Method and apparatus for correcting the magnetic field quality of a superconducting undulator

Abstract

The application discloses a superconducting wave oscillator magnetic field quality correction method and device. The method determines a first correction position and a second correction position which need to be corrected according to the current magnetic field distribution of the superconducting wave oscillator, and reduces or increases the current at the first correction position by connecting a first correction current between the first input terminal and the first output terminal of the first correction position, so as to change the peak magnetic field of the adjacent two pole pieces at the first correction position, and the phase error of the superconducting wave oscillator can be optimized. Meanwhile, the application also connects a second correction current between the second input terminal and the second output terminal of the second correction position, so that the current in the wire slot at the second correction position contributes more to the magnetic field of the pole piece close to the half-layer coil than to the magnetic field of the pole piece far from the half-layer coil, thereby increasing the correction amount of a magnetic field integral, and the integral magnetic field is optimized.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of low-temperature superconducting technology, and in particular to a method and device for correcting the magnetic field quality of a superconducting undulator. BACKGROUND

[0002] Undulators are mainly used in advanced particle accelerator-based light sources or free electron laser devices. By generating a periodically varying magnetic field in the direction of the beam trajectory, the electron beam produces transverse oscillation when passing through, thereby radiating photons. These devices have greatly promoted the development of fields such as optics, condensed matter physics, materials and chemistry under extreme conditions, and life sciences. Superconducting undulators are a new hot research direction in the field of undulators, which can generate higher peak magnetic fields in shorter periods, thereby enhancing the brightness and quality of radiation.

[0003] The current manufacturing process of a superconducting undulator is as follows: a superconducting wire is wound around an iron core. After winding in one slot, the winding direction is changed by a reversing structure to continue winding in the next slot, thereby realizing current reversal. The two magnets are placed opposite each other, thereby forming a periodically varying magnetic field on the central axis of the magnetic gap. The formation of the slot is achieved by inserting pole pieces and insulating materials into the iron core. After the superconducting coil is wound, it usually needs to be impregnated to solidify the coil to resist electromagnetic forces during excitation, thereby improving the excitation efficiency and memory effect of the magnet.

[0004] In the manufacturing process of a superconducting undulator, factors such as material non-uniformity, machining errors of various parts, and assembly errors of pole pieces and iron cores can change the magnetic field quality of the superconducting undulator, thereby affecting the use of the superconducting undulator. SUMMARY

[0005] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a method for correcting the magnetic field quality of a superconducting undulator.

[0006] The first aspect provides a method for correcting the magnetic field quality of a superconducting undulator, characterized in that the method comprises:

[0007] obtaining a magnetic field distribution of the superconducting undulator at a current time;

[0008] determining a first correction position and a second correction position according to the magnetic field distribution at the current time;

[0009] accessing a first correction current between a first incoming line end and a first outgoing line end of the first correction position, and accessing a second correction current between a second incoming line end and a second outgoing line end of the second correction position, the first incoming line end and the second outgoing line end being set according to a coil wound on all the number of turns on the first correction position, the second incoming line end and the second outgoing line end being set according to a coil wound on the second correction position away from the outermost layer of the coil surface.

[0010] The correction method for the magnetic field quality of the superconducting undulator provided in the application determines the first correction position and the second correction position that need to be corrected according to the magnetic field distribution of the superconducting undulator at the current time, and reduces or increases the current at the first correction position by accessing the first correction current between the first incoming line end and the first outgoing line end of the first correction position, locally changes the current in the slot without affecting the operation of the magnet, thereby changing the peak magnetic field of the adjacent pole pieces at the first correction position, and the purpose of optimizing the phase error of the superconducting undulator can also be achieved. Meanwhile, the application also makes the current in the slot at the second correction position contribute more to the magnetic field at the pole piece close to the half-layer coil than to the magnetic field at the pole piece away from the half-layer coil by accessing the second correction current between the second incoming line end and the second outgoing line end of the second correction position, thereby increasing the correction amount of the integral magnetic field, and the purpose of optimizing the integral magnetic field is achieved.

[0011] The second aspect provides a correction device for the magnetic field quality of a superconducting undulator, and the device comprises:

[0012] The acquisition module is configured to acquire the magnetic field distribution of the superconducting undulator at the current time.

