阅读说明：本技术 一种新的直线感应加速腔结构 (Novel linear induction accelerating cavity structure ) 是由 陈思富 黄子平 李欣 何佳龙 叶毅 蒋薇 吕璐 刘尔祥 于 2020-12-08 设计创作，主要内容包括：本发明公开了一种新的直线感应加速腔结构,包括铁磁室,铁磁室内设有磁芯组,磁芯组包括铁氧体磁芯和非晶磁芯。本发明与现有技术相比,具有如下的优点和有益效果：横向阻抗大大降低,不需要像常规非晶磁芯感应腔那样采用增加束管道半径的方式来降低非晶磁芯感应腔的横向耦合阻抗以满足强流束的输运要求；铁氧体磁性材料近似绝缘材料且它将非晶磁芯与高压馈入板隔开,这大幅度增加了非晶磁芯感应加速腔的耐压能力；结构紧凑、可靠,既可用于短脉冲,也可用于长脉冲、多脉冲等需要提供更多伏秒数的情形；与现有感应腔相比,可以减小磁芯的用量,提高加速梯度,减少加速器的长度,利于强流束的传输,同时大幅降低加速器的造价。(The invention discloses a novel linear induction accelerating cavity structure which comprises a ferromagnetic chamber, wherein a magnetic core group is arranged in the ferromagnetic chamber, and the magnetic core group comprises a ferrite magnetic core and an amorphous magnetic core. Compared with the prior art, the invention has the following advantages and beneficial effects: the transverse impedance is greatly reduced, and the transverse coupling impedance of the amorphous magnetic core induction cavity is reduced by adopting a mode of increasing the radius of a beam pipeline to meet the transportation requirement of a strong beam like a conventional amorphous magnetic core induction cavity; the ferrite magnetic material is similar to an insulating material and separates the amorphous magnetic core from the high-voltage feed plate, so that the voltage resistance of the amorphous magnetic core induction accelerating cavity is greatly improved; the structure is compact and reliable, and the device can be used for short pulses, long pulses, multi-pulse and other situations needing to provide more volt-seconds; compared with the existing induction cavity, the induction cavity can reduce the using amount of the magnetic core, improve the acceleration gradient, reduce the length of the accelerator, facilitate the transmission of the strong flux beam and greatly reduce the manufacturing cost of the accelerator.)

1. The utility model provides a new cavity structure is accelerated in straight line response, includes ferromagnetic chamber, is equipped with the magnetic core group in the ferromagnetic chamber, its characterized in that: the magnetic core group comprises a ferrite magnetic core (2) and an amorphous magnetic core (3).

2. The new linear induction acceleration chamber structure of claim 1 characterized by: the ferrite magnetic core (2) is positioned between the amorphous magnetic core (3) and the acceleration gap.

3. The new linear induction acceleration chamber structure of claim 2, characterized in that: the ferrite magnetic core (2) is positioned between the amorphous magnetic core (3) and a high-voltage feeding plate (9) forming an accelerating gap.

4. The new linear induction acceleration chamber structure of claim 1, 2 or 3, characterized by: the ferrite magnetic core (2) is provided with one block.

5. The new linear induction acceleration chamber structure of claim 1, 2 or 3, characterized by: the housing (4), the short-circuit disc I (5), the middle shell (6) and the high-voltage feed plate (9) form a ferromagnetic chamber.

6. The new linear induction acceleration chamber structure of claim 1 characterized by: still include the coil room, be equipped with coil assembly in the coil room.

7. The new linear induction acceleration chamber structure of claim 6, characterized in that: the coil assembly comprises a helical coil and a correction coil.

8. The new linear induction acceleration chamber structure of claim 1, 6 or 7, characterized by: the short circuit disc I (5), the middle shell (6), the inner shell (8) and the high voltage feed plate (9) form a coil chamber.

9. The new linear induction acceleration chamber structure of claim 2 or 3, characterized by: the high-voltage feed plate (9) and the short-circuit disc II (11) form an acceleration gap.

10. The new linear induction acceleration chamber structure of claim 2 or 3, characterized by: an insulating ring (10) is arranged in the accelerating gap.

Technical Field

The invention relates to a high-current linear induction accelerator, in particular to a novel linear induction acceleration cavity structure.

