A square-hole particle beam collimator with continuously adjustable aperture and its aperture adjustment method

Abstract

The present invention discloses a square-hole particle beam collimator with continuously adjustable aperture and its aperture adjustment method. In the collimator, a rotating disk is provided in the collimator main body. The rotating disk is provided with disk through holes and a plurality of arc-shaped guide grooves. A pair of first collimating blocks and a pair of second collimating blocks are respectively provided on both sides of the rotating disk. Contact sleeves are also respectively provided on each collimating block. Each contact sleeve slides along the arc-shaped guide groove when the rotating disk rotates. A linkage assembly connected to the power output end of the aperture adjustment driving mechanism is also provided outside the rotating disk. The aperture adjustment method is that when the rotating disk rotates, each arc-shaped guide groove drives the contact sleeve to move, thereby driving the first collimating block and the second collimating block to perform opening and closing actions respectively. When the channel distance between the two first collimating blocks and the second collimating blocks changes, the aperture of the square hole changes accordingly. This collimator has a compact structure and is convenient to use, and can be preferably applied to the accompanying proton beam of the China Spallation Neutron Source.

Description

Technical Field

[0001] The present invention relates to the technical field of collimators, and particularly to a square-hole particle beam collimator with continuously adjustable aperture and its aperture adjustment method. Background Art

[0002] The associated proton beam experimental device of the China Spallation Neutron Source is a device for particle experiments using proton beams with a certain energy generated by a linear accelerator. During the experiment, negative hydrogen ions generated by the ion source are accelerated to an energy of 80 MeV by an electrostatic field and a radio frequency electric field. During the acceleration or transportation process of the negative hydrogen ions, part of them are transformed into hydrogen atoms and hydrogen ions. At the end of the linear tunnel, the negative hydrogen ions in the particle beam are deflected by a magnetic field into the fast cycling synchrotron; among them, the hydrogen atoms enter the waste beam station; and the hydrogen ions enter the associated proton beam experimental device. Before the hydrogen ion beam reaches the experimental sample, a collimator is usually required to collimate the beam spot of the particle beam and adjust the size of the beam spot, so as to achieve precise irradiation of a specific range and specific position of the sample, while the irradiation amount at other positions in the sample that do not need to be irradiated is extremely small.

[0003] Currently, the collimation of the associated proton beam is coordinated by three collimators. By using the different apertures formed after the combination of the blocks in the three collimators, a beam spot with the required size is obtained at the experimental position. Generally, collimators are designed according to beam characteristics such as particle type, energy, and beam power, and appropriate beam-blocking materials are selected according to relevant characteristics such as the activation situation, service life, and processability of the beam-blocking material, such as copper, iron, graphite, tungsten alloy, lead, boron, and their combinations. Common structural design forms include fixed-aperture collimators, multi-gear fixed-aperture collimators, adjustable-aperture collimators, etc. The conventional design of the adjustable-aperture collimator is to independently configure a motor and a corresponding transmission mechanism on each block, and drive the corresponding block to move independently from all directions by four motors, so as to adjust the aperture formed between the four blocks; however, in actual applications, the collimator of this structural form is relatively large in volume, and a shielding body needs to be arranged on its outer periphery during use, and the required equipment installation space is also large, and the corresponding control system load is also large. Therefore, the adjustable-aperture collimator driven by multiple motors is difficult to be applied in the existing tunnel of the associated proton beam of the China Spallation Neutron Source. At the same time, its equipment energy consumption is high, the equipment structure is complex, and the design of the surrounding shielding body is difficult, which is not conducive to cost control. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a square-hole particle beam collimator with continuously adjustable aperture, which has a compact structure and is convenient to use, and can be better installed and applied in the existing tunnel of the associated proton beam of the China Spallation Neutron Source.

[0005] Another purpose of the present invention is to provide an aperture adjustment method for the above-mentioned square-hole particle beam collimator with continuously adjustable aperture.

[0006] The technical solution of the present invention is as follows: a square-hole particle beam collimator with continuously adjustable aperture, comprising a mounting base, a vacuum chamber, a collimator body and an aperture adjustment driving mechanism. The vacuum chamber is arranged on the mounting base, the collimator body is arranged in the vacuum chamber, and the power output end of the aperture adjustment driving mechanism extends into the vacuum chamber and is connected with the collimator body;

[0007] A rotating disk is arranged in the collimator body. A disk through-hole is arranged in the middle of the rotating disk. A plurality of arc-shaped guide grooves are distributed on the outer periphery of the disk through-hole. A pair of first collimating blocks that perform opening and closing movements are arranged on the outer side of one end face of the rotating disk. A pair of second collimating blocks that perform opening and closing movements are arranged on the outer side of the other end face of the rotating disk. The opening and closing movement directions of the first collimating blocks are perpendicular to the opening and closing movement directions of the second collimating blocks. Contact sleeves are respectively arranged on each first collimating block and each second collimating block. Each contact sleeve is embedded in the arc-shaped guide groove on the rotating disk and slides along the arc-shaped guide groove when the rotating disk rotates; A linkage assembly is also arranged on the outer circumference of the rotating disk, and the linkage assembly is connected with the power output end of the aperture adjustment driving mechanism.

