Superconducting solenoid multipole magnetic field analysis method and system

Abstract

The invention provides a superconducting solenoid multipolar magnetic field analysis method and system, and the method comprises the steps: measuring the magnetic field intensity of three-dimensional magnetic fields of different cross sections of a superconducting solenoid, the three-dimensional magnetic fields comprise a longitudinal magnetic field, a horizontal magnetic field and a vertical magnetic field, and calculating the magnetic field intensity of a first radial magnetic field through the horizontal magnetic field and the vertical magnetic field; calculating the magnetic field intensity of a second radial magnetic field of the superconducting solenoid according to the radial radius of the cross section of the superconducting solenoid and the longitudinal magnetic field, and judging whether the absolute value of the quotient of the magnetic field intensity of the first radial magnetic field and the second radial magnetic field is within a first preset range; judging whether three-dimensional magnetic fields of different cross sections of the superconducting solenoid need to be readjusted and measured or not according to a judgment result; the multi-pole field coefficient of the superconducting solenoid is calculated by using the horizontal magnetic field and the vertical magnetic field, and then the magnetic field intensity of the multi-pole field of the superconducting solenoid is calculated according to the multi-pole field coefficient, so that the problem that a simple and high-precision measurement and analysis method for solenoid magnetic axis and multi-pole field distribution is lacked at present is solved.

Description

Technical Field

[0001] The invention relates to the technical field of superconducting solenoid multipole magnetic field analysis, and in particular to a superconducting solenoid multipole magnetic field analysis method and system. Background Art

[0002] Superconducting solenoids play a vital role in high-precision applications such as particle accelerators and nuclear magnetic resonance imaging. The accuracy of their magnetic field directly affects the performance and application effects of the system. Traditional superconducting solenoid magnetic field analysis methods mainly focus on the axial magnetic field distribution under the condition that the magnetic axis does not have offset and tilt. These methods have achieved remarkable results in magnetic field analysis under ideal conditions. However, in practical applications, due to manufacturing errors, installation deviations, external interference and other factors, the offset and tilt of the magnetic axis are difficult to avoid. In this case, the magnetic field distribution of the superconducting solenoid will present complex multi-pole field characteristics, which will have a significant impact on the stability and accuracy of the system.

[0003] Although existing technologies can accurately predict and analyze magnetic fields under standard conditions, there are no simple, high-precision measurement and analysis methods for non-axisymmetric multipole field distributions in the presence of magnetic axis offset and tilt.

[0004] Therefore, the prior art needs to be further developed. Summary of the invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies and provide a superconducting solenoid multi-pole magnetic field analysis method and system to solve the problems existing in the prior art.

[0006] To achieve the above technical objectives, according to a first aspect of the present invention, the present invention provides a method for analyzing a multipolar magnetic field of a superconducting solenoid, comprising: S100, measuring the magnetic field strength of the three-dimensional magnetic field of different cross sections of the superconducting solenoid, wherein the three-dimensional magnetic field includes a longitudinal magnetic field, a horizontal magnetic field, and a vertical magnetic field, and calculating the magnetic field strength of the first radial magnetic field using the horizontal magnetic field and the vertical magnetic field; S200, calculating the magnetic field strength of the second radial magnetic field of the superconducting solenoid according to the radial radius of the cross section of the superconducting solenoid and the longitudinal magnetic field, and judging whether the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, and judging whether it is necessary to readjust and measure the three-dimensional magnetic field of different cross sections of the superconducting solenoid according to the judgment result; S300, calculating the multipole field coefficient of the superconducting solenoid using the horizontal magnetic field and the vertical magnetic field, and then calculating the magnetic field intensity of the multipole field of the superconducting solenoid according to the multipole field coefficient.

[0007] Specifically, the measuring of the magnetic field strength of the three-dimensional magnetic field of different cross sections of the superconducting solenoid includes: A three-dimensional Hall probe is used to scan along the mechanical center axis of the superconducting solenoid to measure the magnetic field strength of the three-dimensional magnetic field at different cross sections of the superconducting solenoid, wherein the three-dimensional magnetic field includes a longitudinal magnetic field, a horizontal magnetic field and a vertical magnetic field.

[0008] Specifically, the S100 further includes: The magnetic field strength of the longitudinal magnetic field of the superconducting solenoid and the current value passing through the superconducting solenoid are obtained, and whether there is a design defect of the superconducting solenoid is determined based on the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid and the current value passing through the superconducting solenoid.

