A magnetic field measurement device for a cyclotron

Abstract

The present invention relates to a magnetic field measurement device for a cyclotron, comprising: an outer shaft, an inner shaft sleeved inside the outer shaft, a measuring arm, a radial measuring mechanism and a circumferential measuring mechanism mounted on the measuring arm, a first driving mechanism and a second driving mechanism; the top end of the outer shaft is fixedly connected to the radial measuring arm, the inner shaft is sleeved inside the outer shaft, and the top end thereof extends out from the top end of the outer shaft, and the top end of the inner shaft is connected to the radial measuring mechanism on the measuring arm; the output end of the first driving mechanism is connected to the bottom end of the outer shaft and is used for driving the outer shaft to rotate, and the rotation of the outer shaft drives the circumferential measuring mechanism to rotate; the output end of the second driving mechanism is connected to the bottom end of the inner shaft, and the measuring mechanism is used for measuring the magnetic field intensity. The cyclotron magnetic field measurement device has a compact structure and can more accurately measure the magnetic field intensity at various positions along the radial and circumferential directions.

Description

Technical Field

[0001] The present invention relates to the field of cyclotrons, and particularly to a magnetic field measuring device for a cyclotron. Background Art

[0002] A cyclotron is a device that uses magnetic and electric fields to make charged particles move in a circular motion and repeatedly accelerates them through a high-frequency electric field during the motion. The gap between the upper and lower pole heads that form the magnetic field in the cyclotron is relatively small, and it is a relatively enclosed space. Only the central hole and the side hole can lead to the pole head air gap. The cyclotron is designed for an isochronous magnetic field, with a relatively high magnetic field strength, and it is necessary to measure the magnetic field within the entire pole face range, requiring relatively high precision for magnetic field measurement and positioning.

[0003] In the existing magnetic field measurement platform, the angular and radial power transmissions are respectively carried out through two transmission paths, namely through the central hole and the side hole of the magnet, which increases the installation difficulty and precision. Moreover, its angular transmission uses a synchronous belt drive, and the synchronous belt will slip during use, resulting in discontinuous measurement processes and affecting the measurement precision.

[0004] In addition, the angular rotation of the existing magnetic field measurement platform uses a stepping motor to reduce the rotation speed through a gearbox, and an encoder is used to cooperate with the stepping motor for closed-loop operation. However, it is only limited to using the encoder to locate the circumferential position, and its radial positioning requires manual cooperation with a tracker for adjustment, with relatively poor positioning precision. At the same time, the adjustment range of the Hall probe position is relatively small, and it is difficult to adjust it to the mid-plane of the cyclotron. Moreover, the central drive shaft of this device needs to be adjusted manually by padding to adjust its concentricity with the cyclotron, which is time-consuming and laborious. This device has a bulky structure and cannot continuously and accurately measure the magnetic field. Summary of the Invention

[0005] Aiming at the above problems, the purpose of the present invention is to provide a magnetic field measuring device for a cyclotron, which is more compact and lighter, and can ensure the installation precision on the cyclotron through the precision of the magnetic field measuring device itself, reducing the manual precision adjustment during the installation process.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A magnetic field measuring device for a cyclotron, comprising:

[0008] An outer shaft and an inner shaft, which are coaxially sleeved, and both ends of the inner shaft extend out of the outer shaft;

[0009] A measuring arm, connected to the top end of the outer shaft;

[0010] A measuring mechanism is installed on the measuring arm, and the measuring mechanism is connected to the top end of the inner shaft. The measuring mechanism is configured to measure the magnetic field strength at various positions within the magnetic field pole face of the cyclotron.

[0011] A first driving mechanism, the output end of the first driving mechanism is connected to the bottom end of the outer shaft. The first driving mechanism is configured to drive the outer shaft to rotate, thereby driving the measuring mechanism to rotate circumferentially.

[0012] A second driving mechanism, the output end of the second driving mechanism is connected to the bottom end of the inner shaft. The second driving mechanism is configured to drive the inner shaft to rotate, thereby driving the measuring mechanism to move radially.

