CN201322791Y - Device for measuring magnetic field distribution of superconducting magnet - Google Patents

Abstract

A device for measuring the magnetic field distribution of a superconducting magnet, comprising a measuring rod (1), a locking fixture (2), a guide sleeve (3), a mounting plate (4), an XY translation stage (5), and a rotation stage (6) , conversion plate (7) and probe fixture (8). The rotary table (6) is installed on the conversion plate (7), the XY translation table (5) is installed on the rotary table (6), the mounting plate (4) is fixed on the XY translation table (5), and the guide sleeve (3) is fixed On the mounting plate (4), the locking jig (2) is installed on the end face of the guide sleeve (3), and the measuring rod (1) is inserted into the inner hole of the guide sleeve (3) through the hole of the locking jig (2), and passed through XY translation stage (5), rotation stage (6) and conversion plate (7). The probe fixture (8) is installed on the lower end of the measuring rod (1). By adjusting the knob of the mechanism, the measuring probe can be translated in the three directions of XYZ and rotated 360° around the Z axis to realize the measurement of the magnetic field at any point in the room temperature hole of the superconducting magnet.

Description

A device for measuring the magnetic field distribution of a superconducting magnet

technical field

The utility model relates to a device for measuring the magnetic field distribution of a superconducting magnet, in particular to a device for measuring the magnetic field distribution in a hole of a superconducting magnet at room temperature.

Background technique

An important problem in the magnetic field measurement of superconducting magnets is that the Gauss meter probe is difficult to locate, and it is impossible to correspond the magnetic field measurement value with the precise spatial coordinates. In some magnetic field measurements, the precise positioning of spatial coordinate points is crucial to the measurement results. Such as a gyrotron microwave magnet, the required positioning accuracy of the magnetic axis is less than 0.2mm. If the magnetic axis deviation is too large, it will cause the deviation of the microwave beam or even burn the microwave tube. Therefore, an accurate measuring and positioning device is needed to measure the magnetic field distribution of the superconducting magnet.

In 1986, Harbin Electric Instrument Institute Teng Ruilin and others developed a CG6 NMR calibration device. Microcomputer control, three-dimensional measurement of the magnetic field distribution in the superconducting strong magnet, using a micro-stepping motor, 60,000 steps/360 degrees. However, the micro-stepping motor is a ferromagnetic component, which will change the magnetic field pattern of the measured area and affect the measurement accuracy. However, superconducting magnets are all produced in one piece, and the Dewars have different shapes, so this instrument cannot meet the requirements of measurement versatility. In 2003, Chen Xianfeng, School of Automation, Nanjing University of Technology, etc. proposed a three-dimensional space magnetic field and magnetic force test system using AC servo control. The system uses an AC servo motor to drive a ball screw to achieve automatic measurement. Obviously, AC servo motors and ball screws are themselves ferromagnetic components, which introduce errors in the magnetic field. The implementation and operation of the system are complicated, which is not conducive to the use in superconducting magnet debugging field. The three-dimensional magnetic field distribution automatic measurement equipment of Yipin Magnetic Industry Co., Ltd. focuses on the improvement of the measurement accuracy of the magnetic field value and the adoption of automatic measurement methods. The magnetic field step-by-step measuring instrument of Harbin Xianda Electronics Co., Ltd. is mainly used to measure the surface magnetic field of permanent magnets. None of these magnetic field measurement products involves accurate measurement of the magnetic field of superconducting magnets.

Similar foreign measuring devices are mainly magnetic field measuring equipment for MRI, which are used to measure uniformity and gradient. US2004254449 (A1) "System for concurrent MRIimaging and magnetic field homogeneity measurement", mainly used to measure the homogeneity of MRI magnetic field. JP4276236 (A) "TIME CHANGE MEASUREMENT METHOD FOR GRADIENT MAGNETIC FIELD OF MRIDEVICE" measures the magnetic field change and gradient of the MRI device.

Positioning devices for measurement, such as sample stages and workpiece stages commonly used in scientific instruments, electron microscopes, electron probes, etc., often use translation devices and rotary stages in X and Y directions. However, there is no long measuring rod in the z direction on these flat or mobile platforms. The main reason is that the far end of the long measuring rod cannot guarantee the verticality with the table surface, and the verticality is very important in the magnetic field measurement, because the magnetic field measurement needs to measure the diameter separately. To ensure the verticality of the magnetic field and the axial magnetic field, the accuracy of each measurement component can be guaranteed. In addition, steel rails and turntables cannot be used for magnetic field measurements.

