Built-in vacuum exhaust pump for compact intense-current cyclotron

Abstract

The application discloses a built-in vacuum exhaust pump of a compact strong current cyclotron, and has the characteristics that the built-in vacuum exhaust pump utilizes the spatial position of a valley area of the cyclotron, penetrates into the valley area from a lower cover plate of the cyclotron, is inserted upwards in the valley area to the vicinity of a central plane of the cyclotron, and directly exhausts vacuum to the central plane of the cyclotron. The built-in low-temperature pump structure design is adopted, 1) the space of the valley area of the cyclotron is reasonably utilized, the condensation and adsorption area of a cold umbrella is doubled, the gas adsorption saturation capacity of the cyclotron is also doubled, the continuous working time of the low-temperature pump is prolonged, and the regeneration frequency is reduced; 2) compared with an external low-temperature pump, the effective exhaust speed of the low-temperature pump is improved because of no limitation of a through guide; and 3) the overall size of the cyclotron can be greatly reduced, and the protection cost of the cyclotron is reduced.

Description

Technical Field

[0001] This invention relates to the field of accelerator vacuum, and more specifically to a built-in vacuum exhaust pump for a compact high-current cyclotron accelerator. Background Technology

[0002] A cyclotron is a particle accelerator whose core structure consists of a magnetic field system and a radio frequency (RF) system. Under the combined influence of the magnetic and electric fields, charged particles undergo cyclotronic motion, and are repeatedly accelerated by a high-frequency electric field. To prevent energy loss from collisions with other atoms during their motion, high-vacuum operating conditions are required. For compact cyclotrons, given their compact structure, diverse equipment, high vacuum requirements, limited conductivity, and increasing miniaturization demands, the rational utilization of every spatial component of the accelerator is imperative.

[0003] Existing technologies all employ external vacuum generation equipment, which not only occupies a large space but also cannot achieve sufficiently high pumping speeds, becoming a major constraint on further improving the vacuum level of accelerators. Therefore, there is an urgent need to design a vacuum exhaust device specifically for compact cyclotron accelerators. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a built-in vacuum exhaust pump for a compact high-current cyclotron accelerator. The purpose is to solve the high vacuum and miniaturization requirements of the accelerator, effectively reducing vacuum stripping losses of particles during the acceleration process, which is of great significance for the further engineering application of accelerators.

[0005] To solve its technical problems, the present invention proposes the following technical solutions:

[0006] A built-in vacuum exhaust pump for a compact high-current cyclotron accelerator is disclosed. This built-in vacuum exhaust pump utilizes the spatial location of the accelerator's valley region, inserting upwards from the lower cover plate to near the accelerator's central plane corresponding to the valley region, to directly evacuate the accelerator's central plane. The built-in vacuum exhaust pump includes a cryogenic cold head and a built-in cryogenic condensation and adsorption device. The cryogenic cold head provides primary and secondary cooling to the cold screen and cold umbrella of the built-in cryogenic condensation and adsorption device. The built-in cryogenic condensation and adsorption device utilizes the cryogenic surface of the cold umbrella to condense, adsorb, and capture condensable gases in the accelerator's vacuum chamber, thereby achieving the effect of evacuating the accelerator's vacuum chamber.

[0007] Its features are: the built-in low-temperature condensation adsorption device is equipped with a baffle to prevent high-energy particles from entering the cold screen from the central plane of the accelerator; the number of cold umbrellas of the built-in low-temperature condensation adsorption device can be increased or decreased according to the size of the valley space of the accelerator.

[0008] Furthermore, the housing of the built-in low-temperature condensation adsorption device is a cylindrical cold screen, which contains the primary and secondary cold heads of the low-temperature cold head, and is equipped with a baffle and a cold umbrella. The cold screen is connected to the primary cold head through a cold screen bracket. The baffle is arranged at one end of the cold screen near the center plane of the accelerator to prevent high-energy particles and dust from entering the cold screen. The cold umbrella is arranged on a cold umbrella bracket and is connected to the secondary cold head through the cold umbrella bracket.

[0009] Furthermore, the built-in vacuum exhaust pump is inserted near the accelerator center plane corresponding to the valley region, that is: the side of the cold screen near the accelerator center plane is 30-50mm lower than the upper surface of the magnetic pole, in order to reduce the loss of high-energy particles on the cold screen, cold umbrella, and baffle.

