阅读说明：本技术 一种基于固体传导冷却的无液氦射频超导加速模组 (Liquid helium-free radio frequency superconducting acceleration module based on solid conduction cooling ) 是由 杨自钦 何源 蒋天才 白峰 王玥 刘鲁北 李春龙 张军辉 张生虎 于 2021-08-05 设计创作，主要内容包括：本发明涉及一种基于固体传导冷却的无液氦射频超导加速模组,包括：超导腔,被配置成给带电粒子束提供能量；低温单元,被配置成向超导腔提供所需的低温环境；真空单元,与超导腔连接,真空单元被配置成向超导腔提供运行所需的腔体真空环境与夹层真空环境；耦合器,与超导腔的耦合口连接,耦合器被配置成向超导腔馈入射频功率。本发明摆脱了传统超导腔必须浸泡在液氦里冷却的工作方式,一方面其布局紧凑,布置简单,维护方便,维护周期长,应用简单,能够显著降低射频超导技术在小规模应用的难度和成本；另一方面,其造价远低于当前的液氦浸泡式射频超导加速单元,非常适合射频超导技术的小型化、产业化应用。(The invention relates to a liquid helium-free radio frequency superconducting acceleration module based on solid conduction cooling, which comprises: a superconducting cavity configured to provide energy to a charged particle beam; a cryogenic unit configured to provide a desired cryogenic environment to the superconducting cavity; the vacuum unit is connected with the superconducting cavity and is configured to provide a cavity vacuum environment and an interlayer vacuum environment required by operation for the superconducting cavity; and the coupler is connected with the coupling port of the superconducting cavity and is configured to feed radio frequency power into the superconducting cavity. The invention gets rid of the working mode that the traditional superconducting cavity is cooled by soaking in liquid helium, on one hand, the layout is compact, the arrangement is simple, the maintenance is convenient, the maintenance period is long, the application is simple, and the difficulty and the cost of the radio frequency superconducting technology in small-scale application can be obviously reduced; on the other hand, the manufacturing cost is far lower than that of the current liquid helium soaking type radio frequency superconducting accelerating unit, and the liquid helium soaking type radio frequency superconducting accelerating unit is very suitable for miniaturization and industrial application of a radio frequency superconducting technology.)

1. A no liquid helium radio frequency superconducting accelerates module based on solid conduction cooling, its characterized in that includes:

a superconducting cavity (1) configured to provide energy to a charged particle beam;

a cryogenic unit (2) configured to provide a required cryogenic environment to the superconducting cavity (1);

a vacuum unit (3) connected to the superconducting cavity (1), the vacuum unit (3) being configured to provide a cavity vacuum environment and an interlayer vacuum environment required for operation to the superconducting cavity (1);

a coupler (4) connected to a coupling port of the superconducting cavity (1), the coupler (4) being configured to feed radio frequency power into the superconducting cavity (1).

2. The liquid-helium-free radio-frequency superconducting acceleration module according to claim 1, characterized in that the cryogenic unit (2) comprises:

a cold shield (2-1) housed outside the superconducting cavity (1), the cold shield (2-1) being configured to reduce static heat loss of the superconducting cavity (1);

a magnetic shielding layer arranged in the space between the cold shield (2-1) and the superconducting cavity (1), said magnetic shielding layer being configured to shield the earth's ambient magnetic field, reducing the magnetic flux capture of the superconducting cavity (1);

the multiple groups of cold guide blocks (2-2) are arranged in the heating area of the superconducting cavity (1), and the inner surface of each cold guide block (2-2) is attached to the outer surface of the superconducting cavity (1);

the secondary cold plates (2-3) are arranged above the cold guide blocks (2-2), and one sides of the secondary cold plates (2-3) are respectively connected with the three groups of cold guide blocks (2-2) through flexible cold chains (2-4);

and at least one refrigerating machine (2-5) is arranged above the secondary cold plate (2-3), and a secondary cold head (2-6) of the refrigerating machine (2-5) is connected with the other side of the secondary cold plate (2-3) through a flexible cold chain (2-4).