[0013] Preferably, it further includes a support disk and a rotating disk. A plurality of balls are arranged at intervals along the circumferential direction on the top surface of the support disk. The support disk and the rotating disk are connected by rolling through the balls. The measuring arm is fixedly installed on the rotating disk, and the outer shaft passes through the support disk and is fixedly connected to the rotating disk.

[0014] Preferably, a graphite sleeve is further sleeved on the top of the outer shaft. The top end of the graphite sleeve is fixedly connected to the support disk. The outer shaft passes through the graphite sleeve and the support disk, and the top end is fixedly connected to the rotating disk.

[0015] Preferably, the measuring arm is a rectangular box-shaped bracket. The box-shaped bracket includes two parallel and spaced longitudinal beams and two cross beams respectively connecting the two ends of the two longitudinal beams. Guide rails are arranged along the length direction on the inner side walls of the two longitudinal beams.

[0016] Preferably, the measuring mechanism includes a probe trolley, a small gear, a rack, a probe bracket, a probe and a slider. The probe trolley is slidably connected to the guide rail of the measuring arm through the slider. The rack is installed on the probe trolley. The rack is arranged parallel to the longitudinal beam of the measuring arm. The top end of the inner shaft is fixedly connected to the small gear. The small gear meshes with the rack. The probe bracket is fixedly installed on the probe trolley. The probe is fixedly installed on the probe bracket.

[0017] Preferably, the measuring mechanism further includes a radial glass grating. The radial glass grating is fixedly installed on one side of the rack for measuring the radial position of the probe.

[0018] Preferably, the first driving mechanism includes a first motor bracket, a connecting flange, a first driving motor, a first coupling, and a first transmission mechanism. The first driving motor is fixedly installed on the first motor bracket, the top end of the first motor bracket is fixedly installed on the bottom surface of the lower yoke of the cyclotron through the connecting flange, and the output end of the first driving motor is in transmission connection with the outer shaft through the first transmission mechanism and the first coupling.

[0019] Preferably, the measuring mechanism further includes an angular encoder, which is fixedly installed on the first motor bracket and used to measure the circumferential position of the measuring arm. The outer shaft passes through the angular encoder and is fixedly connected to the rotating disk at the top end.

[0020] Preferably, the second driving mechanism includes a second motor bracket, a second driving motor, a second coupling, and a second transmission mechanism. The second driving motor is fixedly installed, and the output end of the second driving motor is in transmission connection with the bottom end of the inner shaft through the second transmission mechanism and the second coupling. The inner shaft passes through the outer shaft and is connected to the measuring mechanism at the top end.

[0021] Preferably, the inner shaft is a hollow shaft, and the signal lines of the probe and the radial grating pass through the inner shaft and are connected to a computer.

[0022] Due to the above technical solutions adopted by the present invention, it has the following advantages:

[0023] 1. In the present invention, the angular and radial transmissions adopt a nested shaft transmission, making the measuring device more compact and lighter. The installation accuracy on the cyclotron can be ensured through the accuracy of the measuring device itself, reducing the manual accuracy adjustment during the installation process. <�

[0024] 2. In the present invention, the angular and radial directions adopt a closed-loop operation of a servo motor, a high-precision grating ruler, and an encoder to ensure accurate positioning during the measurement process.

