Superconducting and permalloy mixed shielding neutron regulation and control method and device

Abstract

The invention discloses a superconducting and permalloy mixed shielding neutron regulation and control method and device, and relates to the technical field of neutron polarization. The method comprises the following steps: S1, vacuumizing a vacuum cavity; S2, building a permalloy cover; S3, cooling a low-temperature copper chain and superconducting tape complex; S4, dismounting the permalloy cover; the problem that in the prior art, the superconducting state is unstable due to the fact that the temperature is easily interfered by an external magnetic field in the process of cooling to the superconducting critical temperature is solved, neutron regulation and control are achieved on the experimental technology and device through current change of a superconducting strip spiral coil magnetic field in the vacuum cavity and change of an external rotating magnetic field, and the experimental efficiency is improved. Stable operation of 10A current of the superconducting strip spiral coil is achieved, and the external spiral magnetic field can be adjusted at any angle of 0.1 degree in the 360-degree direction.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of neutron polarization, in particular to a method and device for regulating neutrons by using a superconductor and permalloy mixed shielding. BACKGROUND

[0002] As a classic soft magnetic material, permalloy is applied to electromagnetic shielding due to the exploration demand for high magnetic permeability materials in the early 20th century. Superconducting materials need electromagnetic shielding during the cooling process for the following reasons:

[0003] (1) Avoiding the magnetic flux pinning effect caused by the penetration of the magnetic field. When the superconducting material is cooled below the critical temperature (Tc) in an external magnetic field environment, the magnetic field will penetrate the superconductor in the form of quantized magnetic flux lines. These "frozen" magnetic flux lines will form pinning centers, significantly reducing the transmission capacity (critical current density Jc) of the superconducting current, and even causing irreversible performance degradation. Electromagnetic shielding can ensure that the superconductor enters the superconducting state in the zero-field cooling (ZFC) state, avoiding magnetic flux trapping.

[0004] (2) Avoiding the occurrence of eddy current heat effect to destroy the superconducting state. The changing magnetic field will induce eddy currents in the superconductor, and the resistance effect in the normal state will generate Joule heat. Near the critical temperature, this thermal disturbance may hinder the superconducting phase transition, and even cause local thermal runaway. For example, when NbTi alloy is cooled at 4.2K, an alternating current magnetic field of only 1 muT can cause a temperature rise of 10 mK.

[0005] (3) Maintaining macroscopic quantum coherence. The macroscopic quantum effect (such as Josephson effect) of the superconducting state is extremely sensitive to the external magnetic field. Experiments have shown that the quantum interference device (SQUID) of high-temperature superconductor YBCO will exhibit observable phase disturbance under a magnetic field of 10^-12T. Electromagnetic shielding can protect the phase consistency of the superconducting wave function.

[0006] (4) Inhibiting the risk of quench propagation. In the superconducting magnet system, the transient electromagnetic field generated by local quench may trigger a chain reaction through electromagnetic induction. The composite shielding structure composed of multi-layer permalloy (mu r>10^5) and high-conductivity oxygen-free copper (sigma=5.8x10^7S / m) can attenuate the transient magnetic field by more than 60dB, which can gain critical milliseconds of response time for the active protection system.

[0007] (5) Meeting the demand of precision measurement. The decoherence time T2 of superconducting qubits (such as Transmon) is extremely sensitive to magnetic field fluctuations, and a magnetic field fluctuation of 1 muT may cause T2 to shorten by an order of magnitude. Using a mu-metal shielding cylinder combined with an active compensation coil can control the residual magnetic field to the level of 10^-9T.

[0008] The prior art is susceptible to external magnetic field interference during cooling to the superconducting critical temperature, resulting in instability of the superconducting state, and therefore, a device is needed to shield the external magnetic field to ensure that the superconducting material is in a weak magnetic field or even zero magnetic field environment during the cooling process.