[0009] Specifically, the method is as follows: Determine whether the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid is in direct proportion to the current value. If the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid is in direct proportion to the current value, it is determined that there is no defect in the design of the superconducting solenoid. If the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid is not in direct proportion to the current value, it is determined that there is a design defect in the superconducting solenoid and redesign or assembly is required.

[0010] Specifically, calculating the first radial magnetic field by using the horizontal magnetic field and the vertical magnetic field includes: The magnetic field strength of the radial magnetic field is obtained by combining the horizontal magnetic field and the vertical magnetic field of the superconducting solenoid, that is, the magnetic field strength of the first radial magnetic field , the specific calculation method is as follows: ; in, represents the magnetic field strength of the horizontal magnetic field of the superconducting solenoid, Represents the magnetic field strength of the vertical magnetic field of the superconducting solenoid.

[0011] Specifically, the step of calculating the magnetic field strength of the second radial magnetic field of the superconducting solenoid according to the radial radius of the cross section of the superconducting solenoid and the longitudinal magnetic field includes: The calculation method of the magnetic field strength of the second radial magnetic field of the superconducting solenoid is as follows: ; in, represents the magnetic field intensity of the second radial magnetic field, r represents the radial radius, z represents the distance along the axial direction, Represents the magnetic field strength of the longitudinal magnetic field.

[0012] Specifically, the determining whether the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, and determining whether it is necessary to readjust and measure the three-dimensional magnetic fields of different cross sections of the superconducting solenoid according to the determination result, includes: If the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, it is determined that there is no need to re-measure the three-dimensional magnetic field of different cross sections of the superconducting solenoid; If the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is not within the first preset range, it is necessary to remeasure the three-dimensional magnetic field of different cross sections of the superconducting solenoid until the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within the first preset range.

[0013] Specifically, the calculating of the multipole field coefficient of the superconducting solenoid by using the horizontal magnetic field and the vertical magnetic field includes: The multipole field coefficient of the superconducting solenoid is calculated using the measured magnetic field strengths of the horizontal magnetic field and the vertical magnetic field. The specific calculation method is as follows: =- ; =- Among them, X and Y represent the distances of the measurement points mapped to the x-axis and y-axis respectively. represents the magnetic field strength of the horizontal magnetic field of the superconducting solenoid 1, represents the magnetic field strength of the vertical magnetic field of the superconducting solenoid, represents the main transverse field coefficient of the superconducting solenoid 1, , They represent the positive dipole field coefficient and the slanted dipole field coefficient of the superconducting solenoid, , represent the positive quadrupole field coefficient and the oblique quadrupole field coefficient of the superconducting solenoid, respectively. , They represent the positive hexapole field coefficient and the slanted hexapole field coefficient of the superconducting solenoid respectively.

[0014] Specifically, the calculating the magnetic field strength of the multipole field of the superconducting solenoid according to the multipole field coefficient includes: According to the main transverse field coefficient , positive diode field coefficient , slant dipole field coefficient , the positive quadrupole field coefficient , oblique quadrupole field coefficient , positive hexapole field coefficient , oblique sextupole field coefficient , respectively calculate the main transverse field of superconducting solenoid 1 , positive diode field , oblique diode field , positive quadrupole field , oblique quadrupole field , positive hexapole field , oblique sextupole field , the specific calculation method is as follows: ; ; ; ; X ; ; ; Among them, X and Y represent the distances of the measurement points mapped to the x-axis and y-axis respectively. represents the unit vector of the x-axis, The unit vector representing the y-axis.

[0015] According to a second aspect of the present invention, there is provided a superconducting solenoid multipole magnetic field analysis system, comprising: An acquisition module is used to acquire the magnetic field strength of the three-dimensional magnetic field of different cross sections of the superconducting solenoid obtained by measurement, wherein the three-dimensional magnetic field includes a longitudinal magnetic field, a horizontal magnetic field and a vertical magnetic field; Control module: used to calculate the magnetic field strength of the first radial magnetic field using the horizontal magnetic field and the vertical magnetic field; or used to calculate the magnetic field strength of the second radial magnetic field of the superconducting solenoid according to the radial radius of the cross-section of the superconducting solenoid and the longitudinal magnetic field, and determine whether the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, and determine whether it is necessary to readjust and remeasure the three-dimensional magnetic field of different cross-sections of the superconducting solenoid based on the determination result; or used to calculate the multipole field coefficient of the superconducting solenoid using the horizontal magnetic field and the vertical magnetic field, and then calculate the magnetic field strength of the multipole field of the superconducting solenoid based on the multipole field coefficient.