[0025] 3. In the present invention, a high-precision graphite sleeve is installed on the transmission nested shaft to ensure the concentricity of the nested shaft and the magnet and reduce the vibration generated by friction during the transmission process. A structure supported by ceramic balls is used below the measuring arm to reduce the vibration generated by friction during the angular movement of the measuring arm. All materials are non-magnetic materials such as ceramics, graphite, and stainless steel, which can further improve the measurement accuracy;

[0026] The radial movement adopts a rack drive to avoid the phenomenon of synchronous belt slipping; in order to ensure that the Hall probe can be accurately positioned in the mid-plane of the cyclotron, the probe support is designed as a structure that can be adjusted up and down. Description of the Drawings

[0027] Figure 1Usage state diagram of the magnetic field measurement device provided by an embodiment of the present invention;

[0028] Figure 2 Schematic structural diagram of the magnetic field measurement device in an angular direction in this embodiment of the present invention;

[0029] Figure 3 Schematic structural diagram of the magnetic field measurement device in another angular direction in this embodiment of the present invention;

[0030] Figure 4 Schematic structural diagram of the magnetic field measurement device in this embodiment of the present invention after removing the measurement part and the driving part;

[0031] Figure 5 Schematic structural diagram of the measuring arm and the measuring mechanism of the present invention;

[0032] Explanation of reference numerals:

[0033] 1 - Lower yoke, (2) - Lower pole head, (3) - Measuring device, (31) - Outer shaft, (32) - Inner shaft, (33) - Measuring arm, (34) - Measuring mechanism, (35) - First driving mechanism, (36) - Second driving mechanism, (37) - Rotating disk, (38) - Graphite sleeve, (39) - Support disk, (331) - Longitudinal beam, (332) - Cross beam, (333) - Guide rail, (341) - Probe trolley, (342) - Probe support, (343) - Hall probe, (344) - Slide block, (345) - Rack, (346) - Pinion, (347) - Radial grating, (351) - First motor support, (352) - Connecting flange, (353) - First driving motor, (354) - First connecting flange, (355) - First transmission mechanism, (3551) - First driving gear, (3552) - First transmission gear, (361) - Second motor support, (362) - Second driving motor, (3631) - Second driving gear, (3632) - Second transmission gear, (364) - Second coupling. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0035] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the above-mentioned components. Without additional statements, the above terms have no special meanings and should not be construed as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0037] As Figure 1 shown, an embodiment of the present invention provides a magnetic field measurement device for a cyclotron. A beam injection hole is formed along the central axis on the lower yoke 1 of the cyclotron. The magnetic field measurement device 3 passes through the beam injection hole. The measurement part of the measurement device 3 is located in the central plane between the upper pole head (not shown in the figure) and the lower pole head 2 of the cyclotron, and is used to measure the magnetic field strength at various positions within the magnetic field pole surface range. The driving part of the measurement device 3 is located at the bottom of the lower yoke 1 and is used to drive the measurement part to move along the angular and radial directions.

[0038] Combined with Figure 2 、 Figure 3 and Figure 4As shown in the figure, the magnetic field measuring device 3 includes: an outer shaft 31, an inner shaft 32 sleeved inside the outer shaft 31, a measuring arm 33, a measuring mechanism 34 mounted on the measuring arm 33, a first driving mechanism 35, and a second driving mechanism 36. The top end of the outer shaft 31 is connected to the measuring arm 33. The inner shaft 32 is sleeved inside the outer shaft 31, and both ends of the inner shaft 32 extend out of the outer shaft 31. The top end of the inner shaft 32 is connected to the measuring mechanism 33 on the measuring arm 33. The output end of the first driving mechanism 35 is connected to the bottom end of the outer shaft 31 and is used to drive the outer shaft 31 to rotate. The rotation of the outer shaft 31 drives the measuring arm 33 and the measuring mechanism 34 mounted on the measuring arm 33 to rotate circumferentially. The output end of the second driving mechanism 36 is connected to the bottom end of the inner shaft 32 and is used to drive the inner shaft 32 to rotate. The rotation of the inner shaft 32 drives the measuring mechanism 34 to move radially. The measuring mechanism 34 is used to measure the magnetic field strength.