[0010] Furthermore, the number of cooling umbrellas can be increased or decreased according to the size of the accelerator valley space. Specifically, the number of cooling umbrellas is calculated based on the diameter of the cooling screen: the diameter of the cooling screen is smaller than the diameter of the accelerator valley aperture, which is 10mm. <DC-DP<20mm。

[0011] Furthermore, the number of cooling umbrellas can be increased or decreased according to the size of the accelerator valley space. Specifically, the number of cooling umbrellas includes 6; when the number of cooling umbrellas is greater than 3, the diameter of the cooling umbrellas increases sequentially from top to bottom, increasing the probability of gas passage, i.e., conduction, and improving the utilization rate of the cooling umbrellas; the distance between the cooling umbrellas is L = 35~45mm.

[0012] Furthermore, the baffle is composed of multiple circular rings arranged on the same horizontal plane with a certain distance between them, each with a smaller upper opening and a larger lower opening, and the overlap between the upper opening of one ring and the lower opening of the next ring does not exceed 10%.

[0013] Furthermore, the "smaller upper opening and larger lower opening" means that the side of the ring closer to the center plane of the accelerator is the upper opening, and the side of the ring farther from the center plane of the accelerator is the lower opening, with an inclination angle of 45 degrees between the upper and lower openings.

[0014] Furthermore, activated carbon is adhered to the inner surface of the cooling umbrella to enhance its adsorption capacity for gases such as H2 and He.

[0015] Furthermore, heaters are installed on the cold screen and cold umbrella respectively, and the power of each heater is independently controlled to achieve rapid rewarming of the cold screen and cold umbrella and reduce the regeneration time of the cryogenic pump.

[0016] Furthermore, temperature sensors are installed on the cold screen and the cold umbrella respectively to monitor the heat power load of the primary and secondary cold heads of the refrigeration unit. When the temperature exceeds a certain set value (e.g., 60K for the cold screen and 12K for the secondary cold umbrella), an alarm is triggered to prepare for the rewarming and regeneration of the cryogenic pump.

[0017] Advantages and effects of the present invention

[0018] By adopting a built-in cryogenic pump structure design, 1) the space in the accelerator valley area is rationally utilized, doubling the condensation and adsorption area of ​​the cold umbrella, and correspondingly doubling the gas adsorption saturation capacity of the accelerator, thereby increasing the continuous working time of the cryogenic pump and reducing the number of regeneration cycles; 2) compared to an external cryogenic pump, since there is no limitation on conduction, the actual pumping speed is theoretically equal to the pumping speed of the cryogenic pump, thus improving the effective pumping speed of the cryogenic pump; 3) the overall size of the accelerator can be greatly reduced, lowering the protection cost of the accelerator. Attached Figure Description

[0019] Figure 1 This is a top view showing the application effect of the built-in low-temperature condensation adsorption device of the cyclotron accelerator of the present invention;

[0020] Figure 2 This is a cross-sectional view showing the application effect of the built-in low-temperature condensation adsorption device of the cyclotron accelerator of the present invention.

[0021] Figure 3 This is a structural diagram of the built-in low-temperature condensation adsorption device of the cyclotron accelerator of the present invention;

[0022] Figure 4 This is a schematic diagram of the built-in low-temperature condensation adsorption device - cold umbrella of the cyclotron accelerator of the present invention;

[0023] Figure 5 This is a schematic diagram of the built-in low-temperature condensation adsorption device of the present invention—the cooling umbrella support.

[0024] Figure 6 This is a structural diagram of a low-temperature cold head;

[0025] Figure 7 This is an enlarged view of the built-in low-temperature condensation adsorption device of the present invention - the cooling umbrella;

[0026] Figure 8 This is an enlarged view of the baffle plate of the built-in low-temperature condensation adsorption device of the present invention;

[0027] Figure 9 This is a comparison diagram of the built-in vacuum exhaust pump of this invention and the external vacuum exhaust pump of the prior art;

[0028] In the diagram: 1: Low-temperature cold head; 1-1: Primary cooling capacity; 1-2: Secondary cooling capacity; 2: Built-in low-temperature condensation adsorption device; 2-1: Cold shield; 2-1-1: Cold shield temperature sensor; 2-1-2: Cold shield heater; 2-2: Baffle; 2-3: Cold umbrella; 2-3-1: Cold umbrella temperature sensor; 2-3-2: Cold umbrella heater; 2-3-3: Cold umbrella support; Detailed Implementation