3. The liquid helium-free radio frequency superconducting acceleration module according to claim 2, characterized in that the cold guide blocks (2-2) are in a half-and-half hoop form, and the half-and-half hoops of the cold guide blocks (2-2) are fastened and connected through screws and nuts;

meanwhile, indium sheets are uniformly arranged on the contact interface of the cold guide block (2-2) and the superconducting cavity (1) and the connection part of the half-and-half hoops;

in addition, the screw is a 316L stainless steel screw, and the nut is a silicon bronze nut; the fastening torque of the screw and the nut is 115N.m, and the thermal resistance of the fastening connection part is ensured to be lower than 1 x 10^-4Km²/W。

4. The liquid-helium-free radio frequency superconducting acceleration module according to claim 2, characterized in that temperature sensors are arranged on the outer surface of the heating region of the superconducting cavity (1), the cold guide blocks (2-2), the secondary cold plates (2-3) and the secondary cold heads (2-6) for monitoring the temperature change of the superconducting cavity (1);

meanwhile, a high-precision heater is arranged on the secondary cold head (2-6) and is used for being matched with a temperature controller and a temperature sensor, so that the condition that the cooling rate is stable between 30K and 15K and is continuously adjustable between 1min/K and 5min/K is realized, and the temperature gradient of the superconducting cavity (1) in the axial direction is ensured to be less than or equal to 0.025K/cm;

a fluxgate probe is arranged on the outer surface of the superconducting cavity (1), and the fluxgate probe is required to be capable of accurately measuring the magnetic field intensity less than or equal to 10mGs for residual magnetism measurement and monitoring.

5. The liquid-helium-free radio-frequency superconducting acceleration module according to claim 4, characterized in that the vacuum unit (3) comprises:

a vacuum enclosure (3-1) arranged outside the cold shield (2-1), the vacuum enclosure (3-1) being configured to form a sandwich vacuum environment for reducing static heat loss between the vacuum enclosure (3-1) and the superconducting cavity (1);

one end of each of the two groups of vacuum pipelines (3-2) is respectively connected with the two flow pipelines of the superconducting cavity (1) through a vacuum angle valve (3-3), and the other end of each of the two groups of vacuum pipelines (3-2) penetrates out of the vacuum cover (3-1) and then is connected with a vacuum pump set, so that a cavity vacuum environment for accelerating charged particles is formed in a superconducting cavity-pipeline system formed by the superconducting cavity (1) and the vacuum pipelines (3-2).

6. The liquid helium-free radio frequency superconducting acceleration module according to claim 5, characterized in that the cavity vacuum environment requires a leak rate at room temperature of not more than 5e-10mbarL/S, and the cavity vacuum environment requires a vacuum degree at room temperature of not more than 5e-5 Pa;

the vacuum degree of the interlayer is required to be less than or equal to 5e-8mbarL/S at normal temperature, and the vacuum degree of the interlayer is required to be less than or equal to 5e-3Pa at normal temperature.

7. The liquid helium-free radio frequency superconducting acceleration module according to claim 5, characterized in that the vacuum hood (3-1) is made of stainless steel, and the inner surface and the outer surface are polished; the top of the vacuum cover (3-1) is provided with a butt joint of the refrigerator (2-5), the side is provided with a butt joint of the vacuum pipeline (3-2), and the bottom is provided with a butt joint of the coupler (4); a temperature sensor wall penetrating piece (3-4) is reserved on the vacuum cover (3-1) and is used for butt joint of a data line of the temperature sensor; a magnetic probe sensor wall penetrating piece (3-5) is reserved on the vacuum cover (3-1) and is used for butt joint of data lines of the fluxgate probe; and a backfill port is reserved in the vacuum cover (3-1) and is used for high-purity nitrogen inflation recovery vacuum and pipeline cleaning.

8. The liquid-helium-free radio frequency superconducting acceleration module according to claim 5, characterized by further comprising a shock absorber (5) disposed on top of the vacuum enclosure (3-1), the refrigerator (2-5) being disposed on the shock absorber (5);

meanwhile, the vibration of the refrigerating machine (2-5) is effectively prevented from being transmitted to the superconducting cavity (1) through a flexible cold chain (2-4) between a secondary cold head (2-6) of the refrigerating machine (2-5) and the superconducting cavity (1).