[0039] In the present invention, the measuring arm 33 and the measuring mechanism 34 mounted on the measuring arm 33 are located in the central plane of the gap between the upper pole head and the lower pole head 2. The measuring mechanism 34 is used to measure the magnetic field strength between the upper pole head and the lower pole head 2. A beam injection hole is provided on the lower yoke 1 along the central axis. The outer shaft 31 and the inner shaft 32 pass through the beam injection hole and are then connected to the measuring arm 33. The first driving mechanism 35 and the second driving mechanism 36 are mounted at the bottom of the lower yoke 1 and are used to drive the outer shaft 31 and the inner shaft 32 to rotate respectively. The rotation of the outer shaft 31 directly drives the measuring arm 33 and the measuring mechanism 34 mounted on the measuring arm 33 to rotate circumferentially. The rotation of the inner shaft 32 drives the measuring mechanism 33 to move along the advancing direction of the measuring arm 33, so that the measuring mechanism 34 can detect along the circumferential direction and the radial direction in the central plane of the magnetic field, and thus realize omnidirectional magnetic field detection.

[0040] The magnetic field measuring device provided by the present invention adopts the method of mutually sleeving the inner shaft 32 and the outer shaft 31 to form a sleeve shaft for angular and radial transmission, and the sleeve shaft passes through the beam injection hole. Compared with the prior art in which the angular and radial transmission shafts pass through the beam injection hole and the reserved hole of the high-frequency cavity respectively, the measuring platform can be made more compact and lighter. The installation accuracy on the cyclotron is ensured by the accuracy of the measuring platform itself, and the accuracy adjustment during the installation process is reduced.

[0041] As Figure 5As shown, preferably, the measuring arm 33 is a rectangular box-shaped bracket. The box-shaped bracket includes two parallel and spaced longitudinal beams 331 and two cross beams 332 respectively connecting the two ends of the longitudinal beams 331. Guide rails 333 are provided along the length direction on the inner side walls of the two longitudinal beams 331. The measuring mechanism 34 is installed on the measuring arm 33 and slides along the guide rails 333 on the measuring arm 33, so as to realize the movement in the radial direction. The measuring arm 33 is located in the central plane between the upper pole tip and the lower pole tip 2. In order to further improve the connection strength between the two opposite longitudinal beams 331, several cross beams 332 for connection and reinforcement are also provided between the cross beams 332 at both ends.

[0042] It can be understood that the measuring arm 33 is not limited to being set as a box shape. The measuring arm 33 can also be set to include only one longitudinal beam 331. The longitudinal beam 331 is installed on the rotating disk 37. Guide rails 333 are provided along the length direction on the longitudinal beam 331. The measuring mechanism 34 moves along the length direction of the guide rails 333 under the driving action of the second driving mechanism 36 and the inner shaft 32. Or, the measuring arm 33 can also be set to include two parallel longitudinal beams 331 spaced at a certain distance and at least one cross beam 332 connecting the two longitudinal beams 331. A slider 334 that slides along the guide rails 333 is installed on the longitudinal beam 331. The above methods and any method that can realize the horizontal sliding of the measuring mechanism 34 along the guide rails 333 should be within the protection scope of the present invention.

[0043] For the convenience of installation, the measuring device further includes a rotating disk 37. The measuring arm 33 is fixedly installed on the rotating disk 37. The top of the outer shaft 31 is fixedly connected to the rotating disk 37 for driving the rotating disk 37 and the measuring arm 33 to rotate.

[0044] In order to ensure the parallelism between the measuring arm 33 and the accelerator pole tip surface and reduce the vibration caused by friction during the angular movement of the measuring arm, thereby further improving the measurement accuracy, the measuring device 3 further includes a support disk 39. The support disk 39 contacts the cyclotron pole surface. The outer shaft 31 passes through the beam injection hole and is fixedly connected to the bottom of the rotating disk 37. And a plurality of balls 391 are provided at intervals along the axial direction on the top surface of the support disk 39. The support disk 39 is in rolling connection with the rotating disk 37 through the balls 391. Preferably, the balls 391 are made of ceramic materials.