[0029] Design principle of this invention:

[0030] 1. Design Challenges of this Invention: One challenge lies in installing the vacuum exhaust pump near the accelerator's central plane inside the accelerator. While this effectively solves the conduction loss problem, it introduces new issues: scattered particles, which act as a thermal load, will scatter near the accelerator's central plane. If not handled properly, these thermal loads will hit the cooling umbrella, rendering the vacuum exhaust pump ineffective. Existing technology installs the vacuum exhaust pump outside the accelerator's top cover, avoiding this problem because the scattered particles from the accelerator's central plane are far from and shielded by the cover. In this embodiment, to shorten the evacuation path and address the conduction loss caused by the long path, the vacuum exhaust pump's evacuation port is installed very close to the accelerator's central plane. This makes it easier for scattered particles to enter the vacuum exhaust pump. However, reducing the area of ​​the evacuation port to avoid particle scattering would also affect the evacuation process. Therefore, the design challenge lies in finding a balance between maintaining the unobstructed flow of the vacuum vent and preventing scattered particles from entering the vacuum exhaust pump. A second challenge is that existing vacuum exhaust pumps are general-purpose pumps, and their saturation capacity is far from meeting the vacuum requirements of the cyclotron, necessitating increased saturation capacity and a redesign. Increasing the saturation capacity involves increasing the number of cooling umbrellas; however, since the total cooling capacity of the refrigerator is fixed, increasing the number of cooling umbrellas will absorb additional cooling, thus increasing the total cooling capacity while increasing the saturation capacity. Therefore, the design challenge lies in balancing maximizing cooling capacity with maximizing saturation capacity.

[0031] 2. Solution of the present invention:

[0032] First, the design principle of the baffle: ① The function of the baffle is to reflect scattered particles from the central plane of the accelerator back. When the baffle ring is tilted at a smaller upper opening and a larger lower opening, scattered particles from all directions hitting the baffle will be reflected back by the reflective force. Conversely, if the baffle ring is tilted at a larger upper opening and a smaller lower opening, the reflective force will draw the scattered particles into the cold plate. When the scattered particles are drawn into the cold plate, the surface of the cold umbrella receives a heat load, and the temperature rises, preventing condensation and thus preventing the adsorption of condensable gases to achieve the vacuuming effect. ② The superposition of baffle rings: If there are gaps between the rings without superposition, scattered particles may hit the cold umbrella through the gaps. However, if the baffle rings are superimposed too much, it will affect the pumping of the cold umbrella. Since adding a baffle in front of the cold umbrella adds a layer of obstruction, this obstruction should be as small as possible while ensuring that the heat load does not hit the cold umbrella. Therefore, this invention designs the lower opening of the current baffle ring and the upper opening of the adjacent ring to have a radial superposition of no more than 10% of the ring radius.

[0033] Second, Design Principle of the Number of Cold Shields

[0034] 1) Determine the cooling capacity of the cryocooler according to the spatial size of the accelerator;

[0035] 2) Determine the size of the cold shield according to the size of the accelerator valley area, that is, the diameter of the cold shield is smaller than the diameter of the hole in the accelerator valley area, 10mm < DC - DP < 20mm; DC is the diameter of the hole in the accelerator valley area, and DP is the outer diameter of the cold shield;

[0036] 3) Determine the height of the cold shield: The height of the cold shield needs to be lower than the upper surface of the magnetic pole, H = 30 - 50mm;

[0037] 4) Initially determine the size and number of cold shields according to the size of the cold shield and the cooling capacity of the cryocooler to maximize the pumping capacity of the built-in cryopump and the saturation capacity of condensable gases. Specifically: When the number of cold shields is greater than 3, from top to bottom, the diameter of the cold shields increases in turn, increasing the gas passage probability, that is, the conductance, and improving the utilization rate of the cold shields; the distance between cold shields is L = 35 - 45mm.

[0038] 5) Determine the cooling capacity of the cold shield. After the basic dimensions are determined, calculate the total cooling capacity of the cold shield according to Formula (1) and Formula (2);

[0039] 6) Calculate its pumping speed according to the total cooling capacity of the cold shield and Formula (3), and optimize through repeated iterative calculations to finally determine the size and number of cold shields.