Based on the above, there is no measurement and positioning device for superconducting magnets in domestic and foreign products, patents and documents. The methods currently used by superconducting magnet development units are to use specially designed installation and positioning measurement fixtures for specific magnets. Therefore, In the commissioning and installation of superconducting magnets, a professional, general-purpose, and high-precision magnetic field measurement and positioning device is required.

Utility model content

The purpose of the utility model is to overcome the disadvantages that the existing measuring device cannot accurately locate, especially the perpendicularity of the magnetic field measurement, and propose a device for measuring the magnetic field distribution of a superconducting magnet. The utility model can precisely position the measuring probe of the gauss meter, automatically center the axis of the probe and the axis of the measuring rod, and make the measuring rod coaxial with the inner hole of the magnet through the guide sleeve structure and the auxiliary bracket. The utility model makes the measuring probe translate in XYZ three directions and rotate 360° around the Z axis by adjusting the mechanism knob to measure the magnetic field at any point in the room temperature hole of the superconducting magnet.

The utility model comprises a measuring rod, a locking fixture, a guide sleeve, a mounting plate, an XY translation stage, a rotary stage, a conversion plate, and a probe fixture. The rotary table is installed on the conversion plate; the XY translation table is installed on the rotary table; the mounting plate is fixed on the XY translation table; the guide sleeve passes through the center hole of the mounting plate and is fixed on the mounting plate; the locking fixture is installed on the end surface of the guide sleeve ; The probe fixture is installed at the lower end of the measuring rod.

The measuring rod is inserted into the inner hole of the guide sleeve, and the guide sleeve is installed on the XY translation table through the mounting plate. The XY translation table is a square hollow structure, and the rotation table and the conversion plate are both hollow structures. The measuring rod moves up and down in the Z direction along the inner hole of the guide sleeve. Free movement, the XY translation stage moves the measuring rod along the XY direction, thus realizing the translation of the three degrees of freedom of XYZ. The rotary table can rotate the measuring rod 360 degrees around the Z axis.

The measuring rod is made of aluminum alloy, and the straightness is 0.01% calibrated before processing. There is a scale on the measuring rod.

There are three fine-tuning screws on the guide sleeve, which are used to adjust the verticality of the axis of the inner hole of the guide sleeve and the table top. When the measuring rod is inserted into the inner hole of the guide sleeve, the verticality of the measuring rod can meet the requirements through the fine-tuning screws.

The utility model includes an accessory of an auxiliary positioning bracket. The auxiliary positioning bracket is installed in the inner hole of the magnet to be measured.

The guide sleeve, mounting plate, XY translation stage and rotary table body of the utility model superconducting magnet magnetic field distribution measurement device use hard aluminum alloy base material; the guide rail slider of the X direction and Y direction guide rail adopts anti-friction copper alloy; the rotary table bearing, Screws, nuts and other connecting parts are made of non-magnetic stainless steel, and the whole device has no ferromagnetic parts, so as to avoid interference with magnetic field detection.

The measuring rod of the superconducting magnet magnetic field distribution measuring device can move up and down to provide millimeter-level Z-axis positioning accuracy, and the translation accuracy in the horizontal plane can reach 0.05 mm, which meets the requirements of high-precision positioning. The rotation accuracy around the Z-axis can reach 0.5 degrees, and the above accuracy It can be improved as needed.

With the utility model, the following measurements can be realized: the distribution of the magnetic field along the axis, the distribution of the magnetic field in the Z0 plane at a certain axial position, the distribution of the magnetic field along the radius R0 in the Z0 plane, and other measurements suitable for the utility model.

The device of the utility model can be used in cooperation with the common gauss meter currently on the market, has simple operation, accurate positioning and strong versatility, and can meet the measurement of the magnetic fields of most superconducting magnets at present.