9. Liquid-helium-free radio-frequency superconducting acceleration module according to claim 5, characterized in that the superconducting cavity (1) is supported inside the vacuum enclosure (3-1) by a support structure (6) made of non-magnetic material, and a fine tuning rod is arranged on the support structure (6).

10. The liquid-helium-free radio frequency superconducting acceleration module according to any one of claims 1 to 9, wherein the inner surface of the superconducting cavity (1) is formed with a thin film of high temperature superconducting material, which is a material with a superconducting transition temperature higher than 15K at zero magnetic field and a superheated magnetic field higher than 150mT at 4K.

Technical Field

The invention relates to a superconducting accelerator, in particular to a liquid helium-free radio frequency superconducting acceleration module based on solid conduction cooling, and belongs to the technical field of superconduction.

Background

The low-energy high-current high-power electron linear accelerator provides an important research platform for electron beam irradiation, X rays, terahertz coherent light sources, photon sources and the like. Especially, along with social development, electron beam irradiation has important industrial application potential in treating environmental pollution problems such as waste gas, waste water and the like. Due to the extremely low surface resistance in a superconducting state, the superconducting cavity allows the design of a large beam aperture, the interaction of the beam cavity is remarkably reduced, the superconducting cavity can operate in a high duty ratio mode or even a continuous wave mode, and the superconducting cavity has the advantage of being extremely thick in the aspect of accelerating a high-current particle beam. The superconducting accelerator based on the niobium-based superconducting cavity is cooled by liquid helium soaked between 2K and 4K, needs a large-scale low-temperature refrigeration station, a complex thermostat system and a professional low-temperature refrigeration maintenance team, and is a main obstacle for popularization and application of a radio frequency superconducting technology.

At present, the radio frequency performance of a high-temperature superconducting material superconducting cavity with the superconducting transition temperature of more than or equal to 15K under the state of 4.2K and even cold helium can reach the level of a niobium-based superconducting cavity under 2K. Meanwhile, the technology of the industrial refrigerator is rapidly developed in recent years, the refrigerating power of 2W can be achieved at the low temperature of 4.2K, and the average maintenance period of the domestic industrial refrigerator is up to 18 months at present. The high-temperature superconducting material superconducting cavity electron accelerator based on the commercial refrigerator solid conduction cooling does not need liquid helium cooling, a liquid helium soaking cooling thermostat with a complex structure and a liquid helium low-temperature station with high manufacturing cost and large occupied area are omitted, the structure is simple, the scale is small, the operation and the maintenance are convenient, the difficulty and the cost of the small-scale application of the radio frequency superconducting technology can be obviously reduced, and the high-temperature superconducting material superconducting cavity electron accelerator is very suitable for the miniaturization and the industrialization application of the radio frequency superconducting technology.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a liquid-helium-free radio frequency superconducting acceleration module based on solid conduction cooling, so as to get rid of the working mode that the conventional superconducting cavity must be immersed in liquid helium for cooling, and reduce the difficulty in applying the radio frequency superconducting technology.

In order to achieve the purpose, the invention adopts the following technical scheme: a liquid helium-free radio frequency superconducting acceleration module based on solid conduction cooling comprises: a superconducting cavity configured to provide energy to a charged particle beam; a cryogenic unit configured to provide a desired cryogenic environment to the superconducting cavity; a vacuum unit connected to the superconducting cavity, the vacuum unit configured to provide a cavity vacuum environment and an interlayer vacuum environment required for operation to the superconducting cavity; a coupler connected to a coupling port of the superconducting cavity, the coupler configured to feed radio frequency power into the superconducting cavity.

