nanosecond level can be applied between the cathode and the anode, so that the extraction of short pulse electron beam current is realized, the electron beam current intensity after being extracted from the cathode and anode assembly exceeds 12A, and the pulse width of the electron beam can be as low as 1 ns.

Embodiments of the present application also disclose an electron gun comprising a shadow mask assembly as described above.

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.