Coaxial direct-drive rotary radiation conversion target for high-energy X-rays

Abstract

The utility model discloses a coaxial direct-drive rotary radiation conversion target for high-energy X-rays, which comprises a tungsten target disc, a flange sleeve, a vacuum cavity shell, a motor mounting seat, a radiation-resistant motor, a magnetic fluid sealing shaft and a cooling assembly. The coaxial direct drive mode of the radiation-resistant motor and the tungsten target disc is adopted, and the coupling is further adopted for connection, so that vibration and noise caused by friction between two shafts during high-speed transmission are reduced, and the overall stability is improved; meanwhile, the radiation-resistant motor adopts the design of the hollow shaft, so that the requirement that the tungsten target disc needs to be provided with a cooling water path is met, the motor and a water cooler are arranged on the same side, and the space requirement of the whole conversion target is reduced.

Description

Technical Field

[0001] The utility model relates to the field of radiation devices, and more specifically, to a coaxial direct-drive rotating radiation conversion target for high-energy X-rays. Background Art

[0002] Most medical radiotherapy devices with ultra-high dose rates use MeV-level accelerators as X-ray sources, which have a high instantaneous dose rate and are particularly suitable for flash radiotherapy. During the generation of ultra-high dose rate X-rays, in order to ensure the safety of the radiation conversion target, a rotary liquid-cooled X-ray target has emerged. This target is driven by a motor and transmitted through a synchronous gear set to drive the radiation conversion target to rotate at a high speed, so that the electron beam bombarding the radiation conversion target is evenly smeared on the radiation conversion target, and the rotation speed of the target is set to an integer multiple of the non-electron beam pulse, avoiding the penetration of the target caused by multiple electron beams bombarding the same point. At the same time, a water-cooling method is used to cool the rotating target disk to ensure the heat resistance safety of the rotating target.

[0003] However, the previous method of motor drive + gear drive is prone to vibration of the target disk over time, ultimately resulting in poor symmetry of the X-ray dose in the radiation field, reduced stability, and even visible symmetry deterioration on the test film. Moreover, during high-speed rotation, the noise generated by gear drive makes the treatment experience of patients poor. At the same time, this side-drive method of "motor drive + gear drive" makes the treatment head of the radiotherapy device bulky and requires a higher radiotherapy space during the rotation of the treatment head. Summary of the Utility Model

[0004] The utility model overcomes the deficiencies of the prior art and provides a coaxial direct-drive rotating radiation conversion target for high-energy X-rays, in the hope of solving the problem of instability caused by gear drive in the prior art.

[0005] To solve the above technical problems, the utility model adopts the following technical solutions:

[0006] A coaxial direct-drive rotating radiation conversion target for high-energy X-rays includes a tungsten target disk, a flange sleeve, a vacuum chamber housing, a motor mounting seat, a radiation-resistant motor, a magnetic fluid sealing shaft, and a cooling assembly;

[0007] The tungsten target disk is installed inside the vacuum chamber housing, the motor mounting seat is installed outside the vacuum chamber housing, and the radiation-resistant motor is installed on the motor mounting seat;

[0008] The radiation-resistant motor adopts a structure with a hollow rotating shaft. One end of the magnetic fluid sealing shaft is fixedly connected to the tungsten target disk, and the other end passes through the rotating shaft of the radiation-resistant motor and is connected to the rotary joint in the cooling assembly;

[0009] The power output end of the shaft of the radiation-resistant motor matches the outer shape of the magnetohydrodynamic sealing shaft, and the two are flexibly connected; the cooling component circulates the cooling medium to cool the tungsten target disk, and the flange sleeve is installed on the magnetohydrodynamic sealing shaft and is hermetically connected to the vacuum chamber housing.

[0010] The radiation-resistant motor adopts a hollow shaft structure. The radiation-resistant motor directly drives the magnetohydrodynamic sealing shaft to prevent friction between the two shafts during gear transmission, resulting in vibration and noise during high-speed rotation.