[0008] In the above collimator body structure, a channel with a certain distance is left between the two first collimating blocks, and a channel with a certain distance is also left between the two second collimating blocks. These two channels are perpendicular to each other and are respectively located on both sides of the disk through-hole of the rotating disk. By blocking part of the position of the disk through-hole by the first collimating blocks and the second collimating blocks, a square-hole channel is formed within the range of the disk through-hole. When adjusting the square-hole aperture, the aperture adjustment driving mechanism arranged outside the collimator body provides power, drives the rotating disk to rotate through the linkage assembly. During the rotation of the rotating disk, the guiding action of the arc-shaped guide groove is used to drive the two first collimating blocks and the two second collimating blocks to perform opening and closing actions simultaneously, so as to adjust the width of each channel simultaneously, and change the aperture of the square hole formed between the two channels and the disk through-hole; When the graphite blocking blocks of each pair of collimating blocks (i.e., the first collimating blocks or the second collimating blocks) approach or move away from each other, the aperture of the square hole at their center correspondingly decreases or increases, so as to achieve continuous adjustment of the collimation aperture and play a collimation adjustment role on the beam spot size of the beam. The gap distances (i.e., the widths of the above two channels) when each pair of collimating blocks (i.e., the first collimating blocks or the second collimating blocks) are opened are the same, so a square hole can be formed. The two collimating blocks in each pair of collimating blocks can also be in complete contact with each other to achieve the closing effect. At this time, it can be used as a beam switch; The gap between the two collimating blocks can also be made very small to form a collimation hole with a very small aperture. In the actual application process, an external control system can be further used to precisely control the actions of the aperture adjustment driving mechanism and the gap distances between the first collimating blocks and the second collimating blocks.

[0009] In the collimator body, a first guide rail fixing plate and a second guide rail fixing plate are respectively arranged on the outer sides of the two end faces of the rotating disk;

[0010] Two first guide rails are installed on the first guide rail fixing plate and are distributed in parallel. First sliders are respectively arranged at both ends of each first collimator block, and both ends of each first collimator block are respectively installed on the first guide rails through the first sliders. The two first collimator blocks are symmetrically arranged. The first guide rails provide a guiding function for the movement of the first collimator blocks, making the operation of the two first collimator blocks stable and reliable, and better ensuring the accuracy of the square hole aperture adjustment.

[0011] Two second guide rails are installed on the second guide rail fixing plate and are distributed in parallel. Second sliders are respectively arranged at both ends of each second collimator block, and both ends of each second collimator block are respectively installed on the second guide rails through the second sliders. The two second collimator blocks are symmetrically arranged. The second guide rails provide a guiding function for the movement of the second collimator blocks, making the operation of the two second collimator blocks stable and reliable, and better ensuring the accuracy of the square hole aperture adjustment.

[0012] At least one arc guide rail is further installed on the second guide rail fixing plate. The arc guide rail is configured with a third slider. An extension part is arranged on the end face of the rotating disc facing the second fixing plate, and the extension part is fixedly connected to the third slider. When the rotating disc rotates, it makes a rotational movement around the rotation center of the arc guide rail through the third slider, and has a single-direction degree of freedom, and its operation accuracy is relatively high. In order to further improve the stability of the rotating disc during movement, two symmetric arc guide rails can be arranged on the second fixing plate, and the radian of each arc guide rail is adapted to the circumferential direction of the rotating disc.

[0013] Fixing plate through holes are respectively arranged in the middle parts of the first guide rail fixing plate and the second guide rail fixing plate. Each fixing plate through hole is coaxially arranged with the disc through hole. The channels between the two first collimator blocks and the channels between the two second collimator blocks intersect to form a square hole coaxially with the disc through hole.

[0014] A fixed connection block is further arranged on the outer periphery of the rotating disc. The first guide rail fixing plate and the second guide rail fixing plate are respectively installed on the fixed connection block. The linkage assembly passes through the through holes on the side of the fixed connection block. In this structure, the fixed connection block mainly serves as the installation base for other components, and can improve the stability of the overall structure after installation.

[0015] In the collimator body, the first collimator block is a collimator block moving in the horizontal direction. Along the horizontal direction, the moving directions of the two first collimator blocks are opposite; the second collimator block is a collimator block moving in the vertical direction. Along the vertical direction, the moving directions of the two second collimator blocks are opposite.