Description of drawings

Fig. 1a is a structural diagram of a superconducting magnet magnetic field distribution measuring device, and Fig. 1b is a cross-sectional view. In the figure: 1 measuring rod, 2 locking fixture, 3 guide sleeve, 4 mounting plate, 5XY translation stage, 6 rotating stage, 7 conversion plate, 8 detector fixture;

Figure 2a is a structural diagram of the XY translation stage 5, in which: 9X translation stage, 10Y translation stage, 11Y scale scale, 12X scale scale, 13Y displacement knob, 14X displacement knob; Figure 2b is a partial view of the guide rail, 15 guide rail sliders, 16X direction guide rail, 17 guide rail substrate, 18Y direction guide rail;

Fig. 3 is a structural diagram of the turntable 6, in which: 19 locking knob, 20 turntable handle, 21 sliding bearing, 22 upper table top and 23 lower table top;

Fig. 4 is a structural diagram of guide sleeve 3 and mounting plate, in the figure: 24 horizontal fine-tuning screws; 25 mounting screws;

Fig. 5a is a structural diagram of the probe fixture 8, and Fig. 5b is a sectional view of the probe fixture 8A-A, in which: 26 locking nuts, 27 probe chucks;

Fig. 6 is a structural diagram of the locking fixture 2, in the figure: 28 locking screws;

Fig. 7 is the structural diagram of conversion board;

Fig. 8 is a schematic diagram of the auxiliary positioning bracket in the magnet inner hole, in the figure: 29 auxiliary positioning bracket, 30 magnet inner hole, 31 upper disc, 32 lower disc;

Fig. 9 is a specific implementation diagram of measuring the magnetic field distribution of a superconducting magnet using the device of the present invention, in the figure: 33 gauss meters, 34 probe connecting cables, 35 superconducting magnets;

Fig. 10 is a diagram of the axial magnetic field distribution of a superconducting magnet measured by the device of the utility model;

Fig. 11 is a diagram of the circumferential magnetic field distribution of a superconducting magnet with an axial position of 350mm and a radius of 20mm measured by the device of the utility model.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the utility model is further described.

As shown in Figures 1a and b, the utility model includes a measuring rod 1, a locking fixture 2, a guide sleeve 3, a mounting plate 4, an XY translation stage 5, a rotating stage 6, a conversion plate 7, and a probe fixture 8. The rotary table 6 is installed on the conversion plate 7; the XY translation table 5 is installed on the rotary table 6; the mounting plate 4 is fixed on the XY translation table 5; the guide sleeve 3 passes through the center hole of the mounting plate 4 and is fixed on the mounting plate 4; The locking fixture 2 is installed on the end surface of the guide sleeve 3; the probe fixture 8 is installed on the lower end of the measuring rod 1.

As shown in FIG. 1 b , the measuring rod 1 passes through the center hole of the locking fixture 2 and is inserted into the inner hole of the guide sleeve 3 , and the guide sleeve 3 passes through the center hole of the mounting plate 4 and is fixed on the mounting plate 4 . As shown in Fig. 2a, the XY translation stage 5 is a square hollow structure. As shown in FIG. 3 , the turntable 6 is a circular hollow structure. As shown in Fig. 1b, the conversion plate 7 is an annular plate with a through hole inside. The measuring rod 1 can move up and down in the Z direction along the inner hole of the guide sleeve 3, and the measuring rod 1 can also be locked by the locking fixture 2 to fix it. There is a scale indication on the measuring rod 1, which can read the Z-axis distance.

As shown in FIG. 2 a , the XY translation stage 5 includes an X translation stage 9 and a Y translation stage 10 , and the X translation stage 9 is located on the Y translation stage 10 . There is a Y scale scale 11 on the side of the Y translation stage 10, and an X scale scale 12 on the side of the X translation stage 9, which are used to indicate the displacement of the guide rail and meet the adjustment accuracy requirement of 0.05 mm. The X direction guide rail 16 is on the top, the Y direction guide rail 18 is on the bottom, and the common guide rail base 17 is in the middle. As shown in Figure 2b, the X-direction guide rail 16 and the Y-direction guide rail 18 adopt the same structure, and there are dovetail grooves on the X-direction guide rail 16 and the Y-direction guide rail 18, and one end of the dovetail groove is matched with the dovetail groove on the guide rail base 17, and the dovetail groove The guide rail slider 15 is embedded in the other end of the groove. The guide rail slider 15 is made of anti-friction copper alloy, and the bodies of the X translation stage 10 and the Y translation stage 9 are made of hard aluminum alloy. By rotating the Y displacement knob 13 and the X displacement knob 14, the displacement can be adjusted within the range of 100×100 mm in the XY direction.

As shown in FIG. 3 , the turntable 6 can rotate 360° around the central axis of the turntable. The rotary table 6 is an upper and lower split structure, the upper table 22 is pressed on the lower table 23, and the upper table 22 and the lower table 23 are supported by a sliding bearing 21. Both the upper table 22 and the lower table 23 are made of aluminum alloy. There is an angle scale scale on the outside of the upper table top 22. The turntable handle 20 can be turned to any angular position by manual rotation. When the locking knob 19 was locked, the turntable could not rotate.

When measuring the magnetic field, the direction parallel to the axis of the room temperature hole of the magnet is the axial magnetic field, that is, the direction of the probe rod axis, and the direction perpendicular to the axis of the magnet room temperature hole is the radial magnetic field, that is, the direction of the measuring device table. The axis of the probe rod and the measuring device table must ensure vertical. But when the detection rod 1 length exceeds 1000mm, its end and the device table are difficult to guarantee verticality, for this reason the utility model has designed the guide sleeve 3 that has fine-tuning screw. As shown in Fig. 4, the guide sleeve 3 has three fine adjustment screws 24 on the horizontal plane. By adjusting the height of the screws, the verticality of the detection rod 1 can be slightly adjusted so that the verticality of the measuring rod meets the measurement requirements. The guide sleeve 3 is fixed on the mounting plate 4 by three mounting screws 25 .

As shown in Fig. 5a and Fig. 5b, the probe clamp 8 is used to fix the Gauss meter probe. The probe fixture 8 includes a lock nut 27 and a probe clamp 26 . Both the upper and lower parts of the probe chuck 26 have threads, and the upper thread cooperates with the inner hole thread of the lower end of the measuring rod 1 to fix the probe fixture 8 on the lower end of the measuring rod 1; the lower part of the thread cooperates with the lock nut 27 for Secure the gaussmeter probe. The probe chuck 26 has a cross groove. During the locking process of the lock nut 27, the cross groove of the probe chuck 26 is forced to close from the surrounding to the inside to realize automatic centering, so that the axis of the probe coincides with the axis of the measuring rod 1. .

As shown in FIG. 6 , there is an opening at one end of the locking fixture 2 , and the measuring rod 1 can be locked by the locking screw 28 , so that the Z coordinate is fixed at a certain position during measurement.

As shown in Figure 7, the conversion plate 7 is a disc with a circular hole in it, and the conversion plate 7 is used to install the turntable 6. On the conversion plate 7, holes can be punched according to the room temperature hole of the magnet to be measured, so that the whole measuring mechanism can be fixed on the on the magnet.

As shown in FIG. 8 , the auxiliary positioning bracket 25 is formed by connecting an upper disk 31 and a lower disk 32 with a hollow rod in the middle. Upper disk 31, perforate in the middle of lower disk 32, the size of hole guarantees to fit tightly with measuring rod 1. The end faces of the upper disc 31 and the lower disc 32 are parallel, and the end faces of the upper and lower discs are perpendicular to the axis of the inner hole. Auxiliary positioning bracket 25 materials select organic glass, aluminum and other non-magnetic materials. Auxiliary positioning support 29 is installed in magnet inner hole 30, and main function is when measuring rod 1 penetrates too long in the magnet room temperature hole, guarantees that measuring rod and magnet inner hole are coaxial. The auxiliary positioning bracket 29 is inserted into the inner hole 30 of the magnet; the measuring rod 1 is inserted into the center hole of the auxiliary positioning bracket 29; the auxiliary positioning bracket 29 is closely matched with the inner hole 30 of the magnet, and the measuring rod 1 is closely matched with the inner hole of the auxiliary positioning bracket 29 to ensure measurement The rod 1 is coaxial with the inner hole 30 of the magnet. The upper disc 31 and the lower disc 32 of the auxiliary positioning support 29 can be loaded with elastic rubber rings so as to closely cooperate with the inner hole.

Fig. 9 is a specific implementation case of applying the utility model to measure the magnetic field. The device of the utility model is installed on the upper cover of the superconducting magnet 35. When installing, it is ensured that the table surface of the device is parallel to the upper surface of the magnet. 35 inner hole axes coincide. Install the gauss meter probe on the probe fixture 8, the probe connection cable 34 is led out from the inner hole of the measuring rod 1, and connected to the gauss meter 33, the probe connection cable 34 should be long enough to keep the gauss meter 33 away from the environment of strong magnetic field Work to avoid measurement deviation due to strong magnetic field. When the measuring rod 1 goes deep into the room temperature hole of the superconducting magnet 35 for too long. The precise positioning of the distal measurement axis can be ensured by means of the auxiliary positioning bracket 29 .