[0045] In order to further improve the concentricity between the outer shaft 31 and the inner shaft 32 and the rotary accelerator 1 during rotation, and at the same time reduce the vibration caused by friction during the angular movement of the sleeve shaft, so as to further improve the measurement accuracy, a graphite sleeve 38 with high machining accuracy is also sleeved on the contact part between the outer shaft 31 and the beam injection hole of the accelerator. The top end of the graphite sleeve 38 is fixedly connected to the support disk 39, so that it can be avoided that the sleeve shaft directly contacts the beam injection hole during rotation, and thus the friction and vibration generated during rotation can be further reduced. The graphite sleeve 38 can play a lubricating role, so that the measurement accuracy can be further improved.

[0046] The measuring mechanism 34 includes a probe trolley 341, a pinion 346, a rack 345, a probe support 342, a probe 343 and a slider 344. The slider 344 is installed on one side of the probe trolley 341. The probe trolley 341 is slidably connected to the guide rail 333 of the measuring arm 33 through the slider 344. The rack 345 is installed on the probe trolley 341. The rack 345 is arranged parallel to the longitudinal beam of the measuring arm 33. The top end of the inner shaft 32 is fixedly connected to the pinion 346. The pinion 346 meshes with the rack 345. The probe support 342 is fixedly installed on the probe trolley 341, preferably installed at one end of the probe trolley 341. The probe 343 is fixedly installed on the probe support 342. The second driving mechanism 36 drives the inner shaft to rotate. The rotation of the inner shaft 32 drives the pinion 346 to rotate. The pinion 346 meshes with the rack 345. The rack 345 moves along the horizontal direction, thereby driving the probe trolley 341 to slide along the guide rail 333. The sliding of the probe trolley 341 drives the probe 343 installed on the probe trolley 341 to move along the radial direction.

[0047] The probe 343 is preferably a Hall probe. The probe support 342 is fixedly installed at one end of the probe trolley 341. Therefore, when the probe trolley 341 moves along the guide rail 333, it can drive the probe 343 to move along the radial direction. Among them, preferably, when the probe trolley 341 moves radially, the probe support 342 can move within the range of -20 mm to +820 mm.

[0048] The probe carriage 341 is located within the measured arm. The probe carriage 341 includes two longitudinal rods that are parallel to each other and spaced apart, and two cross rods connecting the two ends of the two longitudinal rods. The two longitudinal rods are parallel to the two longitudinal beams, and the two cross rods are parallel to the two cross beams. At least one slider 344 is provided on the outer sides of the two longitudinal rods. The slider 344 cooperates with the guide rail 333 and slides along the guide rail 333. The probe support 341 is fixedly installed on the cross rod at one end thereof, and the probe 343 is fixedly installed on the probe support 342. The rack 345 is fixedly installed on the probe carriage 341, and the rack 345 is parallel to the two longitudinal rods. When the pinion 346 rotates, it drives the rack 345 to move, and the movement of the rack 345 drives the probe carriage 342 and the probe 343 to move along the radial direction.

[0049] It can be understood that the probe carriage 341 is not limited to the above box-shaped structure design. The probe carriage 34 can also be provided with only one longitudinal rod. The rack is fixedly installed on the longitudinal rod and is parallel to the longitudinal rod. One side of the longitudinal rod is slidably connected to the guide rail 333 through the slider 344. When the rack 345 slides along the radial direction, it drives the probe support 342 and the probe 343 to move. The present invention regarding the probe carriage 341 is not limited to the above manner. As long as it can follow the rack 345 to slide along the radial direction and at the same time drive the probe support 342 and the probe 343 mounted thereon to move along the radial direction, it is within the protection scope of the present invention.

[0050] In order to adjust the position of the probe 343 in the direction perpendicular to the middle plane, the probe support 342 is fixedly installed at the end of the probe carriage 341, and the probe support 341 can also be adjusted up and down. The method of adjusting the height of the probe support 342 can be, for example, fixedly installed on the probe carriage 341 by screws. By screwing the screws, the height of the probe can be adjusted, thereby further improving the accuracy of magnetic field measurement. Or the probe support 342 can be provided in a telescopic manner, such as a telescopic rod, and the probe 343 is fixedly installed on the telescopic rod, so as to realize the adjustment of the height of the probe.