[0016] Beneficial effects: The present invention provides a method for analyzing and fitting the multipole magnetic field of a superconducting solenoid, which solves the technical problem in the prior art of lacking a simple and high-precision analysis method for non-axisymmetric multipole field distribution. The method can quickly and accurately analyze the magnetic field of the solenoid and obtain the magnetic field strength of the multipole field of the solenoid, so that the multipole field can be compensated based on the measurement and analysis results, which is of vital importance for maintaining the stability of the multipole field and optimizing the performance of the multipole field. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flow chart of a superconducting solenoid multi-pole magnetic field analysis method provided in a specific embodiment of the present invention; Figure 2Schematic diagram of the system composition of the superconducting solenoid multipole magnetic field analysis system provided in a specific embodiment of the present invention; Figure 3 It is a schematic diagram of a simulation model of a solenoid and a quadrupole iron group provided in a specific embodiment of the present invention; Figure 4 It is a schematic diagram of a three-dimensional Hall probe scanning a superconducting solenoid magnetic field provided in a specific embodiment of the present invention; Wherein, the reference numerals of the above-mentioned drawings are as follows: 1. Superconducting solenoid; 2. Quadrupole iron model; 3. Hall probe; 4. Beam pipe; 5. Bracket; 6. Stepper motor; 8. Cross section. DETAILED DESCRIPTION In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings of the present invention. Based on the embodiments in this application, other similar embodiments obtained by ordinary technicians in this field without making creative work should all fall within the scope of protection of this application. In addition, the directional words mentioned in the following embodiments, such as "up", "down", "left", "right", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional words used are used to illustrate rather than limit the invention.

[0018] The present invention will be further described below in conjunction with the accompanying drawings and preferred embodiments.

[0019] See also Figure 1 This embodiment provides a method for analyzing a superconducting solenoid multipolar magnetic field, including: S100, measuring the magnetic field strength of the three-dimensional magnetic field of different cross sections 8 of the superconducting solenoid 1, wherein the three-dimensional magnetic field includes a longitudinal magnetic field, a horizontal magnetic field and a vertical magnetic field, and calculating the magnetic field strength of the first radial magnetic field by using the horizontal magnetic field and the vertical magnetic field; It should be noted here that a first preset range is pre-set before step S100. It is understandable that the present invention does not limit the specific value of the first preset range, as long as the superconducting solenoid multipole magnetic field analysis method proposed by the present invention can be applied.

[0020] Preferably, the present invention sets the first preset range to [0.98, 1.02]. The above setting can realize the evaluation of the accuracy of the measurement data. If the quotient is not within the preset range, it can be determined that re-measurement is required, which helps to improve the measurement accuracy and ensure the reliability of the magnetic field strength data of the radial magnetic field obtained, so as to better understand the radial characteristics of the magnetic field structure of the superconducting solenoid.

[0021] Specifically, the measuring of the magnetic field strength of the three-dimensional magnetic field of different cross sections 8 of the superconducting solenoid 1 includes: The three-dimensional Hall probe 3 is used to scan along the mechanical center axis of the superconducting solenoid 1 to measure the magnetic field strength of the three-dimensional magnetic field of different cross sections 8 of the superconducting solenoid 1 , wherein the three-dimensional magnetic field includes a longitudinal magnetic field, a horizontal magnetic field and a vertical magnetic field.