Applying the utility model, the superconducting magnet magnetic field distribution measurement method and steps are as follows:

(1) Install the measuring device on the upper cover of the superconducting magnet 35, and ensure that the central axis of the measuring device coincides with the central axis of the room temperature hole of the superconducting magnet during installation. Make sure that the measuring device table is parallel to the end face of the magnet.

(2) Install the gauss meter probe on the probe fixture 8, move the measuring rod 1 up and down, record the axial scale and the corresponding magnetic field value, and the data of the magnetic field distribution along the axis can be measured, as shown in Figure 10;

(3) The measuring rod 1 is adjusted to a certain axial distance Z0, and the knobs of the XY translation stage 5 are manipulated to translate along the XY direction, and the XY scale and the corresponding magnetic field value are recorded, so that the data of the distribution of the magnetic field in the Z0 plane can be obtained;

(4) Adjust the measuring rod 1 of the measuring device to a certain axial distance Z0, manipulate the knobs of the XY translation table 5 to make X or Y deviate from the axis by a certain distance R0, and turn the rotary table 6 to obtain the distribution of the magnetic field along the radius R0 in the Z0 plane The data. Figure 11 shows the magnetic field distribution diagram of a superconducting magnet with an axial position of 350 mm and a radius of 20 mm.

Claims (6)

1. A device for measuring the magnetic field distribution of a superconducting magnet, characterized in that it comprises a measuring rod (1), a locking fixture (2), a guide sleeve (3), a mounting plate (4), an XY translation stage (5), Rotary table (6), conversion plate (7), probe fixture (8); Rotary table (6) is installed on the conversion board (7); XY translation table (5) is installed on the rotary table (6); Mounting plate ( 4) Fixed on the XY translation platform (5); the guide sleeve (3) is fixed on the installation plate (4); the locking fixture (2) is installed on the end surface of the guide sleeve (3); the measuring rod (1) passes through the lock The clamp (2) hole is inserted into the inner hole of the guide sleeve (3), and passes through the XY translation stage (5), the rotation stage (6) and the conversion plate (7); the probe fixture (8) is installed on the measuring rod (1) lower end. 2. The device for measuring the magnetic field distribution of a superconducting magnet according to claim 1, wherein said XY translation stage (5) comprises an X translation stage (9) and a Y translation stage (10); the X translation stage (9) on the Y translation platform (10), between the X direction guide rail (16) and the Y direction guide rail (18) is the shared guide rail substrate (17); the Y translation platform (10) side has a Y scale scale (11 ), the X scale scale (12) is arranged on the side of the X translation table (9); there are dovetail grooves on the X direction guide rail (16) and the Y direction guide rail (18), and one end of the dovetail groove is connected with the dovetail groove on the guide rail base (17) Cooperate, the other end of the dovetail groove is embedded in the guide rail slider (15). 3. The device for measuring the magnetic field distribution of superconducting magnets according to claim 1, characterized in that said rotating table (6) is an upper and lower split structure, and the upper table (22) is pressed on the lower table (23) , there is a sliding bearing (21) between the upper table (22) and the lower table (23) to support; the outer surface of the upper table (22) has an angular scale scale; the rotary table (6) can rotate 360° around the central axis of the rotary table (6) Rotation, manually rotating the turntable handle (20) can be rotated to any angular position; when the locking knob (19) is locked, the turntable (6) cannot rotate. 4. The device for measuring the magnetic field distribution of a superconducting magnet according to claim 1, characterized in that the guide sleeve (3) has three level adjustment screws (24) for adjusting the height of the level adjustment screws (24), Make slight adjustments to the verticality of the probe rod (1). 5. The device for measuring the magnetic field distribution of a superconducting magnet according to claim 1, characterized in that the probe clamp (8) is fixed on the lower end of the measuring rod (1); the probe clamp (8) includes a lock nut (26 ) and the probe chuck (27), the probe chuck (27) has a cross groove, and during the locking process of the lock nut (26), the cross groove of the probe chuck (27) is forced to close from the surrounding to the inside, realizing Automatic centering so that the axis of the probe coincides with the axis of the measuring rod (1). 6. The device for measuring the magnetic field distribution of a superconducting magnet according to any one of claims 1-5, wherein the guide rail slider (15) of the X direction and Y direction guide rails adopts an antifriction copper alloy; The bodies of the X translation stage (10) and the Y translation stage (9) are made of hard aluminum alloy; the upper table (22), the lower table (23) and the measuring rod (1) of the rotary table (6) are made of aluminum alloy; Table bearings and connecting parts are made of non-magnetic stainless steel, and the device has no ferromagnetic parts.

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