[0013] The determination module is configured to determine the first correction position and the second correction position according to the magnetic field distribution at the current time.

[0014] The wiring module is configured to access a first correction current between a first incoming line end and a first outgoing line end of the first correction position, and access a second correction current between a second incoming line end and a second outgoing line end of the second correction position, the first incoming line end and the second outgoing line end being set according to a coil wound on all the number of turns on the first correction position, the second incoming line end and the second outgoing line end being set according to a coil wound on the second correction position away from the outermost layer of the coil surface. BRIEF DESCRIPTION OF DRAWINGS

[0015] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0016] Figure 1A structural schematic diagram of a superconducting undulator provided by the present application;

[0017] Figure 2 A step flow chart of a magnetic field quality correction method of a superconducting undulator provided by the present application;

[0018] Figure 3 A circuit diagram of reverse access to a first correction current provided by the present application;

[0019] Figure 4 A circuit diagram of forward access to a first correction current provided by the present application;

[0020] Figure 5 A circuit diagram of forward access to a second correction current provided by the present application;

[0021] Figure 6 A circuit diagram of reverse access to a second correction current provided by the present application;

[0022] Figure 7 A structural schematic diagram of a magnetic field quality correction device of a superconducting undulator provided by the present application.

[0023] BRIEF DESCRIPTION OF DRAWINGS

[0024] 10. superconducting undulator; 101, first coil array; 102, second coil array; 1011, core; 1012, pole piece; 1013, slot. DETAILED DESCRIPTION

[0025] The present application will be further described below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, and are not a limitation on the application. In addition, it should be noted that, for ease of description, only the parts related to the application are shown in the drawings.

[0026] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0027] Before the correction method of the magnetic field quality of a superconducting undulator provided by the present application is described, the structure of the superconducting undulator is first described.

[0028] As shown in FIG. 1, the superconducting undulator comprises a first coil array 101 and a second coil array 102. The first coil array 101 comprises a core 1011 and a plurality of pole pieces 1012. The core 1011 is arranged in a hollow structure, and the pole pieces 1012 are arranged on the core 1011. The second coil array 102 comprises a plurality of slots 1013. The slots 1013 are arranged on the core 1011. Figure 1As shown, the superconducting undulator 10 includes two rows of coil arrays (a first coil array 101 and a second coil array 102) that are longitudinally spaced and arranged in parallel. Each row of the coil array includes an iron core 1011 and a plurality of pole pieces 1012 axially spaced apart on the iron core 1011. Since the pole pieces 1012 are inserted into the surface of the iron core 1011, the outer surface of the pole pieces 1012 away from the surface of the iron core 1011 is higher than the surface of the iron core 1011, so that a groove is formed between adjacent pole pieces 1012 and on the surface of the iron core 1011. The groove is used for winding a superconducting wire, so here we call the groove a wire slot 1013. A plurality of wire slots 1013 are formed between the plurality of pole pieces 1012. After winding a wire slot 1013, a single superconducting wire changes the winding direction through a commutation structure and continues to wind in the next wire slot 1013, thereby realizing the commutation of the current. It should be noted here that n turns of coil are wound in each wire slot 1013 , where n is a natural number, for example, ranging from 5 to 120.

[0029] The two coil arrays are placed opposite each other up and down, and then after power is turned on, the central axes of the two coil arrays form a periodically changing magnetic field.

[0030] After the superconducting wire is wound, it typically undergoes an impregnation process to solidify the coils and resist the electromagnetic forces during the excitation process, thereby improving the magnet's excitation efficiency and memory effect. Various errors are introduced during the manufacturing process of the superconducting undulator 10, such as material inhomogeneity, machining errors of various components, and assembly errors between the pole piece 1012 and the core 1011. These errors can alter the quality of the magnetic field. For example, a worsening phase error can reduce the coherence of the light emitted by the undulator, while increases in the primary and secondary integrals of the magnetic field can affect the motion of the beam.

[0031] However, at this time, the coils on the superconducting undulator 10 have been impregnated and solidified, and thus cannot be subjected to secondary processing, which affects the use of the superconducting undulator 10 .