[0009] Superconducting material is a material that exhibits zero resistance and complete magnetic flux exclusion at a specific temperature. In the superconducting state, it can transmit current without energy loss and repel magnetic fields. Superconducting materials have important applications in many fields, including magnetic resonance imaging, particle accelerators, and magnetic levitation technology. Superconducting is a highly efficient means of generating magnetic fields, making it ideal for generating and controlling magnetic fields to confine neutrons. Superconducting materials have been an active research area both domestically and internationally. Many international research institutions and universities have conducted extensive research on superconducting materials, making important contributions to the basic research and application of superconducting materials. This includes the discovery of new superconducting materials, the study of superconducting mechanisms, and the improvement of superconducting critical temperatures. In China, research institutions and universities such as the Chinese Academy of Sciences, Tsinghua University, and the University of Science and Technology of China have also conducted extensive research on superconducting materials. Chinese scientists have made important progress in high-temperature superconductors and iron-based superconductors, continuously driving the development of the superconducting materials field. At the same time, China has large-scale superconducting material research facilities (such as the National Superconducting Laboratory) that provide important support and platforms for superconducting material research.

[0010] Neutron polarization is an important target of neutron control. Polarized neutrons refer to neutrons whose spin direction is aligned with their motion direction. This alignment can be achieved by passing neutrons through a magnetic field or using special devices. Polarized neutrons have important application value in the fields of magnetic materials, biological structures and condensed matter physics, and can provide information about the magnetic and structural properties of materials. By using polarized neutrons for scattering experiments, scientists can gain a deeper understanding of the microscopic structure and magnetic behavior of materials. Polarized neutron scattering is the only scattering technique that can distinguish between magnetic scattering and nuclear scattering. Polarized neutron technology is widely used in existing neutron sources, and occupies more than half of the spectrum line. Many international neutron scattering laboratories, such as the Institut Laue-Langevin (ILL) in Europe and the National Institute of Standards and Technology (NIST) in the United States, have polarized neutron research projects. In China, the Chinese Academy of Sciences' large scientific device, the China Spallation Neutron Source (CSNS), also has polarized neutron research facilities. These research work involves material science, physics, biology and other fields, and has important significance for studying the magnetism, structure and dynamics of materials. The development of superconducting constrained neutron control method research helps to improve the stability of neutron confinement, especially the polarization intensity and stability of neutrons. By studying the confinement effect in superconducting materials through neutron scattering technology, detailed information about the structure, magnetism and dynamics of superconducting materials can be obtained, which helps to discover new superconducting materials. At the same time, the successful implementation of the project will provide new ideas and new devices for the problems of polarized neutron technology, and promote the application of polarized neutron technology in neutron sources. The current superconducting technology is difficult to modulate the magnetic field to a specific state through self-control, and it is extremely difficult to accurately control the angle of the magnetic field direction. How to realize the controllable magnetic field that can be modulated and the accurate control of the angle of the magnetic field direction of the superconducting tape spiral coil during stable operation has become a problem to be solved. SUMMARY

[0011] (I) Technical problems solved

[0012] The present application solves the problem that the existing technology is easily disturbed by external magnetic field during cooling to superconducting critical temperature, resulting in unstable superconducting state. It provides a superconducting and permalloy mixed shielding neutron control method and device for realizing the accurate control of the angle of the magnetic field direction of the controllable magnetic field that can be modulated and the superconducting tape spiral coil during stable operation.

[0013] (II) Technical solutions

[0014] The neutron control method and device of the application rely on the complete diamagnetism (Meissner effect) of the first / second superconductor to establish a strictly defined magnetic field confinement surface, thereby achieving precise control of neutron spin polarization through controlled Larmor precession, specifically a neutron control method using superconducting and permalloy hybrid shielding, comprising the following steps:

[0015] S1, vacuuming the vacuum chamber: two vacuum chambers are simultaneously vacuumed by two sets of vacuum pumps to a vacuum degree of less than 0.0001 Pa;

[0016] S2, building permalloy covers: two permalloy covers are built at the same time, after being inserted into the lower front plate and the lower rear plate, the front plate, the left plate, the right plate, and the rear plate are respectively spliced, and finally the upper front plate and the upper rear plate are spliced, the side edges are fixed with bolts to ensure that there is no magnetic leakage due to gaps;