[0016] In the collimator body, the structures of a single first collimating block and a single second collimating block are the same, and each includes an aluminum alloy frame, a graphite stopper, a contact sleeve, and a contact sleeve support rod. The graphite stopper is installed inside the aluminum alloy frame. One side of the aluminum alloy frame is provided with a convex portion, and the contact sleeve is installed on the convex portion through the contact sleeve support rod. Among them, the aluminum alloy frame and the graphite stopper are the main structures of the collimating block (including the first collimating block and the second collimating block). The contact sleeve support rod is installed on the aluminum alloy frame, and the two are locked to each other. The contact sleeve is installed on the contact sleeve support rod and the contact sleeve can rotate relative to the contact sleeve support rod; when the graphite stoppers of each pair of collimating blocks (i.e., the first collimating block or the second collimating block) approach or move away from each other, the aperture of the square hole in the center thereof correspondingly decreases or increases, so as to achieve continuous adjustment of the collimation aperture and play a collimation adjustment role on the beam spot size.

[0017] In the collimator body, the linkage assembly includes a linkage curved rod and a double hinge. One end of the linkage curved rod is arranged on the rotating disk, and the other end of the linkage curved rod is provided with a double hinge; the power output end of the aperture adjustment driving mechanism is a pull rod, and the end of the pull rod is connected to the double hinge.

[0018] The aperture adjustment driving mechanism includes a bracket, a linear motion assembly, and a bellows vacuum transmission assembly. The linear motion assembly and the bellows vacuum transmission assembly are respectively installed on the bracket, and the power output end of the linear motion assembly is connected to the bellows vacuum transmission assembly.

[0019] The linear motion assembly includes a driving motor, a coupling, a lead screw, a nut, a linear motion block, a linear motion guide rail, and a linear motion slider. The output shaft end of the driving motor is connected to the lead screw through the coupling. The lead screw is provided with a nut, and the linear motion block is fixedly installed on the nut; at least one linear motion guide rail parallel to the lead screw is further provided on the bracket, and a linear motion slider is arranged on the linear motion guide rail. The linear motion block is also fixedly connected to the linear motion slider; during the equipment assembly process, the output shaft of the driving motor, the coupling, and the lead screw form a linear power output structure vertically downward. The two ends of the lead screw can be respectively fixedly installed on the bracket through bearing seats, and the driving motor is also fixedly installed on the bracket; among them, as a preferred method, the driving motor can adopt a stepping motor, the lead screw can adopt a trapezoidal lead screw, and the nut also correspondingly adopts a trapezoidal nut; further, a limit switch (a general-purpose limit switch on the market can be used) can also be set on the bracket. The limit switch is used for motion limit and also serves as the origin of the linear motion of the linear motion block, so as to further improve the aperture adjustment accuracy in the collimator body.

[0020] The corrugated tube vacuum drive assembly includes a corrugated tube, a pull rod, and a flange. The upper end of the pull rod is fixedly connected to the linear motion block. After the lower end of the pull rod extends into the vacuum cavity, it is connected to the linkage assembly on the rotating disk. A corrugated tube is sleeved on the outer periphery of the pull rod. The upper end of the corrugated tube is fixedly connected to the linear motion block. The lower end of the corrugated tube is provided with a flange and is fixedly installed on the vacuum cavity through the flange. Among them, the corrugated tube is of a telescopic structure. When the linear motion assembly drives the linear motion block to perform a lifting motion, the pull rod will follow and perform a lifting motion. At this time, the lower end of the pull rod will drive the linkage assembly to swing, thereby driving the rotating disk to rotate. During this process, the corrugated tube adapts to the lifting motion of the pull rod through its own telescopic motion.

[0021] In the above-mentioned square-hole particle beam collimator, the mounting base and the vacuum cavity can both adopt the mounting base and the vacuum cavity with the same structure as the existing collimator.

[0022] A method for adjusting the aperture of the above-mentioned square-hole particle beam collimator with continuously adjustable aperture is specifically as follows: When it is necessary to adjust the aperture of the square hole in the collimator body, start the aperture adjustment drive mechanism and output power. Drive the rotating disk to rotate through the linkage assembly. The arc-shaped guide grooves on the rotating disk will follow and rotate, driving each contact sleeve to move in the direction close to or away from the center of the rotating disk, thereby driving the two first collimating blocks and the two second collimating blocks to perform opening and closing actions simultaneously. When the channel distance between the two first collimating blocks and the channel distance between the two second collimating blocks change, the aperture of the square hole formed inside the collimator body will change accordingly, thereby realizing the adjustment of the square hole aperture.