[0032] Based on the above problems, the present application provides a method for calibrating the magnetic field quality of a superconducting undulator 10, which can calibrate the magnetic field quality of an already formed superconducting undulator 10 without having to improve the internal structure of the already formed superconducting undulator 10. Figure 2 As shown, the method includes the following steps:

[0033] Step S20, obtaining the magnetic field distribution of the superconducting undulator 10 at the current moment;

[0034] The superconducting undulator 10 is any superconducting undulator 10 that needs to be calibrated for magnetic field quality, and the superconducting undulator 10 is a superconducting undulator 10 manufactured according to the above method. The current time is the initial time for calibration.

[0035] The central axis of the two coil arrays of the superconducting undulator 10 can form a periodically varying magnetic field after energization. Since the number of turns of the coils wound in each slot 1013 of the superconducting undulator 10 is usually the same, the coils wound in the same row of slots 1013 are the same superconducting coil, and the two coil arrays are also completely the same, so the magnetic field distribution obtained after the magnetic field scanning of the superconducting undulator 10 should show a certain rule, for example, the magnetic field distribution is a sinusoidal curve distribution, a square wave distribution, a sawtooth wave distribution, etc., so the magnetic field distribution can be used as data support for magnetic field quality correction. For example, the present application can determine that the superconducting undulator 10 needs to be corrected in the case that the magnetic field distribution does not show a certain rule.

[0036] For example, when it is necessary to obtain the magnetic field distribution of the superconducting undulator 10 at the current time, the superconducting undulator 10 under energization can be scanned by a Hall probe to obtain corresponding data. The magnetic field distribution map can be drawn manually by the magnetic field scanning data provided by the Hall probe, or by a computer device according to the magnetic field scanning data provided by the Hall probe. The present application does not limit this.

[0037] Step S30, determining a first correction position and a second correction position according to the magnetic field distribution at the current time;

[0038] The magnetic field distribution at the current time can be represented by a magnetic field distribution curve. For example, it can be represented by a distribution curve of the magnetic field along the z-axis, a distribution curve of the magnetic field along the x-axis, a distribution curve of the magnetic field along the y-axis, etc. Therefore, the magnetic field distribution at the current time is, for example, a sinusoidal curve, a cosine curve, a square wave, a sawtooth wave, etc. The first correction position can be used to correct the peak magnetic field of the superconducting undulator 10. The second correction position can be used to correct the integrated magnetic field of the superconducting undulator 10.

[0039] If the magnetic field distribution at the current time is a sinusoidal curve, the first correction position can be determined according to the peak value and the trough value of the sinusoidal curve. For example, the first correction position can be determined by the curve part of the sinusoidal curve corresponding to the slot 1013 where the peak value is higher than the adjacent peak value; the first correction position can be determined by the curve part of the sinusoidal curve corresponding to the slot 1013 where the peak value is higher than the average peak value; the first correction position can be determined by the curve part of the sinusoidal curve corresponding to the slot 1013 where the trough value is lower than the adjacent trough value; the first correction position can be determined by the curve part of the sinusoidal curve corresponding to the slot 1013 where the trough value is lower than the average trough value, etc. The present application does not limit this.

[0040] In addition, if the magnetic field distribution at the current moment is a sinusoidal curve, the second correction position can be determined according to the slope of the sinusoidal curve, the second-order integral along the beam direction, etc.

[0041] The first correction position and the second correction position can be the same slot 1013 or different slots 1013, which is determined according to the determination rule.

[0042] In an optional embodiment, the present application can be that, in the case that there is a curve part in which the peak value is higher or lower than the average peak value in the sinusoidal curve, the slot 1013 corresponding to the curve part in which the peak value is higher or lower than the average peak value is determined as the first correction position.

[0043] Here, the peak value can refer to a peak or a trough, that is, as long as there is a curve part in which the peak value is higher or lower than the average peak value in the sinusoidal curve, the slot 1013 corresponding to the curve part in which the peak value is higher or lower than the average peak value is determined as the first correction position, and the peak value can be located at the peak or the trough.

[0044] In an optional embodiment, the present application can be that, in the case that a positive inflection point or a negative inflection point appears after the second-order integral along the beam direction of the sinusoidal curve, the slot 1013 corresponding to the curve part in which the positive inflection point or the negative inflection point appears is determined as the second correction position.