Preferably, the low-temperature unit includes: a cold shield disposed outside the superconducting cavity, the cold shield configured to reduce static heat loss from the superconducting cavity; a magnetic shielding layer disposed in a space between the cold shield and the superconducting cavity, the magnetic shielding layer configured to shield an earth ambient magnetic field, reducing magnetic flux capture by the superconducting cavity; the three groups of cold guide blocks are respectively arranged in the equator region and the beam pipeline regions on the two sides of the superconducting cavity along the circumferential direction, and the inner surfaces of the cold guide blocks are attached to the equator region and the outer surfaces of the beam pipeline regions of the superconducting cavity; the secondary cold plate is arranged above the cold guide blocks, and one side of the secondary cold plate is respectively connected with the three groups of cold guide blocks through flexible cold chains; and at least one refrigerating machine is arranged above the secondary cold plate, and a secondary cold head of the refrigerating machine is connected with the other side of the secondary cold plate through a flexible cold chain.

The liquid helium-free radio frequency superconducting accelerating module is preferably characterized in that the cold guide block is in a half-and-half hoop form, and the half-and-half hoops of the cold guide block are all screwed and screwed through screws and nutsFastening and connecting; meanwhile, indium sheets are uniformly arranged on the contact interface of the cold guide block and the superconducting cavity and the connection part of the half-and-half hoops; in addition, the screw is a 316L stainless steel screw, and the nut is a silicon bronze nut; the fastening torque of the screw and the nut is 115N.m, and the thermal resistance of the fastening connection part is ensured to be lower than 1 x 10^-4Km²/W。

Preferably, temperature sensors are arranged on the outer surface of a heating area of the superconducting cavity, the cold conducting block, the secondary cold plate and the secondary cold head and are used for monitoring the temperature change of the superconducting cavity; meanwhile, a high-precision heater is arranged on the secondary cold head and is used for being matched with a temperature controller and a temperature sensor, so that the conditions that the cooling rate is stable between 30K and 15K and is continuously adjustable between 1min/K and 5min/K are realized, and the temperature gradient of the superconducting cavity in the axial direction is ensured to be less than or equal to 0.025K/cm;

and a fluxgate probe is arranged on the outer surface of the superconducting cavity, and the fluxgate probe is required to be capable of accurately measuring the magnetic field intensity less than or equal to 10mGs for residual magnetism measurement and monitoring.

Preferably, the vacuum unit includes: a vacuum enclosure disposed outside the cold shield, the vacuum enclosure configured to form an interlayer vacuum environment between the vacuum enclosure and the superconducting cavity for reducing static heat loss; and one ends of the two groups of vacuum pipelines are respectively connected with the two flow pipelines of the superconducting cavity through vacuum angle valves, and the other ends of the two groups of vacuum pipelines penetrate out of the vacuum cover and are connected with a vacuum pump set so as to form a cavity vacuum environment for accelerating charged particles in a superconducting cavity-pipeline system consisting of the superconducting cavity and the coupler.

Preferably, the leakage rate of the liquid helium-free radio frequency superconducting acceleration module at normal temperature is not more than 5e-10mbarL/S in the cavity vacuum environment, and the vacuum degree of the cavity vacuum environment is not more than 5e-5Pa at normal temperature; the vacuum degree of the interlayer is required to be less than or equal to 5e-8mbarL/S at normal temperature, and the vacuum degree of the interlayer is required to be less than or equal to 5e-3Pa at normal temperature.

Preferably, the vacuum cover is made of stainless steel, and the inner surface and the outer surface of the vacuum cover are polished; the top of the vacuum cover is provided with a butt joint port of the refrigerator, the side of the vacuum cover is provided with a butt joint port of the vacuum pipeline, and the bottom of the vacuum cover is provided with a butt joint port of the coupler; a temperature sensor wall penetrating piece is reserved on the vacuum cover and is used for butt joint of data lines of the temperature sensor; a magnetic probe sensor wall penetrating piece is reserved on the vacuum cover and is used for butt joint of data lines of the fluxgate probe; and a backfill port is reserved in the vacuum cover and used for high-purity nitrogen inflation vacuum recovery and pipeline cleaning.

The liquid helium-free radio frequency superconducting acceleration module preferably further comprises a shock absorber arranged at the top of the vacuum cover, and the refrigerator is arranged on the shock absorber; meanwhile, the vibration of the refrigerator is effectively prevented from being transmitted to the superconducting cavity through a flexible cold chain between a secondary cold head of the refrigerator and the superconducting cavity.