[0023] When the above-mentioned square-hole particle beam collimator with continuously adjustable aperture and its aperture adjustment method are applied, the principle is as follows: When it is necessary to adjust the aperture of the square hole in the collimator body, start the drive motor in the aperture adjustment drive mechanism. After the drive motor outputs power, it is transmitted to the lead screw through the coupling, driving the lead screw to rotate. At this time, the nut drives the linear motion block to move up and down along with the lead screw. In this process, the linear motion slider and the linear motion guide rail cooperate to play a stable guiding role; as the linear motion block moves up and down, the pull rod also follows to produce corresponding up and down movements. In this process, the bellows expands and contracts accordingly. The end of the pull rod drives the linkage crank to swing through the double hinge, thereby driving the rotating disc in the collimator body to rotate. During the rotation of the rotating disc, the guiding action of the arc-shaped guide groove is used to drive the two first collimating blocks and the two second collimating blocks to perform opening and closing actions simultaneously, so as to adjust the width of each channel at the same time, causing the aperture of the square hole formed between the two channels and the through hole of the disc to change; when each pair of collimating blocks (i.e., the first collimating block or the second collimating block) approaches or moves away from each other, the aperture of the square hole in the center thereof correspondingly decreases or increases, so as to achieve continuous adjustment of the collimation aperture and play a collimation adjustment role on the beam spot size; among them, the gap distance (i.e., the width of the above two channels) when each pair of collimating blocks (i.e., the first collimating block or the second collimating block) is opened is the same, so a square hole can be formed, and the two collimating blocks in each pair of collimating blocks can also be in full contact with each other to achieve the closing effect. At this time, it can be used as a beam switch; it is also possible to make the gap between the two collimating blocks very small to form a collimation hole with a very small aperture.

[0024] The present invention has the following beneficial effects compared with the prior art:

[0025] In the square-hole particle beam collimator with continuously adjustable aperture and its aperture adjustment method of the present invention, by arranging a rotating disc with an arc-shaped guide groove between two pairs of collimating blocks, the rotation of the rotating disc is driven by a unified aperture adjustment drive mechanism to realize the gap adjustment between the two pairs of collimating blocks, thereby realizing the continuous adjustment of the aperture of the square hole in the collimator body. That is, by using a single drive motor to simultaneously control the four-direction movements of the two pairs of collimating blocks and form a square collimation hole, the number of drive mechanisms used can be greatly reduced, the manufacturing cost of the equipment can be reduced, the overall volume of the equipment can be reduced, the overall structure of the equipment can be made more compact, the external space can be saved, and the design and construction of the external shielding body can be facilitated. It can be better installed and applied in the existing tunnel of the associated proton beam of the China Spallation Neutron Source; at the same time, since the same aperture adjustment drive mechanism is used as the power mechanism for aperture adjustment, the adjustment accuracy of the aperture of the square hole in the collimator can be better guaranteed.

[0026] In the square-hole particle beam collimator with continuously adjustable aperture of the present invention, the two pairs of collimating blocks are respectively matched with two groups of guide rails and guide rail fixing plates arranged on both sides of the rotating disc to form two relatively independent mechanisms, which is convenient for equipment debugging or maintenance.

[0027] In this square-hole particle beam collimator with continuously adjustable aperture, the aperture adjustment driving mechanism is arranged outside the collimator main body and its vacuum chamber, and then the power is transmitted to the inside of the vacuum chamber through the connection of the bellows with the vacuum chamber. On the premise of effectively ensuring the vacuum degree of the equipment, it greatly facilitates the installation, maintenance and other operations of the aperture adjustment driving mechanism. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the overall structure of the split square-hole particle beam collimator.

[0029] Figure 2 is Figure 1 A schematic diagram of the structure of the split collimator main body in

[0030] Figure 3 is Figure 2 A schematic diagram of the structure of a single collimation block (i.e., the first collimation block or the second collimation block) split in

[0031] Figure 4 is Figure 2 A schematic diagram of the principle of the installation of the rotating disk, the second collimation block and the second guide rail fixing plate in

[0032] Figure 5 It is a schematic diagram of the structure of the linear motion component in the aperture adjustment driving mechanism.

[0033] Figure 6 It is a schematic diagram of the structure of the bellows vacuum transmission component in the aperture adjustment driving mechanism.

[0034] In the above figures, the components indicated by each reference numeral are as follows: 1 is the mounting base, 2 is the vacuum chamber, 2-1 is the chamber body, 2-2 is the chamber cover plate, 3 is the collimator body, 4 is the aperture adjustment drive mechanism, 5 is the rotating disk, 5-1 is the disk through-hole, 5-2 is the arc-shaped guide groove, 6 is the first collimating block, 7 is the second collimating block, 8 is the contact sleeve, 9 is the linkage curved rod, 10 is the double hinge, 11 is the fixed connection block, 12 is the first guide rail fixing plate, 13 is the second guide rail fixing plate, 14 is the first guide rail, 15 is the first slider, 16 is the second guide rail, 17 is the second slider, 18 is the arc-shaped guide rail, 19 is the third slider, 20 is the extension part, 21 is the fixing plate through-hole, 22 is the aluminum alloy frame, 22-1 is the convex part, 23 is the graphite stop block, 24 is the contact sleeve support rod, 25 is the nut, 26 is the bracket, 27 is the linear motion component, 28 is the bellows vacuum transmission component, 29 is the drive motor, 30 is the coupling, 31 is the lead screw, 32 is the nut, 33 is the linear motion block, 34 is the linear motion guide rail, 35 is the linear motion slider, 36 is the bellows, 37 is the pull rod, 38 is the flange, 39 is the limit switch, 40 is the KF flange, 41 is the graphite pressing block. a is the power output end of the aperture adjustment drive mechanism. Detailed implementation mode

[0035] The following is a further detailed description of the present invention in conjunction with embodiments, but the implementation modes of the present invention are not limited thereto.