[0040] The above Formula (1), Formula (2), and Formula (3) are calculated as follows:

[0041]

[0042] In the above formula, Q1 is the radiant heat of the first-stage cold shield to the second-stage cold shield; TC is the temperature of the cryo-adsorption surface (K), TC = 10K; TB is the temperature of the gas baffle (K), TB = 77K; σ is the Stefan-Boltzmann constant, 5.7×10-12 W·cm-2·K-4; A is the area of the cryo-adsorption surface (cm2); ε C is the emissivity of the cryo-plate adsorption surface. After polishing the cryo-plate, its emissivity is generally 0.1. However, considering the influence of adsorbents, etc., the emissivity is taken as 0.4 according to experience; ε B is the emissivity of the gas baffle. By blackening the inner surface of the baffle, it can ensure that most of the transmitted heat load is absorbed by the baffle and very little is reflected onto the adsorption plate, thereby reducing its heat load. Its emissivity can be taken as 0.8. The heat Q2 transmitted through the gas baffle is:

[0043]

[0044] In the above formula, Q2 is the heat transmitted through light reflection via the gas baffle; tp is the transmittance coefficient of the herringbone baffle, which is taken as 0.022 when the baffle is blackened; TW is the temperature of the vacuum container wall (K), TW = 293K; and TC is the temperature of the secondary cooling array (K), TC = 10K. The heat transfer Q3 of the pumped gas includes the heat released by the pumped gas cooling down to the adsorption surface and the heat released by the adsorption of the pumped gas on the adsorption surface, as given by the formula:

[0045]

[0046] In the above formula, Q3 is the thermal conductivity of the pumped gas; M is the molar mass; R is the molar gas constant; p is the indoor pressure; ΔT is the temperature difference of the pumped gas; Δh is the heat of adsorption of the pumped gas, and the heat of adsorption of hydrogen on activated carbon is 7.83 kJ / mol; S is the theoretical pumping rate of the pumped gas.

[0047] The invention will now be further explained with reference to the accompanying drawings.

[0048] Based on the above-mentioned inventive principles, this invention designs a built-in vacuum exhaust pump for a compact high-current cyclotron accelerator, such as... Figure 1-9 As shown, the built-in vacuum exhaust pump utilizes the spatial position of the accelerator valley area, inserting upwards from the lower cover plate of the accelerator to the vicinity of the accelerator's central plane corresponding to the valley area, to directly evacuate the accelerator's central plane; the built-in vacuum exhaust pump includes a cryogenic cold head 1 and a built-in cryogenic condensation and adsorption device 2; the cryogenic cold head 1 is used to provide primary cooling capacity 1-1- and secondary cooling capacity 1-2 to the cold screen and cold umbrella of the built-in cryogenic condensation and adsorption device; the built-in cryogenic condensation and adsorption device 2 utilizes the cryogenic surface of the cold umbrella 2-3 to condense, adsorb, and capture condensable gases in the accelerator vacuum chamber, thereby achieving the effect of evacuating the accelerator vacuum chamber;

[0049] Its features are: the built-in low-temperature condensation adsorption device 2 is equipped with a baffle 2-2 to prevent high-energy particles from entering the cold screen from the central plane of the accelerator; the number of cold umbrellas 2-3 of the built-in low-temperature condensation adsorption device can be increased or decreased according to the size of the valley space of the accelerator.

[0050] Furthermore, the outer shell of the built-in low-temperature condensation adsorption device 2 is a cylindrical cold shield 2-1, which contains the primary cold head 1-1 and the secondary cold head 1-2 of the low-temperature cold head 1, and is equipped with a baffle 2-2 and a cold umbrella 2-3; as Figure 5 As shown, the cold screen is connected to the first-stage cold head 1-1 via the cold screen bracket 2-3-3; the baffle 2-2 is arranged at one end of the cold screen 2-1 near the center plane of the accelerator to prevent high-energy particles and dust from entering the cold screen 2-1; the cold umbrella 2-3 is arranged on the cold umbrella bracket 2-3-3 and is connected to the second-stage cold head 1-2 via the cold umbrella bracket 2-3-3.

[0051] Furthermore, the built-in vacuum exhaust pump is inserted near the accelerator center plane corresponding to the valley region, that is: the side of the cold screen 2-1 closest to the accelerator center plane is 30-50mm lower than the upper surface of the magnetic pole, in order to reduce the loss of high-energy particles on the cold screen, cold umbrella, and baffle.