Preferably, the superconducting cavity is supported in the vacuum cover through a supporting structure made of a non-magnetic material, and the supporting structure is provided with a fine adjustment rod.

Preferably, a film of a high-temperature superconducting material is formed on the inner surface of the superconducting cavity, and the high-temperature superconducting material is a material with a superconducting transition temperature higher than 15K at zero magnetic field and a superheated magnetic field higher than 150mT at 4K.

Due to the adoption of the technical scheme, the invention has the following advantages:

the invention is based on a commercial refrigerator, cools the superconducting cavity in a solid conduction mode, so that the superconducting cavity stably runs at a low temperature, gets rid of the cooling mode that the radio-frequency superconducting accelerating cavity can only be soaked in liquid helium at present, saves a liquid helium soaking cooling thermostat with a complex structure and a liquid helium low-temperature station with high manufacturing cost and large occupied area, has compact layout, simple arrangement, convenient maintenance, long maintenance period and simple application on one hand, and can obviously reduce the difficulty and the cost of the radio-frequency superconducting technology in small-scale application; on the other hand, the manufacturing cost is far lower than that of the current liquid helium soaking type radio frequency superconducting accelerating unit, and the liquid helium soaking type radio frequency superconducting accelerating unit is very suitable for miniaturization and industrial application of a radio frequency superconducting technology.

Drawings

Fig. 1 is a schematic diagram illustrating an overall structure of a liquid-helium-free rf superconducting acceleration module according to an embodiment of the present invention;

fig. 2 is an axial cross-sectional view of the liquid-helium-free rf superconducting acceleration module according to the embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted 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, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the system or element referred to 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. Furthermore, the terms "first," "second," and the like, are used to define elements only for convenience in distinguishing between the elements, and unless otherwise stated have no special meaning and are not to be construed as indicating or implying any relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The invention provides a solid conduction cooling-based liquid helium-free radio frequency superconducting acceleration module, which comprises: a superconducting cavity configured to provide energy to a charged particle beam; a cryogenic unit configured to provide a desired cryogenic environment to the superconducting cavity; the vacuum unit is connected with the superconducting cavity and is configured to provide a cavity vacuum environment and an interlayer vacuum environment required by operation for the superconducting cavity; and the coupler is connected with the coupling port of the superconducting cavity and is configured to feed radio frequency power into the superconducting cavity. The invention gets rid of the working mode that the traditional superconducting cavity is cooled by soaking in liquid helium, on one hand, the layout is compact, the arrangement is simple, the maintenance is convenient, the maintenance period is long, the application is simple, and the difficulty and the cost of the radio frequency superconducting technology in small-scale application can be obviously reduced; on the other hand, the manufacturing cost is far lower than that of the current liquid helium soaking type radio frequency superconducting accelerating unit, and the liquid helium soaking type radio frequency superconducting accelerating unit is very suitable for miniaturization and industrial application of a radio frequency superconducting technology.

The following describes the solid conduction cooling-based liquid-helium-free radio frequency superconducting acceleration module in detail with reference to the accompanying drawings.

As shown in fig. 1 and fig. 2, the liquid helium-free rf superconducting acceleration module provided in this embodiment includes: a superconducting cavity 1 configured to provide energy to a charged particle beam; a low temperature unit 2 configured to provide a required low temperature environment to the superconducting cavity 1; a vacuum unit 3 connected to the superconducting cavity 1, the vacuum unit 3 being configured to provide a cavity vacuum environment and an interlayer vacuum environment required for operation to the superconducting cavity 1; and a coupler 4 connected to the coupling port of the superconducting cavity 1, wherein the coupler 4 is configured to feed radio frequency power into the superconducting cavity 1.