[0036] Embodiment

[0037] In this embodiment, a square-hole particle beam collimator with continuously adjustable aperture has an overall structure as Figure 1 shown, including a mounting base 1, a vacuum chamber 2 (mainly composed of a cooperating chamber body 2-1 and a chamber cover plate 2-2), a collimator body 3, and an aperture adjustment drive mechanism 4. The vacuum chamber is arranged on the mounting base, the collimator body is arranged in the vacuum chamber, and the power output end a of the aperture adjustment drive mechanism extends into the vacuum chamber and is connected to the collimator body. The specific structures of the main mechanisms are as follows:

[0038] As Figure 2The specific structure of the collimator body is shown as follows: A rotating disk 5 is provided in the collimator body. A disk through-hole 5-1 is provided in the middle of the rotating disk. A number of arc-shaped guide grooves 5-2 (four in this embodiment, corresponding to the number of collimating blocks) are distributed on the outer periphery of the disk through-hole. A pair of first collimating blocks 6 that perform an opening and closing movement are provided on the outer side of one end face of the rotating disk. A pair of second collimating blocks 7 that perform an opening and closing movement are provided on the outer side of the other end face of the rotating disk. The opening and closing movement direction of the first collimating blocks is perpendicular to the opening and closing movement direction of the second collimating blocks. Contact sleeves 8 are respectively provided on each of the first collimating blocks and each of the second collimating blocks. Each contact sleeve is embedded in the arc-shaped guide groove on the rotating disk and slides along the arc-shaped guide groove when the rotating disk rotates. A linkage assembly is further provided on the outer circumference of the rotating disk. The linkage assembly is connected to the power output end of the aperture adjustment drive mechanism. The linkage assembly includes a linkage crank 9 and a double hinge 10. One end of the linkage crank is provided on the rotating disk, and the other end of the linkage crank is provided with a double hinge. The power output end of the aperture adjustment drive mechanism is a pull rod (such as Figure 6As shown in the figure, the end of the pull rod is connected to the double hinge. A fixed connection block 11 is also provided on the outer periphery of the rotating disc. The following first guide rail fixing plate and second guide rail fixing plate are respectively installed on the fixed connection block, and the linkage assembly is also installed on the fixed connection block. In this structure, the fixed connection block mainly serves as the installation base for other components, which can improve the stability of the overall structure after installation. In the collimator body, a first guide rail fixing plate 12 and a second guide rail fixing plate 13 are respectively provided on the outer sides of the two end faces of the rotating disc; two first guide rails 14 are installed in parallel on the first guide rail fixing plate. First sliders 15 are provided at both ends of each first collimating block, and both ends of each first collimating block are respectively installed on the first guide rail through the first sliders. The two first collimating blocks are symmetrically arranged; the first guide rail is used to provide a guiding function for the movement of the first collimating block, so that the operation of the two first collimating blocks is stable and reliable, and the accuracy of the square hole aperture adjustment can be better guaranteed; two second guide rails 16 are installed in parallel on the second guide rail fixing plate. Second sliders 17 are provided at both ends of each second collimating block, and both ends of each second collimating block are respectively installed on the second guide rail through the second sliders. The two second collimating blocks are symmetrically arranged; the second guide rail is used to provide a guiding function for the movement of the second collimating block, so that the operation of the two second collimating blocks is stable and reliable, and the accuracy of the square hole aperture adjustment can be better guaranteed. In addition, at least one arc guide rail 18 is also installed on the second guide rail fixing plate. The arc guide rail is provided with a third slider 19. An extension 20 is provided on the end face of the rotating disc facing the second fixing plate. The extension is fixedly connected to the third slider. When the rotating disc rotates, the third slider makes a rotational motion around the rotation center of the arc guide rail, with a single-degree-of-freedom in one direction and relatively high operating accuracy; in this embodiment, in order to further improve the stability of the rotating disc during movement, two symmetric arc guide rails are provided on the second fixing plate. The radian of each arc guide rail is adapted to the circumferential direction of the rotating disc. The two arc guide rails are arranged at the upper and lower ends of the two second guide rails, and both ends of each arc guide rail are respectively connected to the ends of the two second guide rails, so as to avoid interference between the movement of the rotating disc and the movement of the second collimating block during adjustment. Fixing plate through holes 21 are respectively provided in the middle of the first guide rail fixing plate and the second guide rail fixing plate. Each fixing plate through hole is coaxially arranged with the disc through hole. The channels between the two first collimating blocks and the channels between the two second collimating blocks intersect to form a square hole coaxially arranged with the disc through hole. In this embodiment, the first collimating block is a collimating block that moves in the horizontal direction. Along the horizontal direction, the movement directions of the two first collimating blocks are opposite; the second collimating block is a collimating block that moves in the vertical direction. Along the vertical direction, the movement directions of the two second collimating blocks are opposite.