[0051] Furthermore, in order to accurately locate the radial position of the probe 343 and more accurately move the probe 343 to the required radial position, the measuring mechanism 34 also includes a radial glass grating 347, which is fixedly mounted on one side of the rack 345. The radial glass grating 347 accurately locates the radial position of the probe 343 and transmits the positioning signal to a computer or controller. The controller compares the actual positioning signal of the probe 343 with the target positioning, thereby controlling the second driving mechanism 36 to form a closed-loop control.

[0052] In order to facilitate signal transmission and installation and make the structure of the measuring device 3 more compact, the inner shaft is a hollow shaft, and the signal line of the Hall probe 343 and the radial glass grating 347 installed on the Hall probe bracket 342 are led out from the inner shaft to the computer. When the measuring arm 33 moves angularly and radially, the Hall probe 343 signal and the radial and angular positions are accurately collected to obtain accurate magnetic field distribution data.

[0053] Combine Figure 2 and Figure 3 As shown, as a preferred embodiment of the present invention, the first drive mechanism 35 includes: a first motor bracket 351, a connecting flange 352, a first drive motor 353, a first coupling 354, and a first transmission mechanism 355. The first drive motor 353 is fixedly mounted on the first motor bracket 351. The top end of the first motor bracket 351 is fixedly mounted to the bottom surface of the lower iron yoke 1 of the cyclotron via the connecting flange 352. The output end of the first drive motor 353 is connected to the outer shaft 31 via the first transmission mechanism 355 and the first coupling 354. The first drive motor 353 can drive the outer shaft 31 to rotate, thereby driving the measuring arm 33 to rotate, thereby adjusting the angular position of the probe 343.

[0054] It is understandable that the first driving mechanism 35 can also be replaced by a driving mechanism such as a rotary cylinder or a rotary oil cylinder, as long as it can drive the outer shaft 31 to rotate.

[0055] As a preferred way among them, the first transmission mechanism 355 includes a first driving gear 3551, a first driven gear 3552 and a synchronous belt connecting the first driving gear 3551 and the first driven gear 3552. The output end of the first driving motor 353 is fixedly connected to the first driving gear 3551. The first driving gear 3551 and the first driven gear 3552 are drivingly connected through the first synchronous belt. The gear shaft of the first driven gear 3552 is connected to the outer shaft 31 through a first coupling 351. The gear shaft of the first driven gear 3552 is hollow like the outer shaft 31. The inner shaft 32 passes through the gear shaft of the first driven gear 3552, the first coupling 354 and the outer shaft 311, and the top extends out from the top end of the outer shaft 31.

[0056] It can be understood that the first transmission mechanism 355 can also be arranged such that the first driving gear 3551 and the first driven gear 3552 are directly drivingly connected through the meshing of teeth, or the first driving gear 3551 and the first driven gear 3552 are drivingly connected through a chain drive. However, in order to ensure the measurement accuracy, it is preferably to adopt the synchronous belt drive or the way of tooth meshing drive.

[0057] In order to accurately position the angular position of the probe, the measuring device provided by the present invention further includes an angular encoder 357. The angular encoder 357 is fixed on the first motor bracket 351. The gear shaft of the first driven gear 3552 passes through the angular encoder 357. When the first driving motor 353 drives the outer shaft 31 to rotate, it can form a closed-loop operation with the first driving motor 353 to accurately position the angular position of the measuring arm. The angular encoder 357 measures the number of rotation turns of the outer shaft 31 to obtain the angular velocity of the rotation of the outer shaft 31, and sends the detected signal to the computer. The computer obtains the actual circumferential position of the probe according to the detected signal and controls the first driving motor 353, so as to finally obtain the accurate circumferential position.