[0017] S3, cooling process of the low-temperature copper chain and the superconducting tape complex: open the cryogenic pump, the cryogenic pump transports 40K cryogenic medium to the cryogenic cold head, which can ensure that the superconducting tape and superconducting sheet in the complex are cooled to below 77K;

[0018] S4, removing the permalloy cover: remove the permalloy cover from the six directions respectively;

[0019] S5, installing the vacuum chamber: install the vacuum chamber on the neutron beam line of the neutron spectrometer, fix the vacuum chamber after aligning the neutron beam and the center of the superconducting sheet, and install and fix the zero-magnetic chamber and the rotating magnetic field;

[0020] S6, superconducting tape spiral coil energization to verify superconductivity: energize the superconducting tape spiral coil, and then gradually increase the current intensity from 1A;

[0021] S7, passing the neutron beam: after personnel evacuation, open the neutron beam shutter to let the neutrons pass through the entire device, and detect the neutrons at the outlet end of the device;

[0022] S8, modulating the superconducting magnetic field and controlling the rotating magnetic field to achieve neutron control: after the neutron beam line stabilizes the output, the specific superconducting magnetic field can be adjusted by changing the superconducting tape spiral coil, and the angle of the rotating magnetic field can also be changed to achieve neutron control.

[0023] Specifically, in step S6, the performance test of the superconducting tape spiral coil uses the energization method to verify its zero resistance characteristic.

[0024] Specifically, the voltage change of the superconducting tape helical coil needs to be monitored in real time during the step S6 test process. According to the basic characteristics of superconductors, when the material is in a superconducting state, its resistance will completely disappear. Therefore, if the voltage reading remains unchanged (i.e., the voltage does not increase with the increase of the current) under the condition of continuously increasing current, it can be determined that the tape is indeed in a superconducting state. The theoretical basis of this test method is Ohm's law (U = IR). In the superconducting state, since R = 0, the voltage U should be zero regardless of the change of the current I. The technical device realizes the stable operation of the superconducting state of the current 4A.

[0025] A preferred superconducting and permalloy mixed shielding neutron regulating device, the device comprises a low temperature cold head mounted on a base, a vacuum cavity, a permalloy shielding cover and a rotatable weak magnetic field polarized neutron scattering sample device-zero magnetic cavity, the low temperature cold head is communicated with the cold head connecting flange cylinder assembled on the vacuum cavity through a strong electric aviation connector, the vacuum cavity is located inside the permalloy shielding cover and is installed with a rotating magnetic field on one side thereof; a neutron channel and an adjusting rack are also mounted on the base, and the vacuum cavity and the permalloy shielding cover are both mounted on the neutron channel and the adjusting rack.

[0026] Preferably, a low-temperature copper chain and a superconducting tape magnetic field complex are fixed on the strong electric aviation connector inside the vacuum cavity, and a superconducting tape magnetic field with a permalloy ring and a superconducting tape adjustable tension flying wire block is provided.

[0027] Preferably, a vacuum pump connector in communication with the YBCO superconducting tape power supply interface is fixed above the vacuum cavity.

[0028] Preferably, the low-temperature copper chain and superconducting tape magnetic field complex comprises a low-temperature cold head connecting plate connected with the cold head connecting flange cylinder through a strong electric aviation connector, a copper chain vertical plate connected with the low-temperature cold head connecting plate through a positioning adjusting block, and a superconducting assembly installed at the end of the copper chain vertical plate, and a weak electric aviation connector is installed on one side of the positioning adjusting block.

[0029] Preferably, the low-temperature copper chain and superconducting tape magnetic field complex further comprises a direct current positive and negative electrode connector fixedly installed on one side of the copper chain vertical plate through a Niron bolt and an aluminum nitride ceramic sheet.

[0030] Preferably, the superconducting assembly comprises a superconducting sheet, a superconducting tape helical coil and a sensor, each of which is installed on the front and back sides, and the sensor comprises a superconducting tape helical coil sensor and a superconducting sheet temperature sensor.