[0011] A further technical solution is that the power output end of the shaft of the radiation-resistant motor matches the outer shape of the magnetohydrodynamic sealing shaft, and there is a flexible connection between the power output ends of the shafts of the radiation-resistant motor.

[0012] The purpose of the flexible connection is to achieve smooth transmission of rotation. The flexible connection can be a shock-absorbing ring, an elastic coupling, etc.

[0013] A further technical solution is that the shaft of the radiation-resistant motor is connected to the magnetohydrodynamic sealing shaft through a shock-absorbing ring, and the shock-absorbing ring is made of an elastic material.

[0014] The elastic shock-absorbing ring can further play a role in shock absorption.

[0015] A further technical solution is that the cooling component includes a rotary joint, a water inlet, a water outlet, and a water inlet pipe;

[0016] The rotary joint is installed at the tail of the magnetohydrodynamic sealing shaft and is connected to the magnetohydrodynamic sealing shaft;

[0017] The rotary joint is provided with a water inlet and a water outlet. One end of the water inlet pipe is communicated with the water inlet, and the other end passes through the magnetohydrodynamic sealing shaft and is communicated with the inlet of the cooling channel on the tungsten target disk. The outlet of the cooling channel on the tungsten target disk is communicated with the annular space gap between the water inlet pipe and the magnetohydrodynamic sealing shaft; the annular space gap between the water inlet pipe and the magnetohydrodynamic sealing shaft is communicated with the water outlet of the rotary joint;

[0018] The water inlet and the water outlet are the inlet end and the outlet end of the cooling medium. The water inlet of the tungsten target disk and the rotary joint can rotate relative to the water inlet pipe. Graphite rings are provided at both ends of the water inlet pipe.

[0019] The vacuum inner part of the magnetohydrodynamic sealing shaft is welded to the tungsten target disk, and the magnetohydrodynamic sealing shaft is a hollow shaft.

[0020] The tungsten target disk is circular, and the geometric center hole is the inlet of the cooling channel of the target disk. Cooling water is injected into the inlet of the cooling channel of the tungsten target disk through the water inlet pipe, circulates through the cooling channel in one of the spokes of the tungsten target disk to the cooling channel on the edge of the tungsten target disk, and finally returns to the outlet of the cooling channel of the tungsten target disk through the cooling channel in another spoke. The outlet of the cooling channel of the tungsten target disk is communicated with the annular space gap between the water inlet pipe and the magnetohydrodynamic sealing shaft, and then discharged from the water outlet of the rotary joint to achieve the purpose of cooling the tungsten target disk.

[0021] The cooling water path inside the magnetohydrodynamic sealing shaft is connected to the rotary joint, and the rotary joint has the function of preventing the water pipe from winding. The effect of the graphite ring is to prevent wear.

[0022] A further technical solution is that the coaxial direct-drive rotating radiation conversion target further includes a beam spot measurement target;

[0023] The beam spot measurement target includes a lifting mechanism and a YAG target. The YAG target is installed at the bottom of the lifting mechanism, and the beam spot measurement target is installed on the vacuum chamber housing.

[0024] According to actual needs, the YAG target is moved by the lifting mechanism. When it is necessary to measure the beam spot size, lower the YAG target so that the electron beam directly irradiates the center of the YAG target. When the electron beam bombards the YAG target to generate fluorescence, the spot is elliptical. Measuring the longitudinal length of the spot can obtain the size of the electron beam spot.

[0025] A further technical solution is that the installation direction of the YAG target forms a 45° angle with the incident direction of the electron beam.

[0026] A further technical solution is that the coaxial direct-drive rotating radiation conversion target further includes a bellows;

[0027] The bellows is installed on the vacuum chamber housing.

[0028] The bellows is an electron beam transmission pipeline. Its unique telescopic function can offset the installation error of the electron beam tube in the radial direction and at the same time play a role in damping the beam tube during the operation of the rotating target.

[0029] A further technical solution is that the coaxial direct-drive rotating radiation conversion target further includes an observation window;

[0030] The observation window is installed on the vacuum chamber housing, and the position of the observation window is aligned with the YAG target.

[0031] The observation window is used for beam spot measurement and provides a visual window.