[0045] In step S40, a first correction current is connected between the first input terminal and the first output terminal at the first correction position, and a second correction current is connected between the second input terminal and the second output terminal at the second correction position, the first input terminal and the second output terminal are set according to the coils wound on all the turns at the first correction position, and the second input terminal and the second output terminal are set according to the coils wound on the outermost layer of the coils at the second correction position.

[0046] In the process of manufacturing the superconducting undulator 10, in order to facilitate subsequent correction, a first input terminal and a first output terminal can be provided for all the turns of the coils in each slot 1013 of the superconducting undulator 10, and a second input terminal and a second output terminal can be provided for the coils wound on the outermost layer in each slot 1013. Here, in order to facilitate the distinction, the first input terminal and the first output terminal provided for all the turns of the coils in each slot 1013 of the superconducting undulator 10 are called the first input terminal and the first output terminal, and the second input terminal and the second output terminal provided for the coils wound on the outermost layer in each slot 1013 are called the second input terminal and the second output terminal.

[0047] The present application can be to perform corresponding correction operations according to the first input terminal and the first output terminal of the first correction position to realize the correction of the peak magnetic field of the superconducting undulator 10, and to perform corresponding correction operations according to the second input terminal and the second output terminal of the second correction position to realize the correction of the integrated magnetic field of the superconducting undulator 10.

[0048] It can be understood that a peak value higher than the average peak value indicates that the current at that location is larger than that at other locations, so we need to subtract the current at that location to eliminate the situation where the peak value is higher than the average peak value. Similarly, a peak value lower than the average peak value indicates that the current at that location is smaller than that at other locations, so we need to add the current at that location to eliminate the situation where the peak value is lower than the average peak value.

[0049] In an optional embodiment, the present application may perform a current subtraction operation for the first correction position by the following method:

[0050] A first correction current is reversely connected between the first input terminal and the first output terminal at the first correction position.

[0051] The present application may be to perform current addition operation for the first correction position by the following method:

[0052] A first correction current is connected in a forward direction between the first input terminal and the first output terminal at the first correction position.

[0053] In another optional embodiment, Figure 3 As shown, the first correction current is reversely connected between the first input terminal and the first output terminal at the first correction position, and the following operations may be performed:

[0054] The first input terminal of the first correction position is connected to the negative pole of the first power supply through the first superconducting wire and the first current lead, and the first output terminal of the first correction position is connected to the positive pole of the first power supply through the second superconducting wire and the second current lead.

[0055] In another optional embodiment, Figure 4 As shown, the first correction current is connected in a forward direction between the first input terminal and the first output terminal at the first correction position, and the following operations may be performed:

[0056] The first input terminal of the first correction position is connected to the positive pole of the first power supply through the first superconducting wire and the first current lead, and the first output terminal of the first correction position is connected to the negative pole of the first power supply through the second superconducting wire and the second current lead.

[0057] The first superconducting wire and the second superconducting wire can be welded in the corresponding first wire-in end and the first wire-out end in advance. When the magnetic field quality correction is needed, a power supply is connected to the two superconducting wires in a forward direction or a reverse direction. It can be understood that the forward connection of the first power supply increases the current at the first correction position, and the reverse connection of the first power supply reduces the current at the first correction position. In addition, the first wire-in end and the first wire-out end are led out to the cryostat through two current leads, which does not affect the normal operation of the superconducting oscillator 10.

[0058] As for the increase or decrease of the current, it can be determined by continuous debugging. For example, at the first time, a first current is output by the first power supply, and then the magnetic field distribution of the superconducting oscillator 10 is obtained. If the peak value corresponding to the first correction position in the magnetic field distribution is still less than the average peak value, a second current greater than the first current is output by the first power supply, and then the magnetic field distribution of the superconducting oscillator 10 is obtained. It is continued to determine whether the current output by the first power supply needs to be adjusted according to the magnetic field distribution of the superconducting oscillator 10 until the desired result is obtained.

[0059] The above method can only change the peak magnetic field at the adjacent two pole pieces 1012 of the superconducting oscillator 10 and optimize the phase error of the superconducting oscillator 10. If the purpose of optimizing the integral magnetic field of the superconducting oscillator 10 is to be achieved, the second wire-in end and the second wire-out end need to be used.

