A linear accelerator vacuum system and method of use thereof

Abstract

The application relates to the technical field of linear accelerators, in particular to a linear accelerator vacuum system and a using method thereof; a first high-vacuum ion pump is arranged at the joint of an electron gun and an accelerating tube of the system, a five-way pipe is connected to the lower end of the accelerating tube, the lower port of the five-way pipe is connected to a scanning box through a vacuum plug valve, the other three ports of the five-way pipe are respectively connected to two second high-vacuum ion pumps and a first vacuum angle valve; two third high-vacuum ion pumps are arranged on the scanning box, the gas inlet ends of the third high-vacuum ion pumps are communicated with the scanning box, and a second vacuum angle valve is further connected to the scanning box; the application adopts a novel vacuum system constitution scheme, can more uniformly generate and maintain vacuum, and can detect the vacuum effect at multiple points. The vacuum plug valve can isolate the vacuum of two subsystems, and the two subsystems are convenient for being respectively detected and transported; meanwhile, the vacuum angle valves are installed at multiple points, an external high-efficiency vacuum system can be connected, and the vacuum extraction efficiency of the system is improved.

Description

Technical Field

[0001] This invention relates to the field of linear accelerator technology, specifically a linear accelerator vacuum system and its usage method. Background Technology

[0002] The vacuum system of a linear accelerator ensures that accelerated electrons are in a vacuum state during generation, acceleration, and extraction. Electrons are generated in the electron gun, accelerated in the accelerating tube, and finally guided through a scanning box before exiting the system. The entire system is approximately several meters long and typically consists of a low-vacuum pump to generate a low vacuum, followed by a high-vacuum pump to generate and maintain a high vacuum. Electrons striking any object during their motion will release gas, causing a decrease in vacuum. Even minor damage to the beam system can lead to a severe decrease in vacuum. A decrease in vacuum can cause electron gun oxidation and failure, reduced system performance, and even complete damage to related equipment.

[0003] Currently, most accelerators use a series of high and low vacuum pumps installed in the relatively simple scanning box to generate and maintain the vacuum system. Since the vacuum effect maintained by the pump gradually decreases with distance from the pump, this system uses high-power equipment to ensure better vacuum for the electron gun, which is far from the scanning box. Furthermore, while the series connection of the high and low vacuum pumps can directly generate and maintain a high vacuum, the low vacuum system cannot be shut down during the maintenance phase; otherwise, the vacuum effect will be compromised. This results in high energy consumption and low efficiency for the vacuum system.

[0004] Furthermore, due to the length of the entire beam system and the large number of related components, if a vacuum leak occurs in any part, the entire system needs to be inspected. Since even the smallest leak can cause system failure, troubleshooting is extremely difficult. Also due to its length, the entire beam system is difficult to transport and install.

[0005] In addition, in order to measure the vacuum level of the beam system, existing linear accelerators have holes drilled in the equipment to install vacuum gauges, which increases the risk of vacuum leakage in the system. Summary of the Invention

[0006] To address the above problems, this invention provides a linear accelerator vacuum system and its usage method.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by this invention is as follows:

[0008] A linear accelerator vacuum system includes an electron gun, an accelerator tube, and a scanning box. The electron gun is mounted on the upper end of the accelerator tube. A first high-vacuum ion pump is provided at the connection between the electron gun and the accelerator tube. The lower end of the accelerator tube is connected to a five-way pipe. The lower port of the five-way pipe is connected to the scanning box through a vacuum gate valve. The other three ports of the five-way pipe are respectively connected to two second high-vacuum ion pumps and a first vacuum angle valve.

[0009] The scanning box is equipped with two third high-vacuum ion pumps, the inlet of which is connected to the scanning box. A second vacuum angle valve is also connected to the scanning box.

[0010] Furthermore, the inlet end of the first high-vacuum ion pump is connected to the upper end of the acceleration tube via a pipe.

[0011] Preferably, the inlet of one of the third high-vacuum ion pumps is connected to the scanning box via a three-way pipe, and the other end of the three-way pipe is connected to the second vacuum angle valve.