[0052] Furthermore, the number of cooling umbrellas 2-3 can be increased or decreased according to the size of the accelerator valley space. Specifically, the number of cooling umbrellas 2-3 is calculated based on the diameter of the cooling screen 2-1: the diameter of the cooling screen 2-3 is smaller than the diameter of the accelerator valley hole, which is 10mm. <DC-DP<20mm。

[0053] Furthermore, the number of cooling umbrellas 2-3 can be increased or decreased according to the size of the accelerator valley space. Specifically, the number of cooling umbrellas 2-3 includes 6. When the number of cooling umbrellas 2-3 is greater than 3, the diameter of the cooling umbrellas increases sequentially from top to bottom, increasing the probability of gas passage and improving the utilization rate of the cooling umbrellas. The distance L between cooling umbrellas 2-3 is 35-45mm.

[0054] Furthermore, the baffle 2-2 is composed of multiple circular rings arranged on the same horizontal plane with a certain distance between them, each ring having a smaller upper opening and a larger lower opening, and the overlap between the upper opening of one ring and the lower opening of the next ring does not exceed 10%.

[0055] Supplementary Note 1:

[0056] The aforementioned "baffle is composed of multiple circular rings arranged on the same horizontal plane at a certain radial distance, with smaller openings at the top and larger openings at the bottom." These multiple circular rings are fixed to the cross on the baffle, and the cross is fixedly connected to the outer circle of the baffle.

[0057] Furthermore, the "smaller upper opening and larger lower opening" means that the side of the ring closer to the center plane of the accelerator is the upper opening, and the side of the ring farther from the center plane of the accelerator is the lower opening, with an inclination angle of 45 degrees between the upper and lower openings.

[0058] Furthermore, activated carbon is adhered to the inner surface of the cooling umbrella 2-3 to enhance its adsorption capacity for gases such as H2 and He.

[0059] Furthermore, heaters are installed on the cold screen 2-1 and the cold umbrella 2-3 respectively, and the power of each heater is independently controlled to achieve rapid rewarming of the cold screen and the cold umbrella, thereby reducing the regeneration time of the cryogenic pump.

[0060] Furthermore, temperature sensors are installed on the cold shield 2-1 and the cold umbrella 2-3 respectively to monitor the heat power load of the primary and secondary cold heads of the refrigeration unit. When the temperature exceeds a certain set value (e.g., 60K for the cold shield and 12K for the secondary cold umbrella), an alarm is triggered to prepare for the rewarming and regeneration of the cryogenic pump.

[0061] Supplementary Note 2:

[0062] ①For example Figure 3 As shown, firstly, the cooling umbrella heater 2-3-2 is installed on the second cooling head. When the machine needs to be stopped and the temperature is raised from 10K to 50K, the heating rate is fast because the heater 2-3-2 acts directly on the second cooling head. Secondly, the cooling umbrella temperature sensor 2-3-1 is installed on the first cooling umbrella blade with the highest temperature. Since the first cooling umbrella blade is closest to the center plane of the accelerator, that is, closest to the heat load, its temperature is the highest compared to other cooling umbrella blades.

[0063] ②For example Figure 3 As shown, the cold shield heater is 2-1-2, which is installed on the first-stage cold head. When it is necessary to stop the machine and raise the temperature from 50K to 300K room temperature, the heating speed is fast because the heater 2-1-2 acts directly on the first cold head. The cold shield temperature sensor is installed at the rear because the cold shield is connected to the baffle. Since there is a baffle at the front, the temperature sensor will be affected by the heat load splashed on the baffle. Therefore, the cold shield sensor is installed at the rear of the cold shield.

[0064] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A built-in vacuum exhaust pump for a compact high-current cyclotron accelerator, characterized in that: The built-in vacuum exhaust pump utilizes the spatial position of the accelerator valley area and is inserted upward from the lower cover plate of the accelerator to the vicinity of the accelerator center plane corresponding to the valley area, so as to directly evacuate the accelerator center plane. The built-in vacuum exhaust pump includes a low-temperature cold head (1) and a built-in low-temperature condensation and adsorption device (2); the low-temperature cold head is used to provide primary and secondary cooling capacity to the cold screen (2-1) and cold umbrella (2-3) of the built-in low-temperature condensation and adsorption device; the built-in low-temperature condensation and adsorption device (2) uses the low-temperature surface of the cold umbrella (2-3) to condense, adsorb, and capture condensable gases in the accelerator vacuum chamber, thereby achieving the effect of evacuating the accelerator vacuum chamber. The built-in low-temperature condensation adsorption device (2) is equipped with a baffle (2-2) to prevent high-energy particles from entering the cold screen from the central plane of the accelerator; the number of cold umbrellas (2-3) of the built-in low-temperature condensation adsorption device can be increased or decreased according to the size of the valley space of the accelerator.