[0039] Among them, the structures of a single first collimating block and a single second collimating block are the same, such as Figure 3As shown in the figure, it respectively includes an aluminum alloy frame 22, a graphite block 23, a contact sleeve 8 and a contact sleeve support rod 24. The graphite block is installed inside the aluminum alloy frame. One side of the aluminum alloy frame is provided with a convex part. The contact sleeve is installed on the convex part 22-1 through the contact sleeve support rod. The end of the contact sleeve support rod is locked and fixed on the convex part through a nut 25. The periphery of the graphite block can be tightly fixed inside the aluminum alloy frame by a plurality of graphite pressing blocks 41 in cooperation with screws or bolts. Among them, the aluminum alloy frame and the graphite block are the main structures of the collimator block (including the first collimator block and the second collimator block). The contact sleeve support rod is installed on the aluminum alloy frame, and the two are locked with each other. The contact sleeve is installed on the contact sleeve support rod and the contact sleeve can rotate relative to the contact sleeve support rod; when the graphite blocks of each pair of collimator blocks (i.e., the first collimator block or the second collimator block) approach or move away from each other, the aperture of the square hole in the center thereof correspondingly decreases or increases, so as to achieve continuous adjustment of the collimation aperture and play a collimation adjustment role on the beam spot size.

[0040] In the above-mentioned collimator main structure, there is a channel with a certain distance between the two first collimator blocks, and there is also a channel with a certain distance between the two second collimator blocks. These two channels are perpendicular to each other and are respectively located on both sides of the disk through-hole of the rotating disk. By blocking part of the position of the disk through-hole by the first collimator block and the second collimator block, a square hole is formed between the two channels and the disk through-hole. When adjusting the aperture of the square hole, the aperture adjustment drive mechanism arranged outside the collimator main body provides power, and drives the rotating disk to rotate through the linkage assembly. During the rotation of the rotating disk, the two first collimator blocks and the two second collimator blocks are driven to perform opening and closing actions simultaneously by the guiding action of the arc-shaped guide groove (as Figure 4 shown), so as to adjust the width of each channel simultaneously, and change the aperture of the square hole formed between the two channels and the disk through-hole; when the graphite blocks of each pair of collimator blocks (i.e., the first collimator block or the second collimator block) approach or move away from each other, the aperture of the square hole in the center thereof correspondingly decreases or increases, so as to achieve continuous adjustment of the collimation aperture and play a collimation adjustment role on the beam spot size. The gap distance (i.e., the width of the above two channels) when each pair of collimator blocks (i.e., the first collimator block or the second collimator block) is opened is the same, so a square hole can be formed, and the two collimator blocks in each pair of collimator blocks can also be in full contact with each other to achieve the closing effect. At this time, it can be used as a beam switch; or the gap between the two collimator blocks can be made very small to form a collimation hole with a very small aperture. In the actual application process, the action and adjustment range of the aperture adjustment drive mechanism can be accurately controlled by further using an external control system.

[0041] As Figure 1As shown, the aperture adjustment drive mechanism includes a bracket 26, a linear motion assembly 27, and a bellows vacuum drive assembly 28. The linear motion assembly and the bellows vacuum drive assembly are respectively installed on the bracket, and the power output end of the linear motion assembly is connected to the bellows vacuum drive assembly. Among them, as Figure 5 shown, the linear motion assembly includes a drive motor 29, a coupling 30, a lead screw 31, a nut 32, a linear motion block 33, a linear motion guide rail 34, and a linear motion slider 35. The output shaft end of the drive motor is connected to the lead screw through the coupling. A nut is provided on the lead screw, and a linear motion block is fixedly installed on the nut. At least one linear motion guide rail parallel to the lead screw is also provided on the bracket. A linear motion slider is configured on the linear motion guide rail, and the linear motion block is also fixedly connected to the linear motion slider. During the equipment assembly process, the output shaft of the drive motor, the coupling, and the lead screw form a linear power output structure vertically downward. The two ends of the lead screw can be respectively fixedly installed on the bracket through bearing seats, and the drive motor is also fixedly installed on the bracket. Among them, as a preferred method, the drive motor can adopt a stepping motor, the lead screw can adopt a trapezoidal lead screw, and the nut also correspondingly adopts a trapezoidal nut. Further, a limit switch 39 (a commonly used limit switch on the market can be used) can also be set on the bracket to accurately control the movement stroke of the drive motor and the lead screw through the limit switch, thereby further improving the aperture adjustment accuracy in the collimator body. As Figure 6 shown, the bellows vacuum drive assembly includes a bellows 36, a pull rod 37, and a flange 38. The upper end of the pull rod is fixedly connected to the linear motion block. After the lower end of the pull rod extends into the vacuum cavity, it is connected to the linkage assembly on the rotating disc. A bellows is sleeved on the outer periphery of the pull rod. The upper end of the bellows is fixedly connected to the linear motion block, and the lower end of the bellows is provided with a flange and is fixedly installed on the vacuum cavity through the flange. Among them, the bellows is a telescopic structure. When the linear motion assembly drives the linear motion block to perform a lifting motion, the pull rod will follow to perform a lifting motion. At this time, the lower end of the pull rod will drive the linkage assembly to swing, thereby driving the rotating disc to rotate. During this process, the bellows adapts to the lifting motion of the pull rod through its own telescopic motion.