[0031] The upper front plate and the upper rear plate of the preferred permalloy shield form an upper plate, and a joint hole is formed in the upper plate to allow a vacuum pump joint and a cold head connecting flange barrel to pass through; the lower front plate and the lower rear plate of the permalloy shield form a lower plate; and an aviation joint hole is formed in the left plate of the permalloy shield, and the aviation joint hole is used for passing through a weak current aviation joint.

[0032] (III) Beneficial Effects

[0033] The present application shields external magnetic field by the external permalloy shield, ensures that the superconducting tape and the superconducting sheet are not interfered by the external magnetic field during the process of being cooled to the superconducting critical temperature, so that the stable superconducting state is obtained; the superconducting tape spiral coil modulates the controllable magnetic field after being electrified, and is shielded and trimmed by the superconducting sheet which is transparent to neutrons and has no current, and finally forms a specific form of magnetic field; the neutron regulation is realized in the experimental technology and the device through the current change of the magnetic field of the superconducting tape spiral coil in the vacuum cavity and the change of the external rotating magnetic field. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a method step flow chart of the present application;

[0035] Figure 2 It is a general assembly schematic diagram of the present application;

[0036] Figure 3 It is a vacuum cavity assembly schematic diagram of the present application;

[0037] Figure 4 It is a permalloy shield assembly schematic diagram of the present application;

[0038] Figure 5 It is a low-temperature copper chain and superconducting tape magnetic field complex schematic diagram of the present application.

[0039] In the figure: 1, low-temperature cold head; 2, vacuum cavity; 3, permalloy shield; 4, zero-magnetic cavity; 5, rotating magnetic field; 6, neutron channel and adjusting frame; 7, base; 8, cold head connecting flange cylinder; 9, vacuum pump joint; 10, YBCO superconducting tape power supply interface; 11, strong electric aviation joint; 21, weak electric aviation joint; 22, low-temperature copper chain and superconducting tape magnetic field complex; 23, superconducting tape adjustable tension flying wire block; 24, permalloy ring; 25, superconducting tape magnetic field; 26, superconducting sheet; 31, upper front plate; 32, upper rear plate; 33, front plate; 34, rear plate; 35, left plate; 36, right plate; 37, left plate aviation joint hole; 38, lower front plate; 39, lower rear plate; 221, low-temperature cold head connecting plate; 222, positioning and adjusting block; 223, DC positive and negative electrode joint; 224, copper chain vertical plate; 225, invar bolt; 226, aluminum nitride ceramic sheet; 227, superconducting sheet; 228, superconducting sheet temperature sensor; 229, superconducting tape spiral coil sensor; 220, superconducting tape spiral coil. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0041] As shown in the figure, the present application provides a kind of neutron regulation method of superconducting and permalloy mixed shielding, comprising the following steps: Figures 1-5 S1, vacuum cavity is pumped: two vacuum cavities 2 are pumped by two sets of vacuum pumps simultaneously, and the vacuum degree is less than 0.0001Pa;

[0042] S2, build permalloy cover: while building two permalloy shields 3, after inserting lower front plate 38 and lower front plate 39, respectively, into front plate 33, left plate 35, right plate 36 and rear plate 34, finally into upper front plate 31 and upper rear plate 32, side is fixed with bolt, ensure that there is no magnetic leakage due to gap in the splicing place;

[0043] S3, the cooling process of low-temperature copper chain and superconducting tape complex: open low-temperature pump, low-temperature pump transports 40K low-temperature medium to low-temperature cold head 1, to ensure that the superconducting tape and superconducting sheet 26 in the complex are cooled to below 77K;

[0044] S4, remove permalloy cover: remove permalloy shield 3 from six directions respectively;

[0045]

[0046] ​S5, installing the vacuum cavity 2: install the vacuum cavity 2 on the neutron beam line of the neutron spectrometer, fix the vacuum cavity 2 after aligning the neutron beam and the center of the superconducting sheet 26, and install and fix the zero magnetic cavity 4 and the rotating magnetic field 5;