Background

The linear induction accelerator is a strong current pulse accelerator with a building block structure developed in 60 s of the 20 th century to generate strong current pulse charged particle beams. Taking an electron linear induction accelerator as an example, the current intensity of the generated pulsed electron beam is several kA, the energy is several tens MeV, and the pulse width is several tens ns to several μ s.

The accelerating section of the linear induction accelerator is mainly formed by connecting a plurality of linear induction accelerating cavities (induction cavities for short) in series. The induction cavity is typically inductively isolated by a non-linear magnetic core loaded in the ferromagnetic chamber of an annular stainless steel cavity, providing a time varying field inside the vacuum acceleration gap without external potential summation. The product of the magnetic induction increment of the magnetic core and the cross-sectional area of the magnetic core (called volt-seconds) represents the capacity of the induction cavity to generate induction pulses with certain amplitude and width.

The magnetic material in the induction cavity of the linear induction accelerator is typically a ferrite or amorphous core. Because the magnetic induction increment of amorphous magnetic ribbon (about 3T) is much greater than ferrite (about 0.7T), with the rapid development of amorphous magnetic ribbon manufacturing technology, current linac cavities tend to use amorphous cores, especially in situations where long-pulse, multi-pulse linacs, etc. require cores to provide more volt-seconds, such as the long-pulse (-2 mus) linac dart-II cavity in the united states (fig. 1). Even considering the encapsulation of the amorphous magnetic strip, the increment of the magnetic induction of the amorphous magnetic ring as a finished product is more than 1.4T, the price is basically consistent with the ferrite with the same size, and therefore, compared with the ferrite core, the amorphous core is beneficial to greatly reducing the cross-sectional area of the induction cavity in terms of the capability of providing the voltage seconds required by the induction voltage with certain amplitude and width.

However, the amorphous magnetic core induction cavity suitable for the existing engineering has two main weaknesses at present: firstly, the problem of high-voltage withstand voltage is solved; one is the problem of large increases in beam tube radius to meet the design requirements for lateral coupling impedance.

The amorphous magnetic material (also called metallic glass) used in the amorphous magnetic core induction cavity is a good electric conductor, the skin depth is only a few tenths of microns, and when the amorphous magnetic core induction cavity is used, a micron-sized thin strip is required to be manufactured, wrapped by an insulating material (or a coating), and wound into a ring shape. Besides the interlayer insulation of all the amorphous magnetic cores and the insulation at the inner and outer diameters of the amorphous magnetic cores, the insulation of the amorphous magnetic cores at the high-voltage feed-in part needs to be considered. Due to the design defect that the amorphous magnetic core of the amorphous induction cavity is too close to the high-voltage feeding plate, large-area breakdown occurs in the induction cavity of the amorphous magnetic core originally designed in the American DARHT-II during high-voltage debugging. After a series of complicated processes such as accelerated cavity integral cutting, lengthening and packaging are adopted to increase The distance between The high-voltage feed plate and The amorphous magnetic core and insulating spokes are used (refer to The literature, "Mechanical engineering extensions to The DARHT-II indication cells", j.barrazat, t.ilg, k.nielsen, et.al., The 15th IEEE International Pulsed Power Conference,2005), The DARHT-II finally completes debugging after a delay of seven years. The insulating spokes also waste DARHT-II sensing chamber ferromagnetic chamber space.

In addition, from the perspective of stable transmission of strong current beams over long distances, the structural design of the sensing cavity needs to consider the problem of Beam Break-UP instability (BBU) suppression, and how to control the lateral coupling impedance of the acceleration cavity within a required range is an important consideration. The lateral coupling impedance is proportional to the gap width and inversely proportional to the square of the pipe radius. The amorphous magnetic material is similar to metal and can strongly reflect electromagnetic waves, so that the transverse coupling impedance of the amorphous magnetic core induction cavity is high, in order to design the transverse coupling impedance of the amorphous magnetic core induction cavity to an acceptable degree, the radius of a beam pipeline of the metal glass induction cavity needs to be greatly increased, and thus, the inner radius and the outer radius of the magnetic core need to be increased, and the reduction of the using amount and the cost of the magnetic core caused by the high magnetic induction intensity increment of the amorphous material is offset to a certain degree. For example, in the American DARHT-II long pulse linear induction accelerator, the acceleration gap width of an amorphous magnetic core induction cavity is designed to be 25mm, the radius of the beam pipelines of the first 8 induction cavities behind an injector is designed to be 178mm, and the radius of the beam pipelines of the rest induction cavities also reaches 127 mm; in contrast, the typical short pulse linear induction accelerators such as DARHT-I in the United states, AIRIX in France, etc. have ferrite sensing cavities with an acceleration gap width of 19mm and a beam tube radius of 74 mm.