[0022] See also Figure 4 One end of the bracket 5 and the stepper motor 6 is connected to the three-dimensional Hall probe 3, and the other end is connected to the computer. The bracket plays a supporting and fixing role, providing a stable physical connection foundation for the stepper motor and the three-dimensional Hall probe 3, ensuring the stability of the entire device during operation. One end of the stepper motor 6 is connected to the bracket, and the other end is connected to the computer for data reading, and is connected to the three-dimensional Hall probe 3. The stepper motor 6, as a power source, can accurately control the position movement of the three-dimensional Hall probe. The three-dimensional Hall probe 3 changes its position within the stable frame constructed by the bracket through the connection with the stepper motor, and then detects the magnetic field related data. The detected data can be transmitted to the computer through the line connected to the bracket 5 and the stepper motor 6, and the three-dimensional Hall probe 3 is controlled to scan the three-dimensional magnetic field of different cross sections 8 of the superconducting solenoid 1 along the mechanical axis of the superconducting solenoid 1. The three-dimensional Hall probe 3 is a sensor that can measure the components of the magnetic field in three mutually perpendicular directions. In the magnetic field measurement of the superconducting solenoid 1, the magnetic field information at different cross sections 8 in the beam pipe 4 can be obtained by scanning along the mechanical center axis of the superconducting solenoid 1. For the superconducting solenoid 1, its magnetic field distribution has three-dimensional characteristics. The longitudinal magnetic field, the horizontal magnetic field and the vertical magnetic field are important components that describe its magnetic field state. When the three-dimensional Hall probe 3 moves along the mechanical center axis, it can accurately measure the magnetic field strength of the three-dimensional magnetic field at different cross sections 8. This measurement principle is based on the Hall effect. When current passes through the Hall element, a Hall voltage is generated in the direction perpendicular to the current and the magnetic field. Its magnitude is proportional to the magnetic field strength. By measuring the Hall voltage, the magnetic field strength in the corresponding direction can be obtained.

[0023] Specifically, the S100 further includes: The magnetic field strength of the longitudinal magnetic field of the superconducting solenoid 1 and the current value passing through the superconducting solenoid 1 are obtained, and whether there is a design defect of the superconducting solenoid 1 is determined based on the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid 1 and the current value passing through the superconducting solenoid 1.

[0024] Specifically, the method is as follows: Determine whether the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid 1 is in direct proportion to the current value. If the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid 1 is in direct proportion to the current value, it is determined that there is no defect in the design of the superconducting solenoid 1. If the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid 1 is not in direct proportion to the current value, it is determined that there is a design defect in the superconducting solenoid 1 and redesign or assembly is required.

[0025] It is understandable that, according to Ampere's loop law, for a long straight solenoid, the magnitude of its internal magnetic field in the axial direction is related to factors such as the current and the number of turns per unit length. Ideally, for the superconducting solenoid 1, based on Ampere's loop law, the axial magnetic field (longitudinal magnetic field) is proportional to the current. In the design stage of the superconducting solenoid 1, it is based on the ideal electromagnetic theory, such as the relationship described by the above Ampere's loop law. If it is found in the measurement that the peak magnetic field of the solenoid is not proportional to the current, it means that the actual situation deviates from the design expectation, and there may be an uneven distribution of the magnetic field inside the solenoid. Therefore, the axial magnetic field information of the superconducting solenoid 1 is obtained by measuring the change of the magnetic field intensity of the longitudinal magnetic field with the current value. The peak magnetic field of the solenoid is proportional to the current, and at least 3 current values ​​can be determined. If it is not proportional, it means that the solenoid has defects and needs to be redesigned or assembled.

[0026] Specifically, calculating the first radial magnetic field by using the horizontal magnetic field and the vertical magnetic field includes: The magnetic field strength of the radial magnetic field obtained by combining the horizontal magnetic field and the vertical magnetic field of the superconducting solenoid 1, that is, the magnetic field strength of the first radial magnetic field , the specific calculation method is as follows: ; (1) in, represents the magnetic field strength of the horizontal magnetic field of the superconducting solenoid 1, The magnetic field intensity of the vertical magnetic field of the superconducting solenoid 1 is shown.

[0027] It can be understood that from the perspective of the vector nature of the magnetic field, the magnetic field is a vector field, and the horizontal magnetic field and the vertical magnetic field generated by the superconducting solenoid 1 are vectors that exist independently of each other in space. Therefore, at a certain point in space, the effect of the two magnetic fields acting together can be represented by an equivalent magnetic field.

[0028] See also Figure 3 , Figure 3 Figure 1 is a superconducting solenoid 1 and a quadrupole iron model 2 added in the simulation, where x, y, z are laboratory coordinates, the origin is the center of the ideal solenoid, x', y', z' are the magnetic axes of the actual solenoid. Theoretically, the axial magnetic field of the solenoid has an extreme value on the magnetic axis, and the radial field is zero. Therefore, after measuring the magnetic field, the magnetic axis of the solenoid can be obtained based on these two characteristics.

[0029] S200, calculating the magnetic field strength of the second radial magnetic field of the superconducting solenoid 1 according to the radial radius of the cross section 8 of the superconducting solenoid 1 and the longitudinal magnetic field, and judging whether the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, and judging whether it is necessary to readjust and measure the three-dimensional magnetic field of different cross sections 8 of the superconducting solenoid 1 according to the judgment result.

