阅读说明：本技术 一种适用于加速器的稳态高束流密度长寿命锂离子源 (Stable-state high-beam-density long-life lithium ion source suitable for accelerator ) 是由 胡广海 邵林明 陈良 王一丰 陈冉 于 2020-12-16 设计创作，主要内容包括：本发明提供了一种适用于加速器的稳态高束流密度长寿命锂离子源,包括：钼骨架、多孔基板、钨铼丝金属网；所述的钼骨架为圆桶形,包括顶部和环形外壁；所述钼骨架顶部设置有开槽,用于放置多孔基板,所述多孔基板采用钼粉和氧化铝粉末压制烧结而成；在钼骨架顶部凹槽周围设置有环形台阶,环形台阶上设置有多个开孔,钨铼丝多次穿过所述开孔编织成网状结构,锂霞石与去离子水混合物均匀涂在多孔基板结构表面并覆盖钨铼丝网,编织钨铼丝网与锂霞石涂层在真空环境下一同烧结,得到发射涂层,编织钨铼丝网与锂霞石涂层形成了类似钢筋混凝土结构,形成整体结构。本发明加强了发射材料与整体结构附着强度,提高了锂离子源的发射能力和使用寿命。(The invention provides a steady-state high-beam-current-density long-life lithium ion source suitable for an accelerator, which comprises: a molybdenum skeleton, a porous substrate and a tungsten-rhenium wire metal net; the molybdenum framework is in a barrel shape and comprises a top and an annular outer wall; the top of the molybdenum skeleton is provided with a slot for placing a porous substrate, and the porous substrate is formed by pressing and sintering molybdenum powder and alumina powder; the method comprises the steps of arranging an annular step around a groove in the top of a molybdenum skeleton, arranging a plurality of openings on the annular step, enabling a tungsten-rhenium wire to penetrate through the openings for multiple times to be woven into a net-shaped structure, uniformly coating a mixture of eucryptite and deionized water on the surface of a porous substrate structure and covering a tungsten-rhenium wire mesh, sintering the woven tungsten-rhenium wire mesh and the eucryptite coating together in a vacuum environment to obtain an emission coating, and forming a similar reinforced concrete structure by weaving the tungsten-rhenium wire mesh and the eucryptite coating to form an integral structure. The invention enhances the adhesion strength of the emission material and the whole structure, improves the emission capability of the lithium ion source and prolongs the service life of the lithium ion source.)

1. A steady-state high beam current density long life lithium ion source suitable for use in an accelerator, comprising: a molybdenum skeleton, a porous substrate and a tungsten-rhenium wire metal net; the molybdenum framework is in a barrel shape and comprises a top and an annular outer wall; the top of the molybdenum skeleton is provided with a slot for placing a porous substrate, and the porous substrate is formed by pressing and sintering molybdenum powder and alumina powder; the method comprises the steps of arranging an annular step around a groove in the top of a molybdenum skeleton, arranging a plurality of openings on the annular step, enabling a tungsten-rhenium wire to penetrate through the openings for multiple times to be woven into a net-shaped structure, uniformly coating a mixture of eucryptite and deionized water on the surface of a porous substrate structure and covering a tungsten-rhenium wire mesh, sintering the woven tungsten-rhenium wire mesh and the eucryptite coating together in a vacuum environment to obtain an emission coating, and forming a similar reinforced concrete structure by weaving the tungsten-rhenium wire mesh and the eucryptite coating to form an integral structure.

2. The steady-state high beam current density long life lithium ion source of claim 1 adapted for use in an accelerator, wherein: the porous molybdenum powder and the alumina are pressed into the porous structure substrate, the thermal expansion coefficient of the porous structure substrate is close to that of the molybdenum skeleton and eucryptite, the coating is not cracked due to expansion at high temperature, and the high temperature range is 1350-.

3. The steady-state high beam current density long life lithium ion source of claim 1 adapted for use in an accelerator, wherein: the framework is utilized to weave the tungsten-rhenium wire metal mesh, the coating and the metal mesh form a structure similar to reinforced concrete, and the coating is prevented from being stripped under the action of electrostatic force under high voltage.

4. The steady-state high beam current density long life lithium ion source of claim 1 adapted for use in an accelerator, wherein: under the combined action of the porous substrate and the tungsten-rhenium wire metal mesh, the thickness of the coating is increased, and the service life of the ion source is prolonged.

5. The steady-state high beam current density long life lithium ion source of claim 1 adapted for use in an accelerator, wherein: the porous substrate is formed by injecting a mixture of 75% molybdenum powder and 25% high-purity alumina powder into a cavity at the top of a molybdenum skeleton at a mass ratio of 10T/cm²And pressing the mixed powder into the cavity at the top part under pressure to form the porous substrate with a porous structure.