As described above, the conventional amorphous magnetic core sensing cavity has a great advantage in that the magnetic core provides enough volt-seconds due to the high increment of the magnetic induction intensity of the amorphous magnetic material, and can be used for short pulses, long pulses, multi-pulses and other situations requiring more volt-seconds, however, the amorphous magnetic core sensing cavity has the problems of potential pressure resistance hazard due to the proximity of the amorphous magnetic core and the high-voltage feed-in plate, ferromagnetic room space waste caused by insulating spokes, and great increase in the usage amount and cost of the magnetic core due to the increase of the radius of the beam conduit for reducing the transverse coupling impedance.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the prior art, and the invention aims to provide a novel linear induction accelerating cavity structure to solve the problems of transverse coupling impedance and voltage resistance of an amorphous magnetic core induction cavity.

The invention is realized by the following technical scheme: the utility model provides a new cavity structure is accelerated in sharp response, includes the ferromagnetic room, is equipped with the magnetic core group in the ferromagnetic room, and the magnetic core group includes ferrite core and amorphous magnetic core.

Further, the ferrite core is positioned between the amorphous core and the acceleration gap.

Further, the ferrite core is positioned between the amorphous core and the high-voltage feeding plate forming the accelerating gap.

Furthermore, the ferrite magnetic core is provided with a block.

Further, the outer shell, the short circuit disc I, the middle shell and the high-voltage feed-in plate form a ferromagnetic chamber.

Furthermore, the device also comprises a coil chamber, and a coil group is arranged in the coil chamber.

Further, the coil assembly comprises a helical coil and a correction coil.

Further, the short circuit disc I, the middle shell, the inner shell and the high-voltage feed-in plate form a coil chamber.

Further, the high voltage feed plate and the short circuit disc II form an acceleration gap.

Furthermore, an insulating ring is arranged in the accelerating gap.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the invention relates to a novel linear induction accelerating cavity structure.A ferrite magnetic material is used in a ferromagnetic chamber close to a high-voltage feed plate, and due to the wave-absorbing property of the ferrite magnetic material, when a ferrite is placed on the surface of an amorphous magnetic core, the transverse impedance is greatly reduced, and the transverse coupling impedance of the amorphous magnetic core induction cavity is reduced by adopting a mode of increasing the radius of a beam pipeline to meet the transportation requirement of a strong beam like a conventional amorphous magnetic core induction cavity. Compared with the existing amorphous magnetic core induction cavity, the induction cavity has a more compact structure.

2. The invention relates to a novel linear induction accelerating cavity structure, wherein the volt-seconds needed for supporting pulse voltage with certain amplitude and pulse width are mainly provided by an amorphous magnetic core in a ferromagnetic chamber, a ferrite magnetic material is used in the ferromagnetic chamber close to a high-voltage feeding plate, and the ferrite magnetic material is similar to an insulating material and separates the amorphous magnetic core from the high-voltage feeding plate, so that the voltage resistance of the amorphous magnetic core induction accelerating cavity is greatly improved. Compared with the existing amorphous magnetic core induction cavity, the induction cavity structure has stronger pressure resistance and more reliable operation.

3. The novel linear induction accelerating cavity structure is compact and reliable, and can be used for short pulses, long pulses, multi-pulses and other situations requiring more volt-seconds. Compared with the existing induction cavity, the induction cavity can reduce the using amount of the magnetic core, improve the acceleration gradient, reduce the length of the accelerator, facilitate the transmission of the strong flux beam and greatly reduce the manufacturing cost of the accelerator.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a schematic diagram of an amorphous magnetic core induction cavity structure.

FIG. 2 is a schematic view of the structure of the present invention.

Reference numbers and corresponding part names in the drawings: 1-insulating spoke, 2-ferrite core, 3-amorphous core, 4-outer shell, 5-short circuit disc I, 6-middle shell, 7-coil group, 8-inner shell, 9-high voltage feed plate, 10-insulating ring, 11-short circuit disc II.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

Examples

As shown in fig. 2, the new linear induction accelerating cavity structure of the invention comprises an outer shell 4 made of magnetic tiny cylindrical stainless steel, an annular short circuit disk I5, a cylindrical middle shell 6, a cylindrical inner shell 8, an annular high voltage feed plate 9, an annular insulating ring 10 and an annular short circuit disk II 11.