[0030] Furthermore, calculating the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field and comparing it with the first preset range is a means of evaluating the stability and uniformity of the magnetic field of the superconducting solenoid 1. If this quotient is within the preset range, it means that the relationship between the different radial magnetic fields of the superconducting solenoid 1 is as expected, and the distribution of its magnetic field is relatively stable and uniform. Based on the judgment result, it is decided whether to re-measure the three-dimensional magnetic field of different cross-sections 8 of the superconducting solenoid 1. If the quotient is not within the preset range, this means that the magnetic field of the superconducting solenoid 1 may be abnormal, such as uneven magnetic field distribution or local interference. At this time, re-measuring the three-dimensional magnetic field helps to find the problem in more detail, further improving the accuracy and reliability of the measurement data.

[0031] Specifically, the step of calculating the magnetic field strength of the second radial magnetic field of the superconducting solenoid 1 according to the radial radius of the cross section 8 of the superconducting solenoid 1 and the longitudinal magnetic field includes: The calculation method of the magnetic field strength of the second radial magnetic field of the superconducting solenoid 1 is as follows: ; (2) in, represents the magnetic field intensity of the second radial magnetic field, r represents the radial radius, z represents the distance along the axial direction, Represents the magnetic field strength of the longitudinal magnetic field.

[0032] Specifically, the determining whether the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, and determining whether it is necessary to readjust and measure the three-dimensional magnetic field of different cross sections 8 of the superconducting solenoid 1 according to the determination result, includes: If the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, it is determined that there is no need to re-measure the three-dimensional magnetic field of different cross sections 8 of the superconducting solenoid 1; If the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is not within the first preset range, it is necessary to remeasure the three-dimensional magnetic field of different cross sections of the superconducting solenoid 1 until the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within the first preset range.

[0033] It is understandable that the present invention sets the first preset range to [0.98, 1.02], which helps to improve the measurement accuracy and ensure the reliability of the magnetic field strength data of the obtained radial magnetic field, so as to better understand the radial characteristics of the magnetic field structure of the superconducting solenoid 1.

[0034] Furthermore, when the magnetic axis is not offset or tilted, the first radial magnetic field and the second radial magnetic field are completely equal. When the two magnetic field intensities are obviously different, that is, a large error occurs, it means that the magnetic axis is offset or tilted too much or there is a problem with the design and processing, and further adjustment of the alignment or optimization of the design and processing is required. Otherwise, the multipole field component measured is very large, and the impact on actual use cannot be compensated. It is determined whether it is necessary to re-measure the three-dimensional magnetic field of different cross sections 8 of the superconducting solenoid 1. The main purpose is to measure and analyze the multipole field caused by the deviation under the condition of ensuring high-precision alignment, and make compensation accordingly. When it is found that there is a problem with the installation or design and processing, that is, there is an obvious error between the first radial field and the second radial field, it needs to be corrected in time.

[0035] S300, calculating the multipole field coefficient of the superconducting solenoid 1 by using the horizontal magnetic field and the vertical magnetic field, and then calculating the magnetic field intensity of the multipole field of the superconducting solenoid 1 according to the multipole field coefficient.

[0036] Specifically, the calculation of the multipole field coefficient of the superconducting solenoid 1 by using the horizontal magnetic field and the vertical magnetic field includes: The multipole field coefficient of the superconducting solenoid 1 is calculated using the measured magnetic field strengths of the horizontal magnetic field and the vertical magnetic field. The specific calculation method is as follows: =- ; (3) =- (4) Among them, X and Y represent the distances of the measurement points mapped to the x-axis and y-axis respectively. represents the magnetic field strength of the horizontal magnetic field of the superconducting solenoid 1, represents the magnetic field strength of the vertical magnetic field of the superconducting solenoid 1, represents the main transverse field coefficient of the superconducting solenoid 1, , They represent the positive dipole field coefficient and the slanted dipole field coefficient of the superconducting solenoid 1, , represent the positive quadrupole field coefficient and the oblique quadrupole field coefficient of the superconducting solenoid 1, respectively. , They represent the positive hexapole field coefficient and the slanted hexapole field coefficient of the superconducting solenoid 1 respectively.