[0047] S6, superconducting tape spiral coil 220 is powered to verify superconductivity: the performance test of the superconducting tape spiral coil 220 uses the power-on method to verify its zero resistance characteristic, the superconducting tape spiral coil 220 is powered on, and then the current intensity is gradually increased from 1A; real-time monitoring of the voltage change of the superconducting tape spiral coil 220 is required during the test process, according to the basic characteristics of superconductors, when the material is in a superconducting state, its resistance will completely disappear, therefore, if the voltage table reading remains unchanged (i.e. the voltage does not increase with the increase of the current) under the condition of continuously increasing current, it can be determined that the tape is indeed in a superconducting state; the theoretical basis of this test method is Ohm's law (U = IR), in the superconducting state, because R = 0, therefore, no matter how the current I changes, the voltage U should be zero; the technical device realizes the superconducting state of the stable operation of the current 4A;

[0048] S7, pass the neutron beam: after the personnel are evacuated, open the neutron beam shutter to let the neutrons pass through the entire device, and detect the neutrons at the outlet end of the device;

[0049] S8, modulate the superconducting magnetic field and control the rotating magnetic field 5 to realize neutron regulation: after the neutron beam line is stabilized, the specific superconducting magnetic field is adjusted by changing the superconducting tape spiral coil 220, and the angle of the rotating magnetic field 5 can also be changed to realize neutron regulation.

[0050] The application provides a neutron regulating device with superconducting and permalloy mixed shielding, which comprises a low-temperature cold head 1, a vacuum cavity 2, a permalloy shielding cover 3 and a rotatable weak magnetic field polarized neutron scattering sample device, i.e. a zero magnetic cavity 4, which are installed on a base 7; the low-temperature cold head 1 is communicated with a cold head connecting flange barrel 8 which is assembled on the vacuum cavity 2 through a strong electric aviation connector 11; the vacuum cavity 2 is located inside the permalloy shielding cover 3 and is installed with a rotating magnetic field 5 on one side of the permalloy shielding cover 3; the vacuum cavity 2 is internally installed with a low-temperature copper chain and superconducting tape magnetic field 25 complex 22 which is fixed on the strong electric aviation connector 11 and a superconducting tape magnetic field 25 which is provided with a permalloy ring 24 and a superconducting tape adjustable tight flying wire block 23; the low-temperature copper chain and superconducting tape magnetic field complex 22 comprises a low-temperature cold head connecting plate 221 which is connected with the cold head connecting flange barrel 8 through the strong electric aviation connector 11, a copper chain vertical plate 224 which is connected with the low-temperature cold head connecting plate 221 through a positioning adjusting block 222 and a superconducting assembly which is installed at the end of the copper chain vertical plate 224; the positioning adjusting block 222 is installed with a weak electric aviation connector 21 on one side; the superconducting assembly comprises a front and back superconducting sheet 26, a superconducting tape spiral coil 220 and a sensor; the sensor comprises a superconducting tape spiral coil sensor 229 and a superconducting sheet temperature sensor 228; the low-temperature copper chain and superconducting tape magnetic field complex 22 further comprises a direct current positive and negative electrode connector 223 which is fixedly installed on one side of the copper chain vertical plate 224 through a ni-non bolt 225 and an aluminum nitride ceramic sheet 226; a vacuum pump connector 9 which is communicated with a YBCO superconducting tape power supply interface 10 is fixedly installed above the vacuum cavity 2; a joint hole which is communicated with the vacuum pump connector 9 and the cold head connecting flange barrel 8 is formed in an upper plate which is composed of an upper front plate 31 and an upper rear plate 32 of the permalloy shielding cover 3; a lower plate which is composed of a lower front plate 38 and a lower rear plate 39 of the permalloy shielding cover 3; a left plate aviation connector hole 37 which is communicated with the weak electric aviation connector 21 is formed in a left plate 35 of the permalloy shielding cover 3; a neutron channel and adjusting frame 6 is further installed on the base 7; the vacuum cavity 2 and the permalloy shielding cover 3 are both installed on the neutron channel and adjusting frame 6.