The outer housing 4, a part of the short circuit disc I5, the middle shell 6 and a part of the high voltage feed plate 9 form a ferromagnetic chamber, a part of the short circuit disc I5, the middle shell 6, the inner housing 8 and a part of the high voltage feed plate 9 form a coil chamber, and the high voltage feed plate 9 and the short circuit disc II11 form an acceleration gap.

The ferromagnetic chamber is internally provided with a magnetic core group which comprises a ferrite magnetic core 2 and an amorphous magnetic core 3. The ferrite magnetic core 2 is arranged one block, and the ferrite magnetic core 2 is positioned between the amorphous magnetic core 3 and the high-voltage feed-in plate 9, is used for absorbing waves and improving the voltage-resisting capability of the induction cavity, and can provide certain volt-seconds. The number of amorphous cores may be determined according to the desired number of volt-seconds.

The coil chamber is internally provided with a coil group, and the coil group comprises a helical tube coil and a correction coil. An insulating ring 10 is provided in the acceleration gap for supporting the acceleration voltage applied therebetween and separating the transformer oil in the region of the ferromagnetic chamber and the vacuum region of the acceleration duct.

In one embodiment, the new linear induction acceleration chamber structure for the strong flux stream transmission is as follows: besides different magnetic cores used in the ferromagnetic chamber, the inductive cavities with the same structure are used for measuring the transverse coupling impedance under different magnetic cores. The ferrite core is a domestic NZ ferrite core, the outer diameter is 508mm, the inner diameter is 254mm, the thickness is 25mm, Bs is more than or equal to 0.38T, and Br is more than or equal to 0.29T; the amorphous magnetic core is a domestic fast pulse large-size amorphous magnetic core, and is packaged with the outer diameter of 497mm, the inner diameter of 266mm and the thickness of 27 mm. When the domestic NZ ferrite magnetic cores are all used, the frequency corresponding to the TM110 mode is 450MHz, and the transverse coupling impedance is 99.3 omega/m; when the domestic fast pulse large-size amorphous magnetic cores with corresponding sizes are all used, the frequency corresponding to the TM110 mode is 539MHz, and the transverse coupling impedance is 175 omega/m; when the magnetic core combination of 'amorphous magnetic core +1 ferrite' is used, the frequency corresponding to TM110 mode is 437MHz, and the transverse coupling impedance is 108 Ω/m. Compared with the case of completely using a ferrite magnetic core, when the amorphous magnetic core is completely used, the transverse coupling resistance of the induction cavity is 76 percent higher; compared with the case of completely using ferrite cores, the magnetic core combination of the amorphous magnetic core and 1 ferrite has the advantages that the transverse coupling impedance of the induction cavity is only 8% larger, the situation is basically consistent with the situation of completely using ferrite cores, and the ferrite cores play a very excellent wave absorbing effect in the magnetic core combination of the amorphous magnetic core and 1 ferrite.

In another embodiment, high voltage tests were performed under different conditions using the same configuration of the induction chamber, except that the cores used in the ferromagnetic chamber were different. The ferrite core is a domestic NZ ferrite core, the outer diameter is 508mm, the inner diameter is 254mm, the thickness is 25mm, Bs is more than or equal to 0.4T, and Br is more than or equal to 0.3T; the amorphous magnetic core is a domestic fast pulse large-size amorphous magnetic core, and is packaged with the outer diameter of 497mm, the inner diameter of 266mm and the thickness of 27 mm. Under the two conditions of using 11 domestic NZ ferrites and using 6 amorphous magnetic cores and 1 ferrite, 250kV high-voltage square wave pulse is obtained, the volt-second number and the voltage resistance of the amorphous magnetic cores meet the requirements, and the insulating spokes 1 do not need to be provided for high-voltage protection. In addition, high-voltage saturation experiments of the magnetic cores prove that the volt-second number provided by 1 packaged amorphous magnetic core is approximately equal to the volt-second number provided by 2 ferrite magnetic cores, the increased ferrite magnetic cores relative to the insulating spokes can also provide the volt-second number for the acceleration cavity, the use amount of the magnetic cores is further reduced, and the overall structure of the acceleration cavity is reduced.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.