[0042] In addition, in the above square-hole particle beam collimator, the installation base and the vacuum cavity can adopt the installation base and the vacuum cavity with the same structure as the existing collimator. Among them, the cavity body and the cavity cover plate that make up the vacuum cavity can be made of aluminum alloy or stainless steel. The two are locked and connected by bolts and sealed with indium wire. KF flanges 40 are respectively arranged on both sides of the vacuum cavity (as Figure 1 shown). The flanges are connected to the vacuum tubes upstream and downstream of them, and the inside is kept in a high-vacuum state. The center of the flange is connected to the square hole formed in the above collimator body. During actual construction and application, four target seats can be set on the top of the vacuum cavity for collimator alignment and calibration.

[0043] The aperture adjustment method of the above-mentioned square-hole particle beam collimator with continuously adjustable aperture is as follows: when it is necessary to adjust the aperture of the square hole in the collimator body, start the aperture adjustment drive mechanism and output power. Drive the rotating disk to rotate through the linkage assembly. The arc-shaped guide grooves on the rotating disk follow to rotate, driving each contact sleeve to move towards or away from the center of the rotating disk, thereby driving the two first collimating blocks and the two second collimating blocks to perform opening and closing actions simultaneously; when the channel distance between the two first collimating blocks and the channel distance between the two second collimating blocks change, the aperture of the square hole formed inside the collimator body follows to change, thus realizing the adjustment of the square-hole aperture.

[0044] When the above-mentioned square-hole particle beam collimator with continuously adjustable aperture and its aperture adjustment method are applied, the principle is as follows: when it is necessary to adjust the aperture of the square hole in the collimator body, start the drive motor in the aperture adjustment drive mechanism. After the drive motor outputs power, it is transmitted to the lead screw through the coupling, driving the lead screw to rotate. At this time, the nut drives the linear motion block to move up and down following the lead screw. During this process, the linear motion slider and the linear motion guide rail cooperate to play a stable guiding role; as the linear motion block moves up and down, the pull rod also follows to produce corresponding up and down movements. During this process, the bellows expands and contracts accordingly. The end of the pull rod drives the linkage curved rod to swing through the two-way hinge, thereby driving the rotating disk in the collimator body to rotate. During the rotation of the rotating disk, the guiding effect of the arc-shaped guide groove is used to drive the two first collimating blocks and the two second collimating blocks to perform opening and closing actions simultaneously, thereby adjusting the width of each channel at the same time, causing the aperture of the square hole formed between the two channels and the disk through-hole to change; when each pair of collimating blocks (i.e., the first collimating block or the second collimating block) approaches or moves away from each other, the aperture of the square hole at its center correspondingly decreases or increases, thus achieving continuous adjustment of the collimation aperture and playing a collimation adjustment role on the beam spot size of the beam; among them, the gap distance (i.e., the width of the above two channels) when each pair of collimating blocks (i.e., the first collimating block or the second collimating block) is opened is the same, so a square hole can be formed, and the two collimating blocks in each pair of collimating blocks can also be in full contact with each other to achieve the closing effect. At this time, it can be used as a beam switch; it is also possible to make the gap between the two collimating blocks very small to form a collimation hole with a very small aperture.

[0045] As described above, the present invention can be preferably realized. The above embodiments are only the preferred embodiments of the present invention and are not used to limit the scope of implementation of the present invention; that is, all equivalent changes and modifications made according to the content of the present invention are covered by the scope protected by the claims of the present invention.