[0058] The second driving mechanism 36 includes a second motor bracket 361, a second driving motor 362, a second coupling 364 and a second transmission mechanism 363. The second driving motor 362 is fixedly installed on the second motor bracket 361. The output end of the second driving motor 362 is drivingly connected to the inner shaft 32 through the second transmission mechanism 363 and the second coupling 364.

[0059] The top of the second motor bracket 361 is fixedly connected to the bottom of the first motor bracket 351 or the bottom of the lower yoke 1. The gear shaft of the first driven gear 3552 passes through the angular encoder 357 and is connected to the outer shaft 31 through the first coupling 354. The second driving motor 353 is fixedly installed on the second motor bracket 361. The second transmission mechanism 363 includes a second driving gear 3631, a second driven gear 3632, and a second synchronous belt connecting the second driving gear 3631 and the second driven gear 3632. The output end of the second driving motor 362 is fixedly connected to the second driving gear 3631. The bottom of the inner shaft 32 passes through the bottom of the outer shaft 31 and is drivingly connected to the gear shaft of the second driven gear 3632 through the second coupling 364. The second driving motor 363 drives the inner shaft 32 to rotate, and the rotation of the inner shaft 32 drives the probe bracket 342 and the probe 343 to move along the radial direction of the measuring force arm.

[0060] The working principle of the above magnetic field measuring device is as follows:

[0061] The first driving mechanism 35 drives the outer shaft 32 to rotate. The rotation of the outer shaft 32 drives the measuring arm 33 to rotate. The rotation of the measuring arm 33 drives the probe bracket 342 and the probe 343 installed on the probe bracket 342 to rotate, so as to adjust the angular position of the probe 343 within the pole face range. When the probe 343 moves to the required angular position, the second driving mechanism 36 drives the inner shaft 32 to rotate. The rotation of the inner shaft 32 drives the small gear 346 to rotate. The rotation of the small gear 346 drives the rack 345 and the probe carriage 341 to slide along the guide rail 33. The sliding of the probe carriage 341 drives the probe bracket 342 and the probe 343 installed on the probe bracket 342 to move along the forward direction, so as to realize the adjustment of the angular and radial positions of the probe 343 within the pole face azimuth. At the same time, in order to more accurately position the radial and angular positions of the probe 343, a closed-loop control is formed to further improve the positioning accuracy. The radial grating 347 accurately detects the radial position of the probe 343 and transmits the positioning signal to a computer or a controller. The controller compares the actual positioning signal of the probe with the target positioning, so as to control the second driving mechanism 36 and form a closed-loop control. Similarly, the angular encoder 357 detects the angular position of the probe and sends the detection signal to the computer. The computer compares the detected actual angular position with the target angular position, so as to control the first driving mechanism 35 and form a closed-loop control.

[0062] In the present invention, angular and radial transmissions adopt a sleeve shaft transmission. All materials are non-magnetic materials such as ceramics, graphite, and stainless steel, making the measuring device 3 more compact and lighter. The installation accuracy on the cyclotron 1 can be ensured through the accuracy of the measuring device 3 itself, reducing the manual accuracy adjustment during the installation process.

[0063] In the present invention, angular and radial directions adopt a closed-loop operation of a servo motor, a high-precision grating scale 347, and an encoder 357 to ensure precise positioning during the measurement process.