In the above embodiment, preferably, the low temperature unit 2 includes: the cold screen 2-1 is covered outside the superconducting cavity 1, and the cold screen 2-1 is prepared to reduce the static heat loss of the superconducting cavity 1; a magnetic shield layer (not shown in the figure) arranged in the space between the cold shield 2-1 and the superconducting cavity 1, the magnetic shield layer being configured to shield the earth's ambient magnetic field, reducing the magnetic flux capture of the superconducting cavity 1; the three groups of cold-conducting copper blocks 2-2 are respectively arranged in the equator region of the superconducting cavity 1 and the beam pipeline regions at two sides along the circumferential direction, and the inner surface of the cold-conducting copper block 2-2 is attached to the equator region of the superconducting cavity 1 and the outer surface of the beam pipeline regions; the secondary cold plate 2-3 is arranged above the cold conducting copper blocks 2-2, and one side of the secondary cold plate 2-3 is respectively connected with the three groups of cold conducting copper blocks 2-2 through flexible cold chains 2-4; and at least one refrigerating machine 2-5 is arranged above the secondary cold plate 2-3, and a secondary cold head 2-6 of the refrigerating machine 2-5 is connected with the other side of the secondary cold plate 2-3 through a flexible cold chain 2-4. Therefore, the heat generated by the inner wall of the superconducting cavity 1 is transferred to the secondary cold plate 2-3 through the flexible cold chain 2-4 through the cold conducting copper block 2-2, and is transferred to the secondary cold head 2-6 of the refrigerator 2-5 through the flexible cold chain 2-4, so that the superconducting cavity 1 is maintained in a low-temperature superconducting working state. It should be noted that three groups of cold conducting copper blocks 2-2 are respectively arranged in the equator region of the superconducting cavity 1 and the beam pipeline regions on the two sides along the circumferential direction, only for the case that the superconducting cavity 1 is a single ellipsoidal cavity (i.e. an acceleration unit), but if the superconducting cavity 1 includes a plurality of acceleration units, the number of the cold conducting copper blocks 2-2 required is determined according to the application requirements; and, if the shape of the superconducting cavity 1 is not an ellipsoidal cavity, it is necessary to dispose the cold conducting copper block 2-2 in the heat generating region of the superconducting cavity 1.

In the above embodiment, preferably, the cold conducting copper block 2-2 is in a half-and-half hoop form, and the half-and-half hoops of the cold conducting copper block 2-2 are fastened and connected through screws and nuts; meanwhile, indium sheets (not shown in the figure) are uniformly arranged on the contact interface of the cold conducting copper block 2-2 and the superconducting cavity body 1 and the connection part of the half hoop and the half hoop for enhancing heat conduction; in addition, in order to reduce the residual magnetism of the space where the superconducting cavity 1 is located and effectively fasten, the used screw is a 316L stainless steel screw, the used nut is a silicon bronze nut, and the used gasket is a stainless steel elastic cushion; further, the fastening torque of the screw and the nut is 115N.m, and the thermal resistance of the fastening connection part is ensured to be lower than 1 x 10^-4Km²/W。

In the above embodiment, preferably, temperature sensors (not shown in the figure) are disposed at the outer surface of the equatorial region of the superconducting cavity 1, at the positions of the three sets of cold conducting copper blocks 2-2, the secondary cold plates 2-3, the secondary cold heads 2-6, and the like, for monitoring the temperature change of the superconducting cavity 1; meanwhile, a high-precision heater (not shown in the figure) is arranged on the secondary cold head 2-6 and is used for being matched with a temperature controller and a temperature sensor, so that the conditions that the cooling rate is stable between 30K and 15K and is continuously adjustable between 1min/K and 5min/K are realized, and the temperature gradient of the superconducting cavity 1 in the axial direction is ensured to be less than or equal to 0.025K/cm.

In the above embodiment, it is preferable that fluxgate probes (not shown in the figure) are arranged on the outer surface of the equator region of the superconducting cavity 1 and the outer surfaces of the beam pipe regions on both sides, and the fluxgate probes are required to be capable of accurately measuring the magnetic field strength of less than or equal to 10mGs for residual magnetism measurement and monitoring.