[0060] In an optional embodiment, the second correction current is connected in a reverse direction between the second wire-in end and the second wire-out end at the second correction position when the positive inflection point appears after the second-order integration of the corresponding sinusoidal curve along the beam direction at the second correction position. Thus, the contribution of the current in the slot 1013 to the magnetic field at the pole piece 1012 close to the outermost coil is greater than the contribution to the magnetic field at the pole piece 1012 far from the outermost coil, thereby increasing the correction amount of one magnetic field integration and achieving the purpose of optimizing the integral magnetic field.

[0061] In another optional embodiment, the second correction current is connected in a forward direction between the second wire-in end and the second wire-out end at the second correction position when the negative inflection point appears after the second-order integration of the corresponding sinusoidal curve along the beam direction at the second correction position. Thus, the contribution of the current in the slot 1013 to the magnetic field at the pole piece 1012 close to the outermost coil is less than the contribution to the magnetic field at the pole piece 1012 far from the outermost coil, thereby reducing the correction amount of one magnetic field integration and achieving the purpose of optimizing the integral magnetic field.

[0062] In yet another optional embodiment, as shown in FIG. 6, the second correction current is connected in a forward direction between the second wire-in end and the second wire-out end at the second correction position when the positive inflection point appears after the second-order integration of the corresponding sinusoidal curve along the beam direction at the second correction position. Thus, the contribution of the current in the slot 1013 to the magnetic field at the pole piece 1012 close to the outermost coil is greater than the contribution to the magnetic field at the pole piece 1012 far from the outermost coil, thereby increasing the correction amount of one magnetic field integration and achieving the purpose of optimizing the integral magnetic field. Figure 5As shown, the second correction current is connected reversely between the second input terminal and the second output terminal of the second correction position, which can be implemented as follows:

[0063] The first input terminal of the second correction position is connected to the negative pole of the second power supply through the third superconducting wire and the third current lead, and the second output terminal of the second correction position is connected to the positive pole of the second power supply through the fourth superconducting wire and the fourth current lead.

[0064] In yet another optional embodiment, as shown, the second correction current is connected forwardly between the second input terminal and the second output terminal of the second correction position, which can be implemented as follows: Figure 6

[0065] The first input terminal of the second correction position is connected to the positive pole of the second power supply through the third superconducting wire and the third current lead, and the second output terminal of the second correction position is connected to the negative pole of the second power supply through the fourth superconducting wire and the fourth current lead.

[0066] It can be understood that the forward connection of the second power supply increases the current of the outermost coil of the second correction position, and the reverse connection of the second power supply reduces the current of the outermost coil of the second correction position. In addition, the present application leads the second input terminal and the second output terminal out to the cryostat through two current leads, which does not affect the normal operation of the superconducting undulator 10.

[0067] As for how much the current is increased or reduced, it can be determined by continuous debugging. For example, at the first time, the first current can be output by the second power supply, and then the magnetic field distribution of the superconducting undulator 10 is obtained. If the positive inflection point still appears in the second correction position after the second-order integral of the sinusoidal curve along the beam direction in the magnetic field distribution, the second current smaller than the first current is output by the second power supply, and then the magnetic field distribution of the superconducting undulator 10 is obtained. Continue to determine whether the current output by the second power supply needs to be adjusted according to the magnetic field distribution of the superconducting undulator 10 until the desired result is obtained.

[0068] The present application corrects the peak magnetic field and the phase error of the superconducting undulator 10, and also corrects the integral magnetic field of the superconducting undulator 10.

[0069] ​In another optional embodiment, the present application can further optimize the peak magnetic field, phase error, and integral magnetic field by filling the holes on the side of the pole piece 1012 with ferromagnetic material based on the above-mentioned correction method. The principle of this method is that the pole piece 1012 restricts the magnetic lines under the action of the coil, and when the hole positions at both ends of the pole piece 1012 are filled with a material having higher magnetic properties than the existing pole piece 1012 material, more magnetic lines will be restricted from both sides, thereby reducing the magnetic field on the axis, and vice versa. This method can correct the magnetic field at a single pole piece 1012 to a large extent, and can be used to optimize the phase error and the integral magnetic field, thereby achieving the optimization goal. In an example, the ferromagnetic material is DT4, iron-cobalt-vanadium, etc.