[0037] See also Figure 4The present invention measures the magnetic field strength of the horizontal magnetic field and the vertical magnetic field at multiple groups of measurement points in each cross section, and performs polynomial expansion on the magnetic field strength of the horizontal magnetic field and the vertical magnetic field, and obtains each multipole field coefficient by fitting, so as to quickly analyze the solenoid magnetic field and further obtain the multipole field size of the solenoid.

[0038] Furthermore, the main transverse field is a main component of the magnetic field of the superconducting solenoid 1 in the horizontal or vertical direction, reflecting the main magnetic field distribution in the transverse plane; the dipole field is a field with a specific magnetic field distribution pattern, and the positive dipole field and the slanted dipole field are different forms of the dipole field. The existence of the dipole field will cause the magnetic field to produce a distribution effect similar to a dipole in space; the quadrupole field is a more complex magnetic field distribution form than the dipole field. The positive quadrupole field and the slanted quadrupole field have a specific spatial magnetic field gradient distribution, which can focus or defocus the particle beam; the sextupole field is a higher-order magnetic field distribution form. The positive sextupole field and the slanted sextupole field have a more complex magnetic field spatial distribution, which is mainly used for high-order correction of the particle beam. In addition, the polynomial expansion of the magnetic field intensity of the horizontal magnetic field and the vertical magnetic field also includes the octupole field, the decapole field, etc.

[0039] Specifically, the calculating the magnetic field strength of the multipole field of the superconducting solenoid 1 according to the multipole field coefficient includes: According to the main transverse field coefficient , positive diode field coefficient , slant dipole field coefficient , the positive quadrupole field coefficient , oblique quadrupole field coefficient , positive hexapole field coefficient , oblique sextupole field coefficient , respectively calculate the main transverse field of superconducting solenoid 1 , positive diode field , oblique diode field , positive quadrupole field , oblique quadrupole field , positive hexapole field , oblique sextupole field , the specific calculation method is as follows: ; (5) ; (6) ; (7) ; (8) X ; (9) ; (10) ; (11) Among them, X and Y represent the distances of the measurement points mapped to the x-axis and y-axis respectively. represents the unit vector of the x-axis, The unit vector representing the y-axis.

[0040] It can be understood that the present invention can quickly analyze the solenoid magnetic field, obtain the size of the solenoid multipole field and compensate for the multipole field based on the measurement and analysis results through the analysis and fitting method of the superconducting solenoid multipole field. The compensation can be mainly divided into two ways. One is to add an additional coil inside the solenoid coil and apply a suitable current to generate a multipole field opposite to the multipole field of the solenoid coil; the other is to add a coil outside the solenoid coil and apply a suitable current to generate a multipole field opposite to the multipole field of the solenoid coil.

[0041] See also Figure 4 The working principle of the present invention is described below by using specific examples: The implementation steps of the technical solution of the present invention are as follows: Step 1: Assemble the superconducting solenoid 1 module; Step 2: Control the three-dimensional Hall probe 3 to scan the magnetic field of the superconducting solenoid 1 along the mechanical axis of the superconducting solenoid 1, such as Figure 4 As shown, the three-dimensional magnetic field of different cross sections 8 in the beam pipe 4 is measured; Step 3: According to equation (2), the transverse magnetic field of each section of the superconducting solenoid 1 and the magnetic field strength of the second magnetic field are analyzed to obtain the magnetic axis equation; according to equation group (3) and equation (4), the transverse magnetic field of each section of the superconducting solenoid 1 is analyzed to obtain the multipole field coefficient; according to equation group (5)-(11), the size and distribution of each multipole field of the superconducting solenoid 1 are calculated. It should be noted here that the present embodiment provides a method for analyzing and fitting the multipole magnetic field of a superconducting solenoid 1, which solves the technical problem in the prior art of lacking a simple and high-precision analysis method for non-axisymmetric multipole field distribution. This method can quickly and accurately analyze the solenoid magnetic field and obtain the magnetic field strength of the solenoid's multipole field, so that the multipole field can be compensated based on the measurement and analysis results, which is of vital importance for maintaining the stability of the multipole field and optimizing the performance of the multipole field.