[0032] A further technical solution is that the coaxial direct-drive rotating radiation conversion target further includes a magnetic rotary encoder;

[0033] The magnetic rotary encoder is installed on the radiation-resistant motor.

[0034] When the tungsten target disk rotates at a high speed, the high-energy electron beam bombards the tungsten target disk. It is necessary to stretch the time period when the electron beam bombards the same position on the tungsten target disk as much as possible, so that the heat deposited at the bombarded point on the tungsten target disk has enough conduction time and is fully carried away by the cooling medium to achieve the purpose of protecting the target disk. Therefore, the rotation speed of the tungsten target disk must be kept at a non-integer multiple of the electron beam pulse number. Thus, the monitoring and display of the target disk rotation speed are particularly important.

[0035] The magnetic rotary encoder has a certain radiation resistance. Even in an ultra-high radiation environment, it can maintain its characteristics such as high speed, high resolution, high precision, and strong anti-interference ability, and monitor the rotational motion and position change of the radiation-resistant motor.

[0036] A further technical solution is that the coaxial direct-drive rotating radiation conversion target further includes a magnetic Hall switch;

[0037] The magnetic Hall switch is installed on the cylindrical surface of the motor mounting seat.

[0038] In order to further detect whether the rotating target is operating at the set rotation speed, a magnetic Hall switch is installed on the cylindrical surface of the motor mounting seat to detect the rotation speed of the magnetic fluid sealing shaft.

[0039] The rotation speeds detected by the magnetic encoder and the magnetic Hall switch are compared with the actual rotation speed set for the motor in real time to determine whether the radiation rotating target is operating at the correct rotation speed and whether the running smoothness meets the set requirements, so as to ensure the normal operation of the radiation rotating target.

[0040] Compared with the prior art, the present utility model has at least the following beneficial effects: The present utility model adopts the coaxial direct-drive method of the radiation-resistant motor and the tungsten target disk, and further adopts a coupling connection, reducing the vibration and noise caused by the friction between the two shafts during high-speed transmission and improving the overall stability; at the same time, the radiation-resistant motor adopts a hollow shaft design to meet the requirement for arranging the cooling water path of the tungsten target disk; further, the present application also proposes a method of installing the YAG target at a 45° angle with the electron beam direction, making the electron beam measurement method more concise. Description of the Drawings

[0041] Figure 1 It is the overall structure diagram of the coaxial direct-drive rotating radiation conversion target for high-energy X-rays;

[0042] Figure 2 It is the axonometric view of the rotating radiation conversion target without the radiation-resistant motor;

[0043] Figure 3 It is the partial sectional view;

[0044] Figure 4 It is a sectional view taken along the A-A section;

[0045] In the figure, 1 - tungsten target disk, 2 - flange sleeve, 3 - vacuum chamber housing, 4 - motor mounting base, 5 - radiation-resistant motor, 50 - rotating shaft, 51 - shock-absorbing ring, 6 - magnetohydrodynamic sealing shaft, 7 - cooling assembly, 71 - rotary joint, 72 - water inlet, 73 - water outlet, 74 - water inlet pipe, 8 - beam spot measurement target, 9 - bellows, 10 - observation window. Specific implementation manner

[0046] In order to make the purpose, technical solutions and advantages of the present utility model clearer, the following further details the present utility model in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0047] A coaxial direct-drive rotary radiation conversion target for high-energy X-rays, see Figures 1 to 4 , including a tungsten target disk 1, a flange sleeve 2, a vacuum chamber housing 3, a motor mounting base 4, a radiation-resistant motor 5, a magnetohydrodynamic sealing shaft 6, a cooling assembly 7, a beam spot measurement target 8, a bellows 9, an observation window 10, a magnetic rotary encoder, and a magnetic Hall switch;

[0048] The tungsten target disk 1 is installed inside the vacuum chamber housing 3, the motor mounting base 4 is installed outside the vacuum chamber housing 3, and the radiation-resistant motor 5 is installed on the motor mounting base 4;