[0012] Furthermore, the upper end of the five-way pipe is connected to the acceleration tube via a flange, the lower end of the five-way pipe is connected to the vacuum slide valve, the lower end of the vacuum slide valve is connected to the scanning box via a flange, two second high-vacuum ion pumps are respectively connected to the front and rear ports of the five-way pipe, and the remaining port of the five-way pipe is connected to the first vacuum angle valve.

[0013] Furthermore, the third high-vacuum ion pump is installed on both sides of the scanning box.

[0014] Furthermore, an ammeter is installed in the power supply circuit of each high-vacuum ion pump.

[0015] This invention employs a novel vacuum system configuration, installing vacuum pumps at multiple points to generate and maintain a more uniform vacuum, and enabling multi-point monitoring of the vacuum effect. A vacuum gate valve is installed at the connection between the accelerating tube and the scanning box to isolate the vacuum of the two subsystems, facilitating separate testing and transportation. Simultaneously, the installation of vacuum angle valves at multiple points allows for connection to an external high-efficiency vacuum system to generate a vacuum, improving the system's evacuation efficiency.

[0016] The present invention also provides a method of using the above-mentioned linear accelerator vacuum system, comprising:

[0017] 1) Close the vacuum gate valve, assemble the electron gun and acceleration tube to form a vacuum chamber, connect the high and low vacuum units in series to the first vacuum angle valve and open the first vacuum angle valve, start the high and low vacuum units in series to pump to the required vacuum level, and then start the second high vacuum ion pump and the first high vacuum ion pump to maintain the vacuum.

[0018] Connect the high and low vacuum units in series to the second vacuum angle valve and open the second vacuum angle valve. Start the high and low vacuum units in series to pump to the required vacuum level. Then start the third high vacuum ion pump to maintain the vacuum.

[0019] 2) Close the first vacuum angle valve and the second vacuum angle valve and disconnect the external series high and low vacuum pump group. Then open the vacuum gate valve to connect the electron gun, acceleration tube and scanning box.

[0020] 3) The vacuum status at this location is determined by monitoring the current changes of the ammeters connected to each high-vacuum ion pump.

[0021] Furthermore, in step 3), the vacuum state is determined by monitoring the current changes of the ammeters connected to each high-vacuum ion pump; specifically:

[0022] When the current displayed on the ammeter connected to a high-vacuum ion pump increases at a certain location, it indicates the presence of gas at that location, causing a decrease in vacuum.

[0023] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0024] 1) This invention uses a multi-point installed high vacuum ion pump, which provides a uniform vacuum effect and eliminates the need for a series vacuum pump to maintain the vacuum. The mechanical structure is simple and energy-saving.

[0025] 2) The vacuum slide valve in this invention can separate the vacuum space, reducing the difficulty of maintenance and transportation.

[0026] 3) In this invention, the ammeter connected in series with the high vacuum ion pump installed at multiple points can replace the leak detection effect of the vacuum gauge, avoiding the risk of system vacuum leakage caused by the installation of the vacuum gauge through an opening.

[0027] 4) In this invention, multiple vacuum angle valves are installed, which can be connected to high and low vacuum pump groups in series to establish vacuum in stages. After the vacuum is established, the series vacuum pumps can be removed, which improves the efficiency of the system's vacuuming. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is an axonometric view of the present invention;

[0030] Figure 2 This is an enlarged view of the five-way pipe section in this invention.

[0031] The labels in the diagram are as follows:

[0032] Electron gun-1; Accelerator tube-2; Scanner box-3; First high vacuum ion pump-4; Second high vacuum ion pump-5; First vacuum angle valve-6; Vacuum gate valve-7; Third high vacuum ion pump-8; Second vacuum angle valve-9; Five-way pipe-10. Detailed Implementation

[0033] To make the objectives, 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 accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] See attached document Figure 1-2 As shown, this embodiment provides a linear accelerator vacuum system, including an electron gun 1, an accelerator tube 2, and a scanning box 3. The electron gun 1 is installed at the upper end of the accelerator tube 2. A first high-vacuum ion pump 4 is provided at the connection between the electron gun 1 and the accelerator tube 2. In this embodiment, the first high-vacuum ion pump 4 is a 25L high-vacuum ion pump. The inlet end of the first high-vacuum ion pump 4 is connected to the upper end of the accelerator tube 2 through a pipe. The lower end of the accelerator tube 2 is connected to a five-way pipe 10. The lower port of the five-way pipe 10 is connected to the scanning box 3 through a vacuum gate valve 7. The other three ports of the five-way pipe 10 are respectively connected to two second high-vacuum ion pumps 5 and a first vacuum angle valve 6. The first vacuum angle valve 6 is connected at one end to the five-way pipe 10, and the other end can be connected to a series of high and low vacuum pump groups to improve the vacuuming efficiency of the system.