2. The built-in vacuum exhaust pump for a compact high-current cyclotron accelerator according to claim 1, characterized in that: The built-in low-temperature condensation adsorption device (2) has a cylindrical cold screen (2-1) as its outer shell. The cylindrical cold screen (2-1) contains the first-stage cold head (1-1) and the second-stage cold head (1-2) of the low-temperature cold head, and is equipped with a baffle (2-2) and a cold umbrella (2-3). The cold screen (2-1) is connected to the first-stage cold head (1-1) through a cold screen bracket. The baffle (2-2) is arranged at one end of the cold screen (2-1) near the center plane of the accelerator to prevent high-energy particles and dust from entering the cold screen. The cold umbrella (2-3) is arranged on the cold umbrella bracket (2-3-3) and is connected to the second-stage cold head (1-2) through the cold umbrella bracket (2-3-3).

3. The built-in vacuum exhaust pump for a compact high-current cyclotron accelerator according to claim 2, characterized in that: The built-in vacuum exhaust pump is inserted near the center plane of the accelerator corresponding to the valley area. That is, the side of the cold screen (2-1) near the center plane of the accelerator is 30~50mm lower than the upper surface of the magnetic pole, in order to reduce the loss of high-energy particles on the cold screen (2-1), cold umbrella (2-3), and baffle (2-2).

4. The built-in vacuum exhaust pump for a compact high-current cyclotron accelerator according to claim 1, characterized in that: The number of cold umbrellas was calculated by examining the diameter of the cold screen: the diameter of the cold screen is smaller than the diameter of the accelerator valley aperture, by 10mm. <DC-DP<20mm。 5. The built-in vacuum exhaust pump for a compact high-current cyclotron accelerator according to claim 1, characterized in that: There are 6 cooling umbrellas. When the number of cooling umbrellas (2-3) is greater than 3, the diameter of the cooling umbrellas (2-3) increases from top to bottom, which increases the probability of gas passage, i.e., conduction, and improves the utilization rate of cooling umbrellas (2-3). The distance between cooling umbrellas (2-3) is L = 35~45mm.

6. The built-in vacuum exhaust pump for a compact high-current cyclotron accelerator according to claim 1, characterized in that: The baffle (2-2) is composed of multiple circular rings arranged on the same horizontal plane with a certain distance between them, each with a smaller upper opening and a larger lower opening, and the overlap between the upper opening of one ring and the lower opening of the next ring does not exceed 10%.

7. The built-in vacuum exhaust pump for a compact high-current cyclotron accelerator according to claim 6, characterized in that: The term "smaller upper opening and larger lower opening" means that the side of the ring closer to the center plane of the accelerator is the upper opening, and the side of the ring farther from the center plane of the accelerator is the lower opening, with an inclination angle of 45 degrees between the upper and lower openings.

8. The built-in vacuum exhaust pump for a compact high-current cyclotron accelerator according to claim 1, characterized in that: Activated carbon is adhered to the inner surface of the cooling umbrella (2-3).

9. The built-in vacuum exhaust pump for a compact high-current cyclotron accelerator according to claim 1, characterized in that: Heaters are installed on the cold screen (2-1) and cold umbrella (2-3) respectively, and the power of each heater is independently controlled to achieve rapid rewarming of the cold screen and cold umbrella and reduce the regeneration time of the cryogenic pump.

10. The built-in vacuum exhaust pump for a compact high-current cyclotron accelerator according to claim 1, characterized in that: Temperature sensors are installed on the cold shield (2-1) and cold umbrella (2-3) respectively to monitor the heat power load of the first-stage cold head (1-1) and the second-stage cold head (1-2) of the refrigeration unit. When the temperature is higher than a certain set value, an alarm is triggered to prepare for the rewarming and regeneration of the cryogenic pump. The certain set value includes 60K for the cold shield and 12K for the second-stage cold umbrella.

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