[0049] The rotating shaft 50 of the radiation-resistant motor 5 has a structure of a hollow rotating shaft. One end of the magnetohydrodynamic sealing shaft 6 is fixedly connected to the tungsten target disk 1, for example, connected together by welding. The other end of the magnetohydrodynamic sealing shaft 6 passes through the rotating shaft 50 of the radiation-resistant motor 5 and is connected to the rotary joint 71 in the cooling assembly 7. The power output end of the rotating shaft 50 of the radiation-resistant motor 5 matches the middle part of the magnetohydrodynamic sealing shaft 6 in shape and is flexibly connected between the two. Specifically, it is connected by a shock-absorbing ring 51 to achieve smooth transmission of rotation. The material of the shock-absorbing ring 51 is an elastic material, such as rubber, plastic, etc.

[0050] It should be noted that the cross-section of the shock-absorbing ring 51 can be set in various shapes such as square, circular, hexagonal, etc. In this embodiment, the cross-section of the shock-absorbing ring 51 is square, as Figure 3 shown. Of course, other flexible connection methods can also be used between the power output end of the rotating shaft 50 of the radiation-resistant motor 5 and the magnetohydrodynamic sealing shaft 6, such as replacing the shock-absorbing ring 51 with an elastic coupling to achieve flexible connection between the two.

[0051] The cooling medium cools the tungsten target disk 1 through the cooling assembly 7. The flange sleeve 2 is installed on the magneto-fluid seal shaft 6 and is sealingly connected to the vacuum chamber housing 3. In this embodiment, the flange sleeve 2 is sleeved on the magneto-fluid seal shaft 6, and the magneto-fluid seal shaft 6 rotates relative to the flange sleeve 2 driven by the radiation-resistant motor 5. A magneto-fluid seal is adopted between the flange sleeve 2 and the magneto-fluid seal shaft 6. The flange sleeve 2 is connected to the vacuum chamber housing 3 by bolts, and sealing is achieved by means of a knife-edge seal between the flange sleeve 2 and the vacuum chamber housing 3. More specifically, the flange part of the flange sleeve 2 is connected to the vacuum chamber housing 3 by bolts, and sealing is achieved by means of a knife-edge seal between the flange surface of the flange sleeve 2 and the vacuum chamber housing 3. The magneto-fluid seal and the knife-edge seal isolate the inside and outside of the vacuum chamber housing 3, ensuring that the vacuum environment inside the vacuum chamber housing 3 is not damaged.

[0052] See Figures 1 to 3 , in this embodiment, the cooling assembly 7 includes a rotary joint 71, a water inlet 72, a water outlet 73, and a water inlet pipe 74;

[0053] The rotary joint 71 is installed at the tail of the magneto-fluid seal shaft 6 and is connected to the magneto-fluid seal shaft 6;

[0054] The rotary joint is provided with a water inlet 72 and a water outlet 73. One end of the water inlet pipe 74 is connected and communicated with the water inlet 72, and then the other end passes through the magneto-fluid seal shaft 6 and is communicated with the inlet of the cooling channel on the tungsten target disk 1. The outlet of the cooling channel on the tungsten target disk is communicated with the annular space gap between the water inlet pipe 74 and the magneto-fluid seal shaft 6; the annular space gap between the water inlet pipe 74 and the magneto-fluid seal shaft 6 is communicated with the water outlet of the rotary joint;

[0055] The water inlet and the water outlet are the inlet end and the outlet end of the cooling medium. The tungsten target disk and the water inlet of the rotary joint can rotate relative to the water inlet pipe, and graphite rings are provided at both ends of the water inlet pipe.

[0056] The vacuum inner part of the magneto-fluid seal shaft 6 is welded to the tungsten target disk 1. The magneto-fluid seal shaft 6 is a hollow shaft, and the inside of the hollow shaft is a cooling water path.