[0070] It can be understood that during the manufacturing process of the superconducting undulator 10, the pole piece 1012 can be provided with holes.

[0071] In a specific embodiment, the parameters of the superconducting undulator 10 are as follows: the period length is 19 mm, the length is about 1500 mm, the magnetic gap is 8.5 mm, the material of the iron core 1011 is DT4, the superconducting wire is a NbTi superconducting wire with a copper super ratio of 0.9, the peak magnetic field under 400 A is 1.07 T, there are about 10 groups of correction coils, after obtaining the magnetic field distribution without correction current, the number of groups of correction coils to be enabled and the current size are determined according to the error position, the power introduced by the 10 groups of binary current leads is about 2 W, which is within the remaining cooling capacity of the refrigerator and is safe and feasible.

[0072] The first correction method is to modify the current of the coils in the upper and lower two opposite wire slots 1013 of the first correction position of the superconducting undulator 10 as a whole, that is, the superconducting wires led out of the upper and lower two wire slots 1013 are connected in series with a pair of binary current leads, and are powered by a 10 A independent low-cost ordinary power supply. It is calculated that a 10 A ordinary power supply will not cause a quench risk of the magnet, nor will it cause damage to the power supply due to quench of the magnet coil. The correction amount is approximately linear, about 300 Gauss.

[0073] Based on the first correction method, the current of the outermost half layer coil of the second correction position is locally modified. Compared with the first scheme, the number of turns that can be operated by this method is smaller. It is calculated that a 10 A correction current can bring about an integral contribution of about 120 Gs.cm.

[0074] Finally, based on the measurement results at low temperature, the small holes on the pole piece 1012 are initially filled with DT4 small columns with the same material as the pole piece 1012. According to the test results, the length of the DT4 small column can be reduced, or iron-cobalt-vanadium can be replaced, so as to adjust the magnetic field size.

[0075] The superconducting undulator 10 magnetic field quality correction method provided by the application determines a first correction position and a second correction position that need to be corrected according to the magnetic field distribution of the superconducting undulator 10 at the current time, and reduces or increases the current at the first correction position by connecting a first correction current between the first input terminal and the first output terminal of the first correction position, locally changes the current in the slot 1013 without affecting the operation of the magnet, thereby changing the peak magnetic field of the adjacent two pole pieces 1012 at the first correction position, and the phase error of the superconducting undulator 10 can also be optimized; at the same time, the application also increases the correction amount of the integral magnetic field by connecting a second correction current between the second input terminal and the second output terminal of the second correction position, so that the current in the slot 1013 at the second correction position contributes more to the magnetic field of the pole piece 1012 close to the half-layer coil than to the magnetic field of the pole piece 1012 far from the half-layer coil, thereby increasing the correction amount of the integral magnetic field.

[0076] In another embodiment, the application also provides a superconducting undulator 10 magnetic field quality correction device 700, which comprises an acquisition module 701, a determination module 702 and a wiring module 703.

[0077] The acquisition module 701 is used to acquire the magnetic field distribution of the superconducting undulator 10 at the current time.

[0078] The determination module 702 is used to determine a first correction position and a second correction position according to the magnetic field distribution at the current time.

[0079] The wiring module 703 is used to connect a first correction current between the first input terminal and the first output terminal of the first correction position, and connect a second correction current between the second input terminal and the second output terminal of the second correction position, the first input terminal and the second output terminal are arranged according to the number of turns of the coil arranged on the first correction position, and the second input terminal and the second output terminal are arranged according to the coil arranged on the second correction position away from the outermost layer of the coil surface.

[0080] In an optional embodiment, the determination module 702 is specifically used to determine the slot 1013 corresponding to the curve part with a peak value higher or lower than the average peak value as the first correction position if the curve part with a peak value higher or lower than the average peak value exists in the sine curve.

[0081] If the curve part with a positive inflection point or a negative inflection point appears after the second-order integration of the sine curve along the beam direction, the slot 1013 corresponding to the curve part with a positive inflection point or a negative inflection point is determined as the second correction position.

[0082] In an optional embodiment, the wiring module 703 is specifically configured to connect the first input terminal of the first correction position and the negative pole of the first power supply through the first superconducting wire and the first current lead, and connect the first output terminal of the first correction position and the positive pole of the first power supply through the second superconducting wire and the second current lead, if the corresponding sinusoidal curve of the first correction position has a positive turning point after being integrated twice along the beam direction.