[0042] See also Figure 2 This embodiment provides a superconducting solenoid 1 multi-pole magnetic field analysis system, the system comprising: An acquisition module 100 is used to acquire the magnetic field strength of the three-dimensional magnetic field of different cross sections 8 of the superconducting solenoid 1 obtained by measurement, wherein the three-dimensional magnetic field includes a longitudinal magnetic field, a horizontal magnetic field and a vertical magnetic field; Control module 200: used to calculate the magnetic field strength of the first radial magnetic field using the horizontal magnetic field and the vertical magnetic field; or used to calculate the magnetic field strength of the second radial magnetic field of the superconducting solenoid 1 according to the radial radius of the cross section 8 of the superconducting solenoid 1 and the longitudinal magnetic field, and determine whether the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, and determine whether it is necessary to readjust and remeasure the three-dimensional magnetic field of different cross sections 8 of the superconducting solenoid 1 based on the determination result; or used to calculate the multipole field coefficient of the superconducting solenoid 1 using the horizontal magnetic field and the vertical magnetic field, and then calculate the magnetic field strength of the multipole field of the superconducting solenoid 1 based on the multipole field coefficient.

[0043] It should be noted here that the present embodiment provides a multipole magnetic field analysis system for a superconducting solenoid, which solves the technical problem in the prior art of the lack of a simple, high-precision analysis method for non-axisymmetric multipole field distribution. The system can quickly and accurately analyze the solenoid magnetic field and obtain the magnetic field strength of the solenoid's multipole field, so that the multipole field can be compensated based on the measurement and analysis results, which is of vital importance for maintaining the stability of the multipole field and optimizing the performance of the multipole field.

[0044] The various technical features described above can be combined arbitrarily. Although all possible combinations of these technical features are not described, any combination of these technical features should be considered to be covered by this specification as long as there is no contradiction in such combination.

[0045] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for analyzing a superconducting solenoid multipole magnetic field, characterized in that: include: S100, measuring the magnetic field strength of the three-dimensional magnetic field of different cross sections (8) of the superconducting solenoid (1), wherein the three-dimensional magnetic field includes a longitudinal magnetic field, a horizontal magnetic field and a vertical magnetic field, and calculating the magnetic field strength of the first radial magnetic field using the horizontal magnetic field and the vertical magnetic field; S200, calculating the magnetic field strength of the second radial magnetic field of the superconducting solenoid (1) according to the radial radius of the cross section (8) of the superconducting solenoid (1) and the longitudinal magnetic field, and judging whether the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, and judging whether it is necessary to readjust and measure the three-dimensional magnetic field of different cross sections (8) of the superconducting solenoid (1) according to the judgment result; S300: Calculate the multipole field coefficient of the superconducting solenoid (1) using the horizontal magnetic field and the vertical magnetic field, and then calculate the magnetic field intensity of the multipole field of the superconducting solenoid (1) according to the multipole field coefficient.

2. The superconducting solenoid multi-pole magnetic field analysis method according to claim 1, characterized in that: The method of measuring the magnetic field strength of the three-dimensional magnetic field of different cross sections (8) of the superconducting solenoid (1) comprises: A three-dimensional Hall probe (3) is used to scan along the mechanical center axis of the superconducting solenoid (1) to measure the magnetic field intensity of the three-dimensional magnetic field at different cross sections (8) of the superconducting solenoid (1), wherein the three-dimensional magnetic field includes a longitudinal magnetic field, a horizontal magnetic field and a vertical magnetic field.

3. The superconducting solenoid multipole magnetic field analysis method according to claim 2, characterized in that: The S100 further includes: The magnetic field strength of the longitudinal magnetic field of the superconducting solenoid (1) and the current value passing through the superconducting solenoid (1) are obtained, and it is determined whether there is a design defect of the superconducting solenoid (1) based on the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid (1) and the current value passing through the superconducting solenoid (1).

4. The superconducting solenoid multi-pole magnetic field analysis method according to claim 3, characterized in that: The method is specifically as follows: Determining whether the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid (1) is in direct proportion to the current value; if the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid (1) is in direct proportion to the current value, then determining that there is no defect in the design of the superconducting solenoid (1); If the magnetic field strength of the longitudinal magnetic field of the superconducting solenoid (1) is not in direct proportion to the current value, it is determined that there is a design defect in the superconducting solenoid (1), and redesign or assembly is required.

5. The superconducting solenoid multi-pole magnetic field analysis method according to claim 1, characterized in that: The calculating the first radial magnetic field by using the horizontal magnetic field and the vertical magnetic field comprises: The magnetic field strength of the radial magnetic field obtained by combining the horizontal magnetic field and the vertical magnetic field of the superconducting solenoid (1), that is, the magnetic field strength of the first radial magnetic field , the specific calculation method is as follows: ； in, represents the magnetic field strength of the horizontal magnetic field of the superconducting solenoid (1), It represents the magnetic field strength of the vertical magnetic field of the superconducting solenoid (1).