[0051] The working principle of the superconducting and permalloy mixed shielding neutron regulating method and device is as follows:

[0052] The function of the permalloy cover is that the superconducting sheet 26 and superconducting wire are easily interfered by external electromagnetic field during the process of being cooled to the superconducting critical temperature, so that the superconducting efficiency is lost, therefore, the permalloy shielding cover 3 is needed to shield the whole superconducting cooling space during the cooling process; the necessity of the permalloy shielding cover 3 being made to be detachable is that the vacuum low-temperature superconducting device needs to be installed near other devices after being cooled to the critical temperature, so that the permalloy shielding cover 3 interferes with other devices, therefore, the permalloy shielding cover 3 needs to be removed, the permalloy shielding cover 3 is like Figure 4As shown, the six panel surfaces can be removed from the front, back, top and bottom, respectively; the superconducting tape forms a spiral coil to form a controllable magnetic field: in the required place (mainly control the number of coils, current value, voltage value), for regulating the neutron beam; the role of superconducting sheet 26: in the direction of the neutron beam, a magnetic field with quantifiable width is needed, but the electromagnetic field formed by the superconducting tape is a radial magnetic field, adding the superconducting sheet 26 can limit the magnetic field to a fixed width magnetic field. At the same time, the superconducting sheet 26 is open to the neutron beam at the superconducting critical temperature.

[0053] Below the superconducting critical temperature Tc, superconductors exhibit complete diamagnetism (Meissner effect) and zero resistance characteristics, making them have unique advantages in the field of electromagnetic field shielding and limiting. The basic principles of superconducting electromagnetic shielding mainly include: Meissner effect: superconductors below Tc will repel external magnetic fields, and the magnetic field lines are limited to the surface of the superconductor, and the internal magnetic flux density is zero. This effect is the basis for static magnetic field shielding; surface current shielding: the surface of the superconductor induces a shielding current (non-dissipative), which cancels out the external magnetic field, suitable for low frequency and static magnetic field; vortex state limitation: type II superconductors allow magnetic flux vortices to enter when the magnetic field is higher than the lower critical magnetic field, but the magnetic field distribution can be limited by pinning effect.

[0054] Embodiment:

[0055] As Figures 1-5As shown, two vacuum cavities 2 are simultaneously evacuated by two sets of vacuum pumps to a vacuum degree of 0.00005 Pa, and after the vacuumization is completed, two permalloy shielding covers 3 are simultaneously built, and after the lower front plate 38 and the lower rear plate 39 are inserted, the front plate 33, the left plate 35, the right plate 36, and the rear plate 34 are respectively spliced, and finally the upper front plate 31 and the upper rear plate 32 are spliced, and the side edges are fixed by bolts to ensure that there is no magnetic leakage due to gaps. Turn on the cryogenic pump, and the cryogenic pump delivers 40K low-temperature medium to the cryogenic cold head 1 to ensure that the superconducting tape and the superconducting sheet 26 in the superconducting copper chain and superconducting tape complex are cooled to below 77K. After waiting for the temperature to stabilize, check whether all indicators of the device are normal, and under the condition of ensuring safety, the permalloy shielding cover 3 is removed from six directions. Then, the vacuum cavity 2 is installed on the neutron beam line of the neutron spectrometer, aligned with the neutron beam and the center of the superconducting sheet 26, and then the vacuum cavity 2 is fixed, and the zero magnetic cavity 4 and the rotating magnetic field 5 are installed and fixed. Next, the superconducting tape spiral coil 220 is powered to verify the superconductivity, and the performance test of the superconducting tape spiral coil 220 usually uses the power-on method to verify its zero-resistance characteristic. First, the superconducting tape spiral coil 220 is powered on, and then the current intensity is gradually increased from 1A. The voltage change of the superconducting tape spiral coil 220 needs to be monitored in real time during the test. According to the basic characteristics of superconductors, when the material is in a superconducting state, its resistance will completely disappear. Therefore, if the voltage reading remains unchanged (i.e., the voltage does not increase with the increase of the current) under the condition of continuously increasing current, it can be determined that the tape is indeed in a superconducting state. The theoretical basis of this test method is Ohm's law (U=IR), and in the superconducting state, R=0, so no matter how the current I changes, the voltage U should be zero. The technical device realizes the stable operation of the superconducting state of the current 4A. After the personnel are evacuated, the neutron beam gate is opened to let the neutrons pass through the entire device, and the neutrons are detected at the outlet end of the device; after the neutron beam line is stabilized, the specific superconducting magnetic field is adjusted by changing the superconducting tape spiral coil 220, and the angle of the rotating magnetic field 5 can also be changed to achieve neutron control. The technical device realizes the stable operation of the superconducting tape spiral coil 220 10A current, and the external spiral magnetic field is adjusted at 0.1° step angle in any direction.