6. The steady-state high beam current density long life lithium ion source of claim 1 adapted for use in an accelerator, wherein: the thickness of the pressed porous substrate is half of the depth of the concave cavity; and slowly heating the molybdenum skeleton and the porous substrate to 1600 ℃ in a vacuum environment, maintaining the temperature for more than 6 hours, and then slowly cooling to room temperature, wherein the molybdenum skeleton and the porous substrate are sintered together.

Technical Field

The invention relates to a lithium ion accelerator on an EAST tokamak device, in particular to a lithium ion source with high beam density and long service life, which is suitable for the lithium accelerator.

Background

Obtaining the density and current distribution of boundary plasma without interference is an indispensable important physical quantity for researching the plasma. The electron density of plasma is measured internationally and generally by using a high-energy lithium neutral beam without interference and fixed points. The lithium ion source used at present is limited by the substrate material, the thickness of the emission material, the influence of the bonding strength of the emission material coating and the substrate, and the emission coating often has the problems of cracking, peeling and the like. To avoid these problems, it is often done by reducing the coating thickness, reducing the current emission capability. The thinner emission coating results in shorter ion source service life, unsatisfactory beam emission and greatly increased system maintenance time. The weak current emission simultaneously brings large measurement errors to the boundary electron density and the current distribution.

Therefore, the lithium ion source with high beam current density and long service life is an ideal solution for reducing the measurement error of the boundary electron density by using the lithium neutral beam. This requires that the lithium ion source does not crack between the emissive coating and the substrate at high temperatures, that the coating does not peel off from the substrate under high voltage operation, and that the coating thickness is significantly increased.

Disclosure of Invention

The invention aims to provide a method for manufacturing a lithium ion source suitable for an accelerator so as to realize high beam density emission, long service life and high-voltage working capacity of the lithium ion source.

In order to achieve the purpose, the invention adopts the technical scheme that: a steady-state high beam current density long life lithium ion source suitable for use in an accelerator comprising: a molybdenum skeleton, a porous substrate and a tungsten-rhenium wire metal net; the molybdenum framework is in a barrel shape and comprises a top and an annular outer wall; the top of the molybdenum skeleton is provided with a slot for placing a porous substrate, and the porous substrate is formed by pressing and sintering molybdenum powder and alumina powder; the method comprises the steps of arranging an annular step around a groove in the top of a molybdenum skeleton, arranging a plurality of openings on the annular step, enabling a tungsten-rhenium wire to penetrate through the openings for multiple times to be woven into a net-shaped structure, uniformly coating a mixture of eucryptite and deionized water on the surface of a porous substrate structure and covering a tungsten-rhenium wire mesh, sintering the woven tungsten-rhenium wire mesh and the eucryptite coating together in a vacuum environment to obtain an emission coating, and forming a similar reinforced concrete structure by weaving the tungsten-rhenium wire mesh and the eucryptite coating to form an integral structure.

Furthermore, the porous molybdenum powder and the alumina are pressed into the porous structure substrate, the thermal expansion coefficient of the porous structure substrate is close to that of the molybdenum skeleton and the eucryptite, the coating is not cracked due to expansion at high temperature, and the high temperature range is 1350-.

Furthermore, the tungsten-rhenium wire metal mesh is woven by utilizing the framework, the coating and the metal mesh form a structure similar to reinforced concrete, and the coating is prevented from being stripped under the action of electrostatic force under high voltage.

Furthermore, under the combined action of the porous substrate and the tungsten-rhenium wire metal mesh, the thickness of the coating is increased, and the service life of the ion source is prolonged.

Furthermore, the porous substrate is formed by injecting a mixture of 75% molybdenum powder and 25% high-purity alumina powder into the cavity at the top of the molybdenum skeleton at a mass ratio of 10T/cm²And pressing the mixed powder into the cavity at the top part under pressure to form the porous substrate with a porous structure.

Further, the thickness of the pressed porous substrate is half of the depth of the concave cavity; and slowly heating the molybdenum skeleton and the porous substrate to 1600 ℃ in a vacuum environment, maintaining the temperature for more than 6 hours, and then slowly cooling to room temperature, wherein the molybdenum skeleton and the porous substrate are sintered together.

Has the advantages that:

1. the invention opens a groove on the top of the high temperature resistant and firm cylindrical molybdenum skeleton, presses the molybdenum powder and the alumina powder into the porous structure substrate and sinters at high temperature to form an integral structure. The holes are formed in the periphery of the steps at the top of the molybdenum skeleton, the tungsten-rhenium wires can pass through the holes in a certain number for multiple times to be woven into a net structure, and the tungsten-rhenium wires still have good flexibility and cannot be cracked after working at high temperature. The mixture of the high-purity eucryptite and the deionized water is uniformly coated on the surface of the porous substrate structure and covered with the tungsten-rhenium wire mesh, the mixture is sintered again in a high-temperature and vacuum environment, the rough surface of the porous substrate has good fitting degree with the eucryptite coating, and the tungsten-rhenium wire mesh and the eucryptite coating form a similar reinforced concrete structure to form an integral structure.