6. The superconducting solenoid multi-pole magnetic field analysis method according to claim 5, characterized in that: The method of calculating the magnetic field intensity of the second radial magnetic field of the superconducting solenoid (1) according to the radial radius of the cross section (8) of the superconducting solenoid (1) and the longitudinal magnetic field comprises: The calculation method of the magnetic field strength of the second radial magnetic field of the superconducting solenoid (1) is as follows: ; in, represents the magnetic field intensity of the second radial magnetic field, r represents the radial radius, z represents the distance along the axial direction, Represents the magnetic field strength of the longitudinal magnetic field.

7. The superconducting solenoid multi-pole magnetic field analysis method according to claim 6, characterized in that: The step of judging whether the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, and judging whether it is necessary to readjust and measure the three-dimensional magnetic fields of different cross sections (8) of the superconducting solenoid (1) according to the judging result, comprises: If the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, it is determined that there is no need to re-measure the three-dimensional magnetic field of different cross sections (8) of the superconducting solenoid (1); If the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is not within the first preset range, it is necessary to re-measure the three-dimensional magnetic fields of different cross sections (8) of the superconducting solenoid (1) until the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within the first preset range.

8. The superconducting solenoid multi-pole magnetic field analysis method according to claim 7, characterized in that: The method of calculating the multipole field coefficient of the superconducting solenoid (1) by using the horizontal magnetic field and the vertical magnetic field comprises: The multipole field coefficient of the superconducting solenoid (1) is calculated using the measured magnetic field strengths of the horizontal magnetic field and the vertical magnetic field. The specific calculation method is as follows: =- ; =- Among them, X and Y represent the distances of the measurement points mapped to the x-axis and y-axis respectively. represents the magnetic field strength of the horizontal magnetic field of the superconducting solenoid (1), represents the magnetic field strength of the vertical magnetic field of the superconducting solenoid (1), represents the main transverse field coefficient of the superconducting solenoid (1), , denote the positive dipole field coefficient and the slanted dipole field coefficient of the superconducting solenoid (1), respectively. , denote the positive quadrupole field coefficient and the oblique quadrupole field coefficient of the superconducting solenoid (1), respectively. , They represent the positive sextupole field coefficient and the slanted sextupole field coefficient of the superconducting solenoid (1) respectively.

9. The superconducting solenoid multi-pole magnetic field analysis method according to claim 8, characterized in that: Calculating the magnetic field strength of the multipole field of the superconducting solenoid (1) according to the multipole field coefficient comprises: According to the main transverse field coefficient , positive diode field coefficient , slant dipole field coefficient , the positive quadrupole field coefficient , oblique quadrupole field coefficient , positive hexapole field coefficient , oblique sextupole field coefficient , respectively calculate the main transverse field of the superconducting solenoid (1) , positive diode field , oblique diode field , positive quadrupole field , oblique quadrupole field , positive hexapole field , oblique sextupole field , the specific calculation method is as follows: ； ； ； ； X ； ; ； Among them, X and Y represent the distances of the measurement points mapped to the x-axis and y-axis respectively. represents the unit vector of the x-axis, The unit vector representing the y-axis.

10. A superconducting solenoid multi-pole magnetic field analysis system, characterized in that: include: An acquisition module (100): used to acquire the magnetic field strength of the three-dimensional magnetic field of different cross sections (8) of the superconducting solenoid (1) obtained by measurement, wherein the three-dimensional magnetic field includes a longitudinal magnetic field, a horizontal magnetic field and a vertical magnetic field; A control module (200): used to calculate the magnetic field strength of a first radial magnetic field using the horizontal magnetic field and the vertical magnetic field; or used to calculate the magnetic field strength of a second radial magnetic field of the superconducting solenoid (1) based on the radial radius of a cross section (8) of the superconducting solenoid (1) and the longitudinal magnetic field, and to determine whether the absolute value of the quotient of the magnetic field strengths of the first radial magnetic field and the second radial magnetic field is within a first preset range, and to determine whether it is necessary to readjust and measure the three-dimensional magnetic field of different cross sections of the superconducting solenoid (1) based on the determination result; or used to calculate the multipole field coefficient of the superconducting solenoid (1) using the horizontal magnetic field and the vertical magnetic field, and then calculate the magnetic field strength of the multipole field of the superconducting solenoid (1) based on the multipole field coefficient.

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