Claims

1. A square-hole particle beam collimator with continuously adjustable aperture, characterized in that, It includes an installation base, a vacuum chamber, a collimator body, and an aperture adjustment drive mechanism. The vacuum chamber is arranged on the installation base, the collimator body is arranged inside the vacuum chamber, and the power output end of the aperture adjustment drive mechanism extends into the vacuum chamber and is connected to the collimator body; A rotating disk is provided in the collimator body. A disk through-hole is provided in the middle of the rotating disk. A number of arc-shaped guide grooves are distributed on the outer periphery of the disk through-hole. A pair of first collimating blocks that perform opening and closing movements are provided on the outer side of one end face of the rotating disk. A pair of second collimating blocks that perform opening and closing movements are provided on the outer side of the other end face of the rotating disk. The opening and closing movement directions of the first collimating blocks are perpendicular to the opening and closing movement directions of the second collimating blocks. Contact sleeves are respectively provided on each of the first collimating blocks and each of the second collimating blocks. Each contact sleeve is embedded in the arc-shaped guide groove on the rotating disk and slides along the arc-shaped guide groove when the rotating disk rotates; A linkage assembly is further provided on the outer circumference of the rotating disk, and the linkage assembly is connected to the power output end of the aperture adjustment drive mechanism; In the collimator body, a first guide rail fixing plate and a second guide rail fixing plate are respectively provided on the outer sides of the two end faces of the rotating disk; Two first guide rails are installed in parallel on the first guide rail fixing plate. First sliders are respectively provided at both ends of each first collimating block, and both ends of each first collimating block are respectively installed on the first guide rails through the first sliders. The two first collimating blocks are symmetrically arranged; Two second guide rails are installed in parallel on the second guide rail fixing plate. Second sliders are respectively provided at both ends of each second collimating block, and both ends of each second collimating block are respectively installed on the second guide rails through the second sliders. The two second collimating blocks are symmetrically arranged; At least one arc-shaped guide rail is further installed on the second guide rail fixing plate. The arc-shaped guide rail is configured with a third slider. An extension part is provided on the end face of the rotating disk facing the second fixing plate, and the extension part is fixedly connected to the third slider; The aperture adjustment drive mechanism includes a bracket, a linear motion assembly, and a bellows vacuum transmission assembly. The linear motion assembly and the bellows vacuum transmission assembly are respectively installed on the bracket, and the power output end of the linear motion assembly is connected to the bellows vacuum transmission assembly; The linear motion assembly includes a drive motor, a coupling, a lead screw, a nut, a linear motion block, a linear motion guide rail, and a linear motion slider. The output shaft end of the drive motor is connected to the lead screw through the coupling. A nut is provided on the lead screw, and a linear motion block is fixedly installed on the nut; At least one linear motion guide rail parallel to the lead screw is further provided on the bracket. The linear motion guide rail is configured with a linear motion slider, and the linear motion block is also fixedly connected to the linear motion slider; The bellows vacuum transmission assembly includes a bellows, a pull rod, and a flange. The upper end of the pull rod is fixedly connected to the linear motion block. After the lower end of the pull rod extends into the vacuum chamber, it is connected to the linkage assembly on the rotating disk. The bellows is sleeved on the outer periphery of the pull rod. The upper end of the bellows is fixedly connected to the linear motion block. The lower end of the bellows is provided with a flange and is fixedly installed on the vacuum chamber through the flange.

2. The square-hole particle beam collimator with continuously adjustable aperture according to claim 1, wherein The middle parts of the first guide rail fixing plate and the second guide rail fixing plate are respectively provided with fixing plate through holes, and each fixing plate through hole is coaxially arranged with the disk through hole. The channels between the two first collimator blocks and the channels between the two second collimator blocks intersect to form a square hole coaxially arranged with the disk through hole.

3. The square-hole particle beam collimator with continuously adjustable aperture according to claim 1, wherein A fixed connection block is further provided on the outer periphery of the rotating disk. The first guide rail fixing plate and the second guide rail fixing plate are respectively installed on the fixed connection block, and the linkage assembly passes through the through hole on the side of the fixed connection block.

4. The square-hole particle beam collimator with continuously adjustable aperture according to claim 1, characterized in that, In the collimator body, the first collimator block is a collimator block moving in the horizontal direction. Along the horizontal direction, the moving directions of the two first collimator blocks are opposite; the second collimator block is a collimator block moving in the vertical direction. Along the vertical direction, the moving directions of the two second collimator blocks are opposite.

5. The square-hole particle beam collimator with continuously adjustable aperture according to claim 1, wherein In the collimator body, the structure of a single first collimator block and a single second collimator block is the same, and each includes an aluminum alloy frame, a graphite stopper, a contact sleeve, and a contact sleeve support rod. The graphite stopper is installed in the aluminum alloy frame. A convex part is provided on one side of the aluminum alloy frame, and the contact sleeve is installed on the convex part through the contact sleeve support rod.

6. The square-hole particle beam collimator with continuously adjustable aperture according to claim 1, wherein In the collimator body, the linkage assembly includes a linkage curved rod and a double hinge. One end of the linkage curved rod is arranged on the rotating disk, and the other end of the linkage curved rod is provided with a double hinge; the power output end of the aperture adjustment driving mechanism is a pull rod, and the end of the pull rod is connected to the double hinge.

7. The aperture adjustment method of a square-hole particle beam collimator with continuously adjustable aperture according to any one of claims 1 to 6, characterized in that When it is necessary to adjust the aperture of the square hole in the collimator body, start the aperture adjustment driving mechanism and output power. Drive the rotating disk to rotate through the linkage assembly. The arc-shaped guide grooves on the rotating disk follow to rotate, driving each contact sleeve to move towards or away from the center of the rotating disk, so as to drive the two first collimator blocks and the two second collimator blocks to perform opening and closing actions simultaneously; when the channel distance between the two first collimator blocks and the channel distance between the two second collimator blocks change, the aperture of the square hole formed inside the collimator body follows to change, thereby realizing the adjustment of the square hole aperture.

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