2. The porous molybdenum powder and the alumina are pressed into the porous structure substrate, the thermal expansion coefficient of the porous structure substrate is close to that of a molybdenum skeleton and eucryptite, and the coating is prevented from cracking due to expansion at high temperature.

3. The framework is utilized to weave the tungsten-rhenium wire metal mesh, and the coating and the metal mesh form a structure similar to reinforced concrete, so that the coating can be ensured not to be stripped under the action of electrostatic force under high voltage.

4. Under the combined action of the porous substrate and the tungsten-rhenium wire metal mesh, the thickness of the coating can be greatly increased, and the service life of the ion source is greatly prolonged.

Drawings

FIG. 1 is a cross-sectional view of a steady-state high beam current density long life lithium ion source suitable for use in an accelerator according to the present invention;

fig. 2 is an exploded view of a lithium ion source of the present invention.

Wherein: 1 molybdenum skeleton, 2 porous base plates, 3 tungsten-rhenium wire metal meshes, 4 emission coatings and 5 wire through holes.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by a person skilled in the art based on the embodiments of the present invention belong to the protection scope of the present invention without creative efforts.

As shown in fig. 1-2, according to an embodiment of the present invention, there is provided a steady-state high beam density long life lithium ion source suitable for an accelerator, comprising a high mechanical strength molybdenum skeleton 1, a molybdenum powder and alumina powder press-sintered porous substrate 2, a tungsten-rhenium wire gauze 3, a high purity eucryptite powder sintered emission coating 4, and wire passing holes 5 on the molybdenum skeleton 1 for weaving the tungsten-rhenium wire gauze. The base plate made of the molybdenum skeleton 1, molybdenum and aluminum oxide powder and the emitting coating have similar thermal expansion coefficients, so that the adhesiveness of the emitting material on the base plate can be ensured, and the emitting material can not crack due to thermal expansion. The tungsten-rhenium wire metal mesh and the eucryptite emitting material are sintered together to form a structure similar to reinforced concrete, so that the emitting material is ensured not to peel off the ion source framework under the action of electrostatic force.

According to one embodiment of the invention, the high-mechanical-strength molybdenum skeleton 1 is made of high-reflectivity molybdenum material, is barrel-shaped and comprises a top part and an annular outer wall; an annular concave cavity is arranged at the top, the depth of the concave cavity is 4mm, an annular step is arranged around the concave cavity, and the height of the step is 2mm, and the width of the step is 1.5 mm.

According to one embodiment of the invention, the porous substrate 2 is prepared by injecting a mixture of 75% by mass of high-purity molybdenum powder with a diameter of 50 microns and 25% by mass of high-purity alumina powder into the cavities at the top of the molybdenum skeleton at a rate of 10T/cm²The mixed powder is pressed into the top cavity under pressure to form the porous substrate 2 of porous structure. The thickness of the porous substrate 2 after pressing is half the depth of the cavity. The molybdenum skeleton 1 and the porous substrate 2 are slowly heated to 1600 ℃ in a vacuum environment, the temperature is maintained for more than 6 hours, and then the temperature is slowly reduced to the room temperature. The molybdenum skeleton 1 and the porous substrate 2 are sintered together, and the molybdenum skeleton 1 and the porous substrate 2 have similar compositions, so that the expansion coefficients are close, and the separation of the molybdenum skeleton and the porous substrate caused by the different thermal expansion coefficients is relieved.

According to one embodiment of the invention, holes are formed in the circumference of the molybdenum skeleton 1 in a step mode, and tungsten-rhenium wires with the diameter of 0.2mm penetrate through each metal hole to be woven into a metal mesh. The tungsten-rhenium wire can still keep stronger toughness and mechanical strength under multiple times of heating.

According to one embodiment of the present invention, high purity (99.5%) eucryptite powder is stirred with deionized water and then filled into the molybdenum skeleton step cavity, which can adhere to the porous substrate and form a structure similar to reinforced concrete with tungsten-rhenium wire mesh 3. With this structure, the thickness of the surface coating can reach 1-2 mm. The surface coating was slowly dried in the shade over 48 hours at room temperature so that the powder coating did not dry out.

According to one embodiment of the invention, the prepared ion source framework is placed into a vacuum furnace, slowly heated to 1415 ℃ for 120 minutes, maintained at the temperature for 10 minutes, and then slowly cooled to a room temperature state. Through the steps, the lithium ion source is manufactured.

Although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, but various changes may be apparent to those skilled in the art, and it is intended that all inventive concepts utilizing the inventive concepts set forth herein be protected without departing from the spirit and scope of the present invention as defined and limited by the appended claims.