[0083] In an optional embodiment, the wiring module 703 is specifically configured to connect the first input terminal of the first correction position and the negative pole of the first power supply through the first superconducting wire and the first current lead, and connect the first output terminal of the first correction position and the positive pole of the first power supply through the second superconducting wire and the second current lead, if the corresponding sinusoidal curve of the first correction position has a positive turning point after being integrated twice along the beam direction.

[0084] In an optional embodiment, the wiring module 703 is specifically configured to connect the first input terminal of the first correction position and the negative pole of the first power supply through the first superconducting wire and the first current lead, and connect the first output terminal of the first correction position and the positive pole of the first power supply through the second superconducting wire and the second current lead, if the corresponding sinusoidal curve of the first correction position has a positive turning point after being integrated twice along the beam direction.

[0085] In an optional embodiment, the wiring module 703 is specifically configured to connect the first input terminal of the first correction position and the negative pole of the first power supply through the first superconducting wire and the first current lead, and connect the first output terminal of the first correction position and the positive pole of the first power supply through the second superconducting wire and the second current lead, if the corresponding sinusoidal curve of the first correction position has a positive turning point after being integrated twice along the beam direction.

[0086] In an optional embodiment, the wiring module 703 is specifically configured to connect the first input terminal of the first correction position and the negative pole of the first power supply through the first superconducting wire and the first current lead, and connect the first output terminal of the first correction position and the positive pole of the first power supply through the second superconducting wire and the second current lead, if the corresponding sinusoidal curve of the first correction position has a positive turning point after being integrated twice along the beam direction.

[0087] In an optional embodiment, the wiring module 703 is specifically configured to connect the first input terminal of the first correction position and the negative pole of the first power supply through the first superconducting wire and the first current lead, and connect the first output terminal of the first correction position and the positive pole of the first power supply through the second superconducting wire and the second current lead, if the corresponding sinusoidal curve of the first correction position has a positive turning point after being integrated twice along the beam direction.

[0088] In an optional embodiment, the wiring module 703 is specifically configured to connect the first input terminal of the first correction position and the negative pole of the first power supply through the first superconducting wire and the first current lead, and connect the first output terminal of the first correction position and the positive pole of the first power supply through the second superconducting wire and the second current lead, if the corresponding sinusoidal curve of the first correction position has a positive turning point after being integrated twice along the beam direction.

[0089] In an optional embodiment, the wiring module 703 is specifically configured to connect the first input terminal of the first correction position and the negative pole of the first power supply through the first superconducting wire and the first current lead, and connect the first output terminal of the first correction position and the positive pole of the first power supply through the second superconducting wire and the second current lead, if the corresponding sinusoidal curve of the first correction position has a positive turning point after being integrated twice along the beam direction.

[0090] In an alternative embodiment, the correction device further comprises a filling module (not shown in the figures),

[0091] a filling module for filling the openings in the side of the pole piece 1012 at the correction location with a ferromagnetic material.

[0092] It should be noted that, although the operations of the methods of the present application are described in a particular, sequential order, this order is not meant to be a limitation, and that not all operations are necessarily performed, or performed in this particular order, to achieve desirable results. In some instances, multitasking and parallel processing can be advantageous.

[0093] The above description is merely exemplary of the application and the application of the principles thereof. It is therefore intended that the scope of the application be determined solely by the claims that follow and that the application be not limited to the steps recited in the description of the preferred embodiment.

Claims

1. A method for calibrating the magnetic field quality of a superconducting undulator, characterized in that: The method comprises: Obtaining the magnetic field distribution of the superconducting undulator at a current moment; determining a first correction position and a second correction position according to the magnetic field distribution at the current moment; A first correction current is connected between a first input terminal and a first output terminal of the first correction position, and a second correction current is connected between a second input terminal and a second output terminal of the second correction position, wherein the first input terminal and the first output terminal are set according to the coils of all turns wound at the first correction position, and the second input terminal and the second output terminal are set according to the coils wound on the outermost layer away from the coil surface at the second correction position. Wherein, if the magnetic field distribution is a sine curve, determining the first correction position and the second correction position according to the magnetic field distribution at the current moment includes: If there is a curve portion in the sinusoidal curve whose peak value is higher than the average peak value or lower than the average peak value, the line groove corresponding to the curve portion whose peak value is higher than the average peak value or lower than the average peak value is determined as the first correction position; If a curve portion having a positive inflection point or a negative inflection point appears after a second-order integration of the sinusoidal curve along the beam direction, the line slot corresponding to the curve portion having the positive inflection point or the negative inflection point is determined as the second correction position.