In the above embodiment, preferably, the vacuum unit 3 includes: the vacuum cover 3-1 is covered outside the cold screen 2-1, and the vacuum cover 3-1 is configured to form an interlayer vacuum environment for reducing static heat loss between the vacuum cover 3-1 and the superconducting cavity 1; one end of each of the two groups of vacuum pipelines 3-2 is respectively connected with two flow pipelines of the superconducting cavity 1 through a vacuum angle valve 3-3, and the other end of each of the two groups of vacuum pipelines 3-2 penetrates out of the vacuum cover 3-1 and then is connected with a vacuum pump set (not shown in the figure) so as to form a cavity vacuum environment for accelerating charged particles in a superconducting cavity-pipeline system consisting of the superconducting cavity 1 and the vacuum pipelines 3-2.

In the above embodiment, preferably, the leak rate of the chamber in the vacuum environment is not more than 5e-10mbarL/S at normal temperature, and the vacuum degree of the chamber in the vacuum environment is not more than 5e-5Pa at normal temperature; the vacuum degree of the interlayer vacuum environment is required to be less than or equal to 5e-8mbarL/S at normal temperature, and the vacuum degree of the interlayer vacuum environment is required to be less than or equal to 5e-3Pa at normal temperature.

In the above embodiment, preferably, the vacuum cover 3-1 is made of stainless steel, and the inner and outer surfaces are polished to reduce gas adsorption; the top of the vacuum cover 3-1 is provided with a butt joint port of a refrigerator 2-5, the side is provided with a butt joint port of a vacuum pipeline 3-2, and the bottom is provided with a butt joint port of a coupler 4; a temperature sensor wall penetrating piece 3-4 is reserved on the vacuum cover 3-1 and is used for butt joint of a data line of the temperature sensor; a magnetic probe sensor wall penetrating piece 3-5 is reserved on the vacuum cover 3-1 and is used for butt joint of data lines of the fluxgate probe; the vacuum cover 3-1 is reserved with a backfill port for high-purity nitrogen inflation vacuum recovery and pipeline cleaning, and the cleanliness of the device is guaranteed.

In the above embodiment, preferably, since the cavity wall loss of the superconducting cavity 1 is extremely small, the bandwidth is extremely narrow, and cavity vibration may cause frequency detuning of the superconducting cavity, so as to avoid that vibration of the refrigerator 2-5 is transmitted to the superconducting cavity 1 to affect stable operation thereof, the liquid-helium-free radio frequency superconducting acceleration module further comprises a damper 5 arranged at the top of the vacuum enclosure 3-1, and the refrigerator 2-5 is arranged on the damper 5, so that the vibration amplitude of the secondary cold head 2-6 of the refrigerator 2-5 butted with the superconducting cavity 1 is greatly reduced; meanwhile, the flexible cold chain 2-4 between the secondary cold head 2-6 of the refrigerator 2-5 and the superconducting cavity 1 can effectively prevent the vibration of the refrigerator 2-5 from being transmitted to the superconducting cavity 1.

In the above embodiment, preferably, the superconducting cavity 1 is supported in the vacuum enclosure 3-1 by the supporting structure 6 made of a non-magnetic material, and the fine tuning rod is arranged on the supporting structure 6, so that the position of the superconducting cavity can be fine tuned with high precision, and the requirement for collimation of the superconducting cavity 1 of the accelerator can be met.

In the above embodiment, it is preferable that the inner surface of the superconducting cavity 1 is formed with a thin film of a high-temperature superconducting material, i.e., a material having a superconducting transition temperature higher than 15K at zero magnetic field and a superheated magnetic field higher than 150mT at 4K, such as Nb₃Sn、MgB₂NbN, iron-based superconducting materials, and the like.

It should be understood by those skilled in the art that the drawings and the implementation of the present invention are only for convenience of describing the technical solution of the present invention, and the schematic illustration and description are given by taking as an example the liquid helium-free rf superconducting acceleration module with a superconducting cavity of one shape and the method for using the same, and do not indicate or imply that the superconducting cavity and the solid conductive cooling structure design in question must have specific shape, size and material limitations, and therefore the scope of protection of the present invention should not be limited thereby. All applications that use a refrigerator-driven cooling method based on solid conduction to accelerate charged particles are within the scope of the present invention.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.