[0035] In this embodiment, the upper end of the five-way pipe 10 is connected to the accelerating tube 2 via a flange, and the lower end of the five-way pipe 10 is connected to the vacuum gate valve 7. The lower end of the vacuum gate valve 7 is connected to the scanning box 3 via a flange. Two second high-vacuum ion pumps 5 are respectively connected to the front and rear ports of the five-way pipe 10, and the remaining port of the five-way pipe 10 is connected to the first vacuum angle valve 6. The aforementioned second high-vacuum ion pumps are 25L high-vacuum ion pumps. The vacuum gate valve 7 is located between the accelerating tube 2 and the scanning box 3. After the vacuum gate valve is closed, the vacuum systems of the upper and lower sections are independent, allowing for separate vacuum leak detection. After the vacuum gate valve is closed, the scanning box can be removed while maintaining the vacuum in the accelerating tube.

[0036] The scanning box 3 is equipped with two third high vacuum ion pumps 8, which are installed on both sides of the scanning box 3. The inlet end of the third high vacuum ion pump 8 is connected to the scanning box 3. The scanning box 3 is also connected with a second vacuum angle valve 9. The other end of the second vacuum angle valve 9 on the scanning box 3 can be connected to a series of high and low vacuum pump groups to improve the vacuuming efficiency of the system.

[0037] In this embodiment, the inlet end of the third high vacuum ion pump 8 is connected to the scanning box 3 through a three-way pipe, and the other end of the three-way pipe is connected to the end of the second vacuum angle valve 9. The third high vacuum ion pump 8 is a 50L high vacuum ion pump.

[0038] Install an ammeter in the power supply circuit of all the high-vacuum ion pumps mentioned above. The working principle of a high-vacuum ion pump is: it uses high-voltage electrodes to adsorb gas particles in the space, and the adsorbed particles will discharge on the electrodes. Installing an ammeter in the circuit of all high-vacuum ion pumps can detect the current change caused by the weak discharge and determine the vacuum state at that point.

[0039] The first, second, and third high-vacuum ion pumps mentioned above are only used to maintain a high vacuum state. When the system needs to generate a high vacuum, the first and second vacuum angle valves can be used to connect to the series high and low vacuum pump groups. The vacuum pump groups will provide greater efficiency to generate a vacuum. When the vacuum reaches the required level, the angle valves can be closed and the vacuum pump groups can be removed.

[0040] During accelerator operation, five high-vacuum ion pumps are distributed at different locations, each maintaining an optimal vacuum level within its respective range without causing significant regional vacuum decline. Simultaneously, ammeters installed in the high-vacuum ion pump circuits detect current changes caused by weak discharges, determining the vacuum state at that location. When the current displayed on the ammeter connected to a high-vacuum ion pump increases at a certain point, it can be assumed that gas has entered that area, causing a decrease in vacuum. This design eliminates the need for additional openings and vacuum gauges.

[0041] This embodiment also provides a method for using the above-mentioned linear accelerator vacuum system, including:

[0042] 1) Leak detection test:

[0043] Close the vacuum gate valve 7, assemble the electron gun 1 and the accelerating tube 2 to form a vacuum chamber, connect the high and low vacuum units in series to the first vacuum angle valve 6 and open the first vacuum angle valve 6, start the high and low vacuum units in series to pump to the required vacuum level, then start the second high vacuum ion pump 5 and the first high vacuum ion pump 4 to maintain the vacuum; then use professional vacuum degree detection equipment to perform vacuum leak detection tests on the accelerating tube and electron gun.

[0044] Connect the high and low vacuum units in series to the second vacuum angle valve 9 and open the second vacuum angle valve 9. Start the high and low vacuum units in series to pump to the required vacuum level. Then start the third high vacuum ion pump 8 to maintain the vacuum. Subsequently, use professional vacuum level detection equipment to perform a vacuum leak test on the scanning box.