2. The calibration method according to claim 1, wherein: Connecting a first correction current between the first input terminal and the first output terminal at the first correction position includes: If the peak value of the sinusoidal curve corresponding to the first correction position is higher than the average peak value, reversely connecting the first correction current between the first input terminal and the first output terminal of the first correction position; If the peak value of the sinusoidal curve corresponding to the first correction position is lower than the average peak value, the first correction current is connected in a forward direction between the first input terminal and the first output terminal of the first correction position.

3. The calibration method according to claim 2, wherein: The reversely connecting the first correction current between the first input terminal and the first output terminal at the first correction position includes: The first input terminal of the first correction position is connected to the negative pole of the first power supply through the first superconducting wire and the first current lead, and the first output terminal of the first correction position is connected to the positive pole of the first power supply through the second superconducting wire and the second current lead.

4. The calibration method according to claim 3, wherein: The forward connecting of the first correction current between the first input terminal and the first output terminal at the first correction position includes: The first input terminal of the first correction position is connected to the positive pole of the first power supply through the first superconducting wire and the first current lead, and the first output terminal of the first correction position is connected to the negative pole of the first power supply through the second superconducting wire and the second current lead.

5. The calibration method according to claim 1, wherein: Connecting the second correction current between the second input terminal and the second output terminal at the second correction position includes: If a positive inflection point appears after a second-order integration of the sinusoidal curve corresponding to the second correction position along the beam direction, the second correction current is reversely connected between the second input terminal and the second output terminal of the second correction position; If a negative inflection point appears after a second-order integration of the sinusoidal curve corresponding to the second correction position along the beam direction, the second correction current is positively connected between the second input terminal and the second output terminal of the second correction position.

6. The calibration method according to claim 5, characterized in that: The reversely connecting the second correction current between the second input terminal and the second output terminal at the second correction position includes: The second input terminal of the second correction position is connected to the negative pole of the second power supply through the third superconducting wire and the third current lead, and the second output terminal of the second correction position is connected to the positive pole of the second power supply through the fourth superconducting wire and the fourth current lead.

7. The calibration method according to claim 5, characterized in that: The forward connection of the second correction current between the second input terminal and the second output terminal at the second correction position includes: The second input terminal of the second correction position is connected to the positive pole of the second power supply through the third superconducting wire and the third current lead, and the second output terminal of the second correction position is connected to the negative pole of the second power supply through the fourth superconducting wire and the fourth current lead.

8. The calibration method according to claim 1, wherein: The method further comprises: The opening on the side of the pole piece at the correction position is filled with ferromagnetic material.

9. A device for correcting the magnetic field quality of a superconducting undulator, characterized in that: The device comprises: An acquisition module, configured to acquire the magnetic field distribution of the superconducting undulator at a current moment; a determination module, configured to determine a first correction position and a second correction position according to the magnetic field distribution at the current moment; a wiring module, configured to connect a first correction current between a first input terminal and a first output terminal of the first correction position, and connect a second correction current between a second input terminal and a second output terminal of the second correction position, wherein the first input terminal and the second output terminal are arranged based on the coil having all turns wound at the first correction position, and the second input terminal and the second output terminal are arranged based on the coil wound on the outermost layer away from the coil surface at the second correction position; If the magnetic field distribution is a sine curve, the determining module is specifically configured to, if there is a curve portion in the sine curve with a peak value higher than an average peak value or lower than an average peak value, determine the wire slot corresponding to the curve portion with a peak value higher than an average peak value or lower than the average peak value as the first correction position; If a curve portion having a positive inflection point or a negative inflection point appears after a second-order integration of the sinusoidal curve along the beam direction, the line slot corresponding to the curve portion having the positive inflection point or the negative inflection point is determined as the second correction position.

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