Claims

1. A neutron modulation method using a hybrid shielding of superconductivity and permalloy, characterized in that: Includes the following steps: S1. Vacuuming of the vacuum chambers: The two vacuum chambers are simultaneously evacuated by two sets of vacuum pumps until the vacuum level is less than 0.0001 Pa. S2. Constructing the permalloy cover: Construct two permalloy covers at the same time. After inserting the lower front plate and the lower rear plate, assemble the front plate, left plate, right plate, and rear plate respectively. Finally, assemble the upper front plate and the upper rear plate. Fix the sides with bolts to ensure that there is no magnetic leakage due to gaps at the joint. S3, Cooling process of the low-temperature copper chain and superconducting tape complex: Turn on the low-temperature pump and deliver a 40K low-temperature medium to the low-temperature cold head to ensure that the superconducting tape and superconducting sheet in the complex are cooled to below 77K. S4. Remove the permalloy cover: Remove the permalloy cover from six directions respectively; S5. Install the vacuum chamber: Install the vacuum chamber onto the neutron beam line of the neutron spectrometer, align the vacuum chamber with the center of the neutron beam and the superconducting sheet, and then fix the vacuum chamber, and install and fix the zero magnetic chamber and the rotating magnetic field. S6. Verify superconductivity by energizing the superconducting tape spiral coil: Energize the superconducting tape spiral coil and gradually increase the current intensity starting from 1A; S7. Neutron Beam Passage: After personnel evacuation, open the neutron beam gate to allow neutrons to pass through the entire device, and detect neutrons at the device's exit end; S8. Neutron modulation by modulating superconducting magnetic fields and controlling rotating magnetic fields: After the neutron beamline is stably output, the angle of the rotating magnetic field can also be changed by adjusting the specific superconducting magnetic field by changing the spiral coil of the superconducting tape, thus achieving neutron modulation.

2. The neutron modulation method using a hybrid shielding of superconducting and permalloy alloy according to claim 1, characterized in that: In step S6, the performance test of the superconducting tape spiral coil is performed by using the energizing method to verify its zero-resistance characteristics.

3. The neutron modulation method of superconducting and permalloy hybrid shielding according to claim 1, characterized in that: During the test in step S6, it is necessary to monitor the voltage change of the superconducting tape spiral coil in real time. According to the basic characteristics of superconductors, when the material is in the superconducting state, its resistance will completely disappear. Therefore, if the voltmeter reading remains unchanged when the current continues to increase, it can be determined that the tape is indeed in the superconducting state.

4. A neutron modulation device with hybrid shielding of superconductivity and permalloy, characterized in that: The device includes a cryogenic cold head, a vacuum chamber, a permalloy shield, and a rotatable weak magnetic field polarized neutron scattering sample device—a zero magnetic chamber—mounted on a base. The cryogenic cold head is connected to a cold head connecting flange mounted on the vacuum chamber via a high-voltage aviation connector. The vacuum chamber is located inside the permalloy shield and has a rotating magnetic field installed on one side of it. A neutron channel and an adjustment frame are also mounted on the base, and the vacuum chamber and the permalloy shield are both mounted on the neutron channel and the adjustment frame.

5. The neutron modulation device with superconducting and permalloy hybrid shielding according to claim 4, characterized in that: The vacuum chamber contains a low-temperature copper chain and a superconducting tape magnetic field complex fixed to a high-voltage aviation connector, as well as a superconducting tape magnetic field with a permalloy ring and an adjustable tension flying wire block.

6. The neutron modulation device with superconducting and permalloy hybrid shielding according to claim 4, characterized in that: A vacuum pump connector, which is connected to the power interface of the YBCO superconducting tape, is fixed above the vacuