阅读说明：本技术 一种产生高品质电子束的往返式同轴腔电子加速器 (Reciprocating type coaxial cavity electron accelerator for generating high-quality electron beam ) 是由 赵全堂 张子民 李中平 曹树春 刘铭 申晓康 宗阳 李佳 于 2020-12-30 设计创作，主要内容包括：本发明涉及一种产生高品质电子束的往返式同轴腔电子加速器,包括电子枪、加速腔和高频功率源,还包括设置在加速腔外部的束流偏转引导系统,由束流偏转引导系统引导电子多次加速。本发明能获得束流能量均匀性好,降低束流损失,同时提高了往返式同轴腔电子加速器产生的束流品质。本发明可以广泛在加速器技术领域中应用。(The invention relates to a reciprocating type coaxial cavity electron accelerator for generating high-quality electron beams, which comprises an electron gun, an accelerating cavity, a high-frequency power source and a beam deflection guide system arranged outside the accelerating cavity, wherein the beam deflection guide system guides electrons to accelerate for multiple times. The invention can obtain good beam energy uniformity, reduce beam loss and improve the beam quality generated by the reciprocating type coaxial cavity electron accelerator. The invention can be widely applied to the technical field of accelerators.)

1. A reciprocating coaxial cavity electron accelerator for generating high-quality electron beams comprises an electron gun, an accelerating cavity and a high-frequency power source, and is characterized in that: the electron beam accelerator also comprises a beam deflection guide system arranged outside the acceleration cavity, and electrons are guided by the beam deflection guide system to accelerate for multiple times.

2. The accelerator of claim 1, wherein: the beam deflection guiding system comprises a plurality of QFs and a plurality of BDs, wherein the QFs are permanent magnetic quadrupole magnet structures focused in the horizontal direction, and the BDs are a plurality of composite permanent magnets which simultaneously have dipolar magnetic fields deflected in the horizontal direction and quadrupole magnetic fields defocused in the horizontal direction; each QF and each BD are connected together to form a QF-BD module, and a plurality of QF-BD modules form a beam transmission mode which deflects transversely and focuses-defocuses horizontally at the same time.

3. The accelerator of claim 2, wherein: and the QF and the BD are spliced and assembled together through permanent magnets by adopting a padding method.

4. The accelerator of claim 2, wherein: and setting the number of the QF-BD modules to form different beam transmission tracks.

Technical Field

The invention relates to the technical field of accelerators, in particular to a reciprocating type coaxial cavity electron accelerator for generating high-quality electron beams.

Background

The reciprocating coaxial cavity electron accelerator consists of an electron gun, an accelerating cavity, a high-frequency power source, a rotary magnet and the like. The accelerating cavity is a coaxial resonant cavity, after an electron beam from the electron gun enters the accelerating cavity at a proper phase and is accelerated, the high-frequency electric field is reversed during the period that the electron beam passes through a field-free area of the inner cylinder, so that the electron beam still receives the action of the accelerating field when entering the other half of the accelerating cavity. After the electron beam comes out of the accelerating cavity, the electron beam is turned outside the cavity by the rotary magnet, the rotary magnet is used for twisting the electron flying out of the accelerating cavity, the flight time of the electron beam is properly designed, and the electron beam passes through the accelerating cavity again to be accelerated again, so that the energy is improved. The existing accelerators of the same type all adopt window frame type or H type, C type monoblock electromagnet or permanent magnet as rotary magnet, and the basic schematic diagram of the working principle is shown in figure 1.

The conventional electromagnets are used as rotary magnets in the prior accelerators of the same type, the conventional electromagnets need direct-current power supply for excitation, and magnet coils need water for cooling, so that the manufacturing cost and the running cost of the whole accelerator are higher. In addition, a permanent magnet is also used as the rotary magnet. The design scheme of using a complete dipolar magnet as a rotary magnet has many limitations. The rotating beam current is not of a dispersion eliminating structure, the parameters of the rotating beam current are poor, the transverse size of the beam current is overlarge, the subsequent acceleration process is not facilitated, and the energy uniformity of the generated beam current is poor. The transverse focusing is weak focusing, the current control capability to the beam is poor, the y direction is realized by a field caused by the included angle between the dipolar iron pole face and the beam, and the x direction is realized by the focusing effect when the deflection is more than 180 degrees. Therefore, the beam spot size of some parts is too large, which easily causes beam loss, and the beam quality is poor due to insufficient lateral control of the beam.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a reciprocating type coaxial cavity electron accelerator for generating high quality electron beams, which has good uniformity of beam energy, reduces beam loss, and simultaneously improves the beam quality generated by the reciprocating type coaxial cavity electron accelerator.

In order to achieve the purpose, the invention adopts the following technical scheme: a reciprocating type coaxial cavity electron accelerator for generating high-quality electron beams comprises an electron gun, an accelerating cavity, a high-frequency power source and a beam deflection guide system arranged outside the accelerating cavity, wherein electrons are guided by the beam deflection guide system to accelerate for multiple times.

Further, the beam deflection guiding system comprises a plurality of QFs and BDs, wherein the QFs are permanent magnetic quadrupole magnet structures focused in the horizontal direction, and the BDs are a plurality of composite permanent magnets which simultaneously have dipolar magnetic fields deflected in the horizontal direction and quadrupole magnetic fields defocused in the horizontal direction; each QF and each BD are connected together to form a QF-BD module, and a plurality of QF-BD modules form a beam transmission mode which deflects transversely and focuses-defocuses horizontally at the same time.

Furthermore, the QF and the BD are spliced and assembled together through permanent magnets by a padding method.

Further, the number of the QF-BD modules is set to form different beam transmission tracks.

Due to the adoption of the technical scheme, the invention has the following advantages: 1. the reciprocating type coaxial cavity electron accelerator is realized by guiding electrons to accelerate for multiple times by utilizing the combined structure type permanent magnet deflection system, and because the permanent magnet is adopted to guide the electron beams to pass through the accelerating cavity for multiple times, the power consumption and the cooling water of the electromagnet are saved, and the manufacturing cost and the running cost are saved. 2. The invention realizes the requirements of precise control of beam transmission guidance, matching of subsequent acceleration and the like through the combined structure type permanent magnet achromatic deflection system, ensures that the obtained beam energy has good uniformity, reduces beam loss, improves the beam quality generated by the reciprocating type coaxial cavity electron accelerator, and widens the application field of the accelerator. 3. The present invention provides a new reciprocating type coaxial cavity electron accelerator which utilizes the deflection of a permanent magnet with a combined structure to guide electrons to accelerate for a plurality of times. The permanent magnet with the combined structure is used for replacing the conventional magnet, so that the obtained beam energy is good in uniformity, the beam loss is reduced, and the beam quality generated by the conventional reciprocating type coaxial cavity electron accelerator is improved. 4. The deflection guide system adopted by the invention has flexible structural design, stronger transverse focusing on beam current and more design freedom, can meet various requirements, is not only used for industrial irradiation processing types, but also can meet the requirements of accelerators for scientific research, such as electron cooling of high-energy ion beams, free electron laser with high average power and the like, and widens the application field of reciprocating type coaxial cavity electron accelerators.

Drawings

FIG. 1 is a schematic diagram of the operation principle of a reciprocating coaxial cavity electron accelerator in the prior art;

FIG. 2a is a diagram illustrating a structure of a horizontally focused permanent magnet quad-polar QF according to an embodiment of the present invention;

FIG. 2b is a schematic structural diagram of a BD having a horizontally deflected dipolar magnetic field and a horizontally defocused quadrupole magnetic field in accordance with an embodiment of the present invention;

fig. 3 is a schematic diagram of the design of a combined achromatic deflection magnet system for a reciprocating coaxial cavity electron accelerator according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "inside", "outside", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

As shown in fig. 2a to 3, the present invention provides a reciprocating type coaxial cavity electron accelerator for generating high quality electron beams, which comprises an electron gun, an acceleration cavity and a high frequency power source in the prior art, and is distinguished by further comprising a beam deflection guiding system arranged outside the acceleration cavity, wherein electrons are guided by the beam deflection guiding system to accelerate for multiple times. The beam deflection guiding system includes a plurality of horizontal focusing permanent magnetic Quadrupole (QF) structures and a plurality of combined type permanent magnets (BD) having both horizontal deflecting dipole magnetic field and horizontal defocusing Quadrupole magnetic field, as shown in fig. 2a and 2 b. Each QF and each BD are connected together to form a QF-BD module, a plurality of QF-BD modules form a beam transmission mode which deflects transversely and focuses and defocuses horizontally at the same time, and the plurality of QF-BD modules realize the preset required distribution of two-pole and four-pole magnetic fields.

In the present embodiment, five sets of QF-BD modules (as shown in fig. 3) are preferred, but not limited thereto.

In a preferred embodiment, the QF and the BD are spliced and assembled together through permanent magnets by a padding method.

In a preferred embodiment, different beam transmission trajectories are formed according to different number settings of the QF-BD modules.

In summary, when the invention is used, according to the requirement of beam synchronization during the next acceleration after each acceleration, namely the requirement of the transmission distance of the deflection part, the QF-BD modules with different numbers can be adopted to realize the proper beam transmission track, and the design structure is compact. The guide system is adopted to guide the reciprocating type coaxial cavity electron accelerator for accelerating electrons for multiple times, the requirements of precise control, matching of subsequent acceleration and the like are met, and finally high-quality electron beams are obtained.

The above embodiments are only for illustrating the present invention, and the structure, size, arrangement position and shape of each component can be changed, and on the basis of the technical scheme of the present invention, the improvement and equivalent transformation of the individual components according to the principle of the present invention should not be excluded from the protection scope of the present invention.