[0045] 2) Establish a vacuum:

[0046] After completing the leak test, close the first vacuum angle valve 6 and the second vacuum angle valve 9 and disconnect the external series high and low vacuum pump groups. Then open the vacuum gate valve 7 to connect the electron gun 1, the acceleration tube 2, and the scanning box 3.

[0047] 3) Monitor vacuum status:

[0048] The vacuum state at this location is determined by monitoring the current changes of the ammeters connected to each high-vacuum ion pump; specifically:

[0049] When the ammeter connected to a high-vacuum ion pump shows an increased current, it indicates the presence of gas at that location, causing a decrease in vacuum. No additional drilling or vacuum gauge is required.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A linear accelerator vacuum system, comprising an electron gun (1), an accelerator tube (2), and a scanning box (3), wherein the electron gun (1) is mounted on the upper end of the accelerator tube (2), characterized in that, A first high-vacuum ion pump (4) is provided at the junction of the electron gun (1) and the accelerating tube (2). The lower end of the accelerating tube (2) is connected to a five-way pipe (10). The lower port of the five-way pipe (10) is connected to the scanning box (3) through a vacuum insert valve (7). The other three ports of the five-way pipe (10) are respectively connected to two second high-vacuum ion pumps (5) and a first vacuum angle valve (6). The scanning box (3) is equipped with two third high vacuum ion pumps (8), the inlet of the third high vacuum ion pumps (8) is connected to the scanning box (3), and a second vacuum angle valve (9) is also connected to the scanning box (3).

2. The linear accelerator vacuum system according to claim 1, characterized in that, The inlet of the first high vacuum ion pump (4) is connected to the upper end of the acceleration tube (2) through a pipe.

3. A linear accelerator vacuum system according to claim 1, characterized in that, The inlet of one of the third high vacuum ion pumps (8) is connected to the scanning box (3) via a three-way pipe, and the other end of the three-way pipe is connected to the second vacuum angle valve (9).

4. A linear accelerator vacuum system according to claim 1, characterized in that, The upper end of the five-way pipe (10) is connected to the acceleration tube (2) via a flange, the lower end of the five-way pipe (10) is connected to the vacuum slide valve (7), the lower end of the vacuum slide valve (7) is connected to the scanning box (3) via a flange, two second high vacuum ion pumps (5) are respectively connected to the front and rear ports of the five-way pipe (10), and the remaining port of the five-way pipe (10) is connected to the first vacuum angle valve (6).

5. A linear accelerator vacuum system according to claim 1, characterized in that, The third high-vacuum ion pump (8) is installed on both sides of the scanning box (3).

6. A linear accelerator vacuum system according to claim 1, characterized in that, An ammeter is installed in the power supply circuit of each high vacuum ion pump.

7. A method of using the linear accelerator vacuum system as described in claim 6, characterized in that, include: 1) Close the vacuum gate valve (7), assemble the electron gun (1) and the acceleration tube (2) to form a vacuum chamber, connect the high and low vacuum units in series on the first vacuum angle valve (6) and open the first vacuum angle valve (6), start the high and low vacuum units in series to pump to the required vacuum level, and then start the second high vacuum ion pump (5) and the first high vacuum ion pump (4) to maintain the vacuum. Connect the high and low vacuum units in series to the second vacuum angle valve (9) and open the second vacuum angle valve (9). Start the high and low vacuum units in series to pump to the required vacuum level. Then start the third high vacuum ion pump (8) to maintain the vacuum. 2) Close the first vacuum angle valve (6) and the second vacuum angle valve (9) and disconnect the external series high and low vacuum pump group. Then open the vacuum plug valve (7) to connect the electron gun (1), the acceleration tube (2) and the scanning box (3). 3) The vacuum status at this location is determined by monitoring the current changes of the ammeters connected to each high-vacuum ion pump.

8. The method of using the linear accelerator vacuum system according to claim 7, characterized in that, In step 3), the vacuum state is determined by monitoring the current changes of the ammeters connected to each high-vacuum ion pump; specifically: When the current displayed on the ammeter connected to a high-vacuum ion pump increases at a certain location, it indicates the presence of gas at that location, causing a decrease in vacuum.

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