[0064] In the transmission sleeve shaft of the present invention, a high-precision graphite sleeve 38 is installed to ensure the concentricity of the sleeve shaft and the magnet and reduce the vibration generated by friction during the transmission process. A structure supported by ceramic balls 391 is used below the measuring arm to reduce the vibration generated by friction during the angular movement of the measuring arm. Rack transmission is adopted for radial movement to avoid the phenomenon of synchronous belt slipping. To ensure that the Hall probe can be accurately positioned in the mid-plane of the cyclotron, the probe support is designed as a structure that can be adjusted up and down.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A magnetic field measurement device for a cyclotron, characterized in that, include: The outer shaft and the inner shaft are coaxially sleeved, and both ends of the inner shaft extend from the outer shaft; a measuring arm connected to a top end of the outer shaft; a measuring mechanism mounted on the measuring arm and connected to the top end of the inner shaft, the measuring mechanism being configured to measure the magnetic field strength at various positions within the magnetic field polar plane of the cyclotron; a first drive mechanism, wherein the output end of the first drive mechanism is connected to the bottom end of the outer shaft, the first drive mechanism is configured to drive the outer shaft to rotate, thereby driving the measuring mechanism to rotate circumferentially, the first drive mechanism comprising a first motor bracket, a connecting flange, a first drive motor, a first coupling, and a first transmission mechanism, the first drive motor being fixedly mounted on the first motor bracket, the top end of the first motor bracket being fixedly mounted to the bottom surface of the lower iron yoke of the cyclotron via the connecting flange, and the output end of the first drive motor being in transmission connection with the outer shaft via the first transmission mechanism and the first coupling; a second drive mechanism, wherein the output end of the second drive mechanism is connected to the bottom end of the inner shaft, and the second drive mechanism is configured to drive the inner shaft to rotate, thereby driving the measuring mechanism to move radially, the second drive mechanism comprising a second motor bracket, a second drive motor, a second coupling, and a second transmission mechanism, the second drive motor is fixedly installed, and the output end of the second drive motor is connected to the bottom end of the inner shaft via the second transmission mechanism and the second coupling, the inner shaft passes through the outer shaft, and the top end is connected to the measuring mechanism; The measuring mechanism includes a probe trolley, a gear, a rack, a probe holder, a probe and a slider. The probe trolley is slidably connected to the guide rail of the measuring arm via the slider. The rack is mounted on the probe trolley and is arranged parallel to the longitudinal beam of the measuring arm. The top end of the inner shaft is fixedly connected to the gear, and the gear is meshed with the rack. The probe holder is fixedly mounted on the probe trolley, and the probe is fixedly mounted on the probe holder. The measuring mechanism further includes a radial glass grating fixedly mounted on one side of the rack and configured to measure the radial position of the probe and transmit a positioning signal to a computer or controller. The controller compares the actual positioning signal of the probe with the target positioning, thereby controlling the second driving mechanism to form a closed-loop control. The inner shaft is a hollow shaft. The signal lines of the probe and the radial glass grating pass through the inner shaft and are connected to a computer. The Hall probe signal line and the radial glass grating signal line installed on the Hall probe bracket are led out from the inner shaft to the computer. When the angular and radial movements of the measuring arm are made, the Hall probe signal and the radial and angular positions are accurately collected to obtain accurate magnetic field distribution data.

2. The magnetic field measuring device according to claim 1, characterized in that It further includes a support disk and a rotating disk. A plurality of rolling balls are arranged at intervals along the circumferential direction on the top surface of the support disk. The support disk and the rotating disk are in rolling connection through the rolling balls. The measuring arm is fixedly installed on the rotating disk, and the outer shaft passes through the support disk and is fixedly connected to the rotating disk.

3. The magnetic field measuring device according to claim 2, wherein A graphite sleeve is further sleeved on the top of the outer shaft. The top end of the graphite sleeve is fixedly connected to the support disk. The outer shaft passes through the graphite sleeve and the support disk, and the top end is fixedly connected to the rotating disk.

4. The magnetic field measuring device according to claim 1, characterized in that The measuring arm is a rectangular box-shaped bracket. The box-shaped bracket includes two parallel and spaced longitudinal beams and two cross beams respectively connecting the two ends of the two longitudinal beams. Guide rails are arranged along the length direction on the inner side walls of the two longitudinal beams.

5. The magnetic field measuring device according to claim 1, characterized in that The measuring mechanism further includes an angular encoder. The angular encoder is fixedly installed on the first motor bracket and is used to measure the circumferential position of the measuring arm. The outer shaft passes through the angular encoder, and the top end is fixedly connected to the rotating disk.

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