[0057] The tungsten target disk 1 is circular, and the cooling channels on the target disk are the same as the target disk circulating water path in a water-cooled rotary radiation conversion target for high-energy microfocus X-rays with the application number: 202110771076.4. The geometric center hole of the tungsten target disk 1 is the water inlet of the cooling channel of the target disk. Cooling water is injected into the water inlet of the cooling channel of the tungsten target disk through the water inlet pipe, circulates through the cooling channel in one of the spokes of the tungsten target disk to the cooling channel on the edge of the tungsten target disk, and finally returns to the water outlet of the cooling channel of the tungsten target disk through the cooling channel in another spoke. The water outlet of the cooling channel of the tungsten target disk is communicated with the annular space gap between the water inlet pipe and the magnetohydrodynamic sealing shaft, and then discharged from the water outlet of the rotary joint to achieve the purpose of cooling the tungsten target disk.

[0058] The water inlet 72 and the water outlet 73 are the water inlet end and the water outlet end of the cooling medium. The tungsten target disk 1, the water inlet 72 and the water inlet pipe 74 can all rotate relative to each other. To prevent wear, graphite rings are also provided at both ends of the water inlet pipe 74.

[0059] For convenient debugging, a beam spot measurement target 8 is installed on the vacuum chamber housing 3. The beam spot measurement target 8 includes a lifting mechanism and a YAG target. The YAG target is installed at the bottom of the lifting mechanism, and the installation direction of the YAG target forms a 45° angle with the incident direction of the electron beam. An observation window 10 for observing the YAG target is also provided on the vacuum chamber housing 3. The position of the observation window 10 is aligned with the YAG target, and the electron beam spot on the YAG target can be viewed.

[0060] The bellows 9 is installed on the vacuum chamber housing 3.

[0061] The magnetic rotary encoder is installed on the radiation-resistant motor 5, and the magnetic Hall switch is installed on the cylindrical surface of the motor mounting seat 4.

[0062] During use, the radiation-resistant motor 5 adopts a hollow shaft structure. The magnetohydrodynamic sealing shaft 6 passes through the radiation-resistant motor 5 and is connected to it through a shock-absorbing ring 51 or an elastic coupling, which can provide good shock absorption and displacement compensation capabilities and achieve smooth power transmission. The radiation-resistant motor 5 drives the magnetohydrodynamic sealing shaft 6 to rotate, and the magnetohydrodynamic sealing shaft 6 drives the tungsten target disk 1 to rotate. After the radiation-resistant motor 5 adopts a hollow shaft structure, it can not only directly connect the motor to drive the rotating target, but also combine the cooling circuit with the hollow shaft of the radiation-resistant motor 5. At the same time, the cooling circuit and the radiation-resistant motor 5 are arranged on the same side, greatly simplifying the structure of the entire rotating target.

[0063] During the use process, the cooling medium, such as cooling water, enters through the water inlet 72, reaches the tungsten target disk 1 after passing through the water inlet pipe 74, circulates on the tungsten target disk 1 and then flows into the annular space gap between the water inlet pipe 74 and the magnetohydrodynamic sealing shaft 6, and finally flows out from the water outlet 73, thereby realizing the circulation of the cooling water path.

[0064] When the tungsten target disk 1 rotates at high speed, the magnetic encoder and the magnetic Hall switch detect the rotation speed of the tungsten target disk 1. By comparing the actual rotation speed with the set rotation speed of the motor in real time, it is possible to determine whether the radiation rotating target is operating at the correct rotation speed and whether the running smoothness meets the set requirements, so as to ensure that the time period for the electron beam to bombard the same position on the tungsten target disk is long enough and the radiation rotating target can operate normally.

[0065] When it is necessary to measure the size of the electron beam spot, the lifting mechanism in the spot measurement target 8 drives the YAG target to move and lower the YAG target so that the electron beam directly irradiates into the YAG target. The installation direction of the YAG target forms an angle of 45° with the incident direction of the electron beam. When the electron beam bombards the YAG target to generate fluorescence, the spot is oval-shaped, and measuring the longitudinal length of the spot can obtain the size of the electron beam spot.

[0066] When measuring the size of the electron beam spot, the observation window 10 can be used to observe the spot measurement.

[0067] Although the present invention has been described herein with reference to illustrative embodiments of the present invention, it should be understood that those skilled in the art can design many other modifications and embodiments that will fall within the scope and spirit of the principles disclosed in this application. More specifically, within the scope of the disclosure of this application, various variations and improvements can be made to the components and / or layout of the subject combination layout. In addition to the variations and improvements made to the components and / or layout, other uses will also be apparent to those skilled in the art.

Claims

1. A coaxial direct-drive rotating radiation conversion target for high-energy X-rays, characterized in that It includes a tungsten target disk, a flange sleeve, a radiation-resistant motor, a magnetohydrodynamic sealing shaft, and a cooling assembly; The radiation-resistant motor adopts a structure with a hollow rotating shaft. One end of the magnetohydrodynamic sealing shaft is fixedly connected to the tungsten target disk, and the other end passes through the rotating shaft of the radiation-resistant motor and is connected to the rotary joint in the cooling assembly; The power output end of the rotating shaft of the radiation-resistant motor is connected to the magnetohydrodynamic sealing shaft; The cooling assembly circulates a cooling medium to cool the tungsten target disk. The flange sleeve is installed on the magnetohydrodynamic sealing shaft and is hermetically connected to the vacuum chamber housing.

2. The coaxial direct-drive rotary radiation conversion target for high-energy X-rays according to claim 1, wherein, The power output end of the rotating shaft of the radiation-resistant motor matches the outer shape of the magnetohydrodynamic sealing shaft, and the power output ends of the rotating shafts of the radiation-resistant motor are flexibly connected.

3. The coaxial direct-drive rotating radiation conversion target for high-energy X-rays according to claim 2, characterized in that, The rotating shaft of the radiation-resistant motor is connected to the magnetohydrodynamic sealing shaft through a shock-absorbing ring, and the shock-absorbing ring is made of an elastic material.

4. The coaxial direct-drive rotating radiation conversion target for high-energy X-rays according to claim 1, wherein The cooling assembly includes a rotary joint and a water inlet pipe; The rotary joint is installed at the tail of the magnetohydrodynamic sealing shaft and is connected to the magnetohydrodynamic sealing shaft; One end of the water inlet pipe is communicated with the water inlet of the rotary joint, and the other end passes through the magnetohydrodynamic sealing shaft and is communicated with the inlet of the cooling channel on the tungsten target disk. The outlet of the cooling channel on the tungsten target disk is communicated with the annular space gap between the water inlet pipe and the magnetohydrodynamic sealing shaft; the annular space gap between the water inlet pipe and the magnetohydrodynamic sealing shaft is communicated with the water outlet of the rotary joint; The tungsten target disk, the water inlet of the rotary joint and the water inlet pipe can all rotate relative to each other, and graphite rings are arranged at both ends of the water inlet pipe.

5. The coaxial direct-drive rotary radiation conversion target for high-energy X-rays according to claim 1, wherein, It also includes a beam spot measurement target; The beam spot measurement target includes a lifting mechanism and a YAG target. The YAG target is installed at the bottom of the lifting mechanism, and the beam spot measurement target is installed on the vacuum chamber housing.

6. The coaxial direct-drive rotating radiation conversion target for high-energy X-rays according to claim 5, characterized in that, The installation direction of the YAG target forms a 45° angle with the incident direction of the electron beam.

7. The high-energy X-ray coaxial direct-drive rotating radiation conversion target according to claim 1, characterized in that: It also includes a bellows; The bellows is installed on the vacuum chamber housing.

8. The coaxial direct-drive rotating radiation conversion target for high-energy X-rays according to claim 5, wherein, It also includes an observation window; The observation window is installed on the vacuum chamber housing, and the position of the observation window is aligned with the YAG target.

9. The coaxial direct-drive rotating radiation conversion target for high-energy X-rays according to claim 1, characterized in that, It also includes a magnetic rotary encoder; The magnetic rotary encoder is installed on the radiation-resistant motor.

10. The coaxial direct-drive rotating radiation conversion target for high-energy X-rays according to claim 1, characterized in that, It also includes a magnetic Hall switch; The magnetic Hall switch is installed on the cylindrical surface of the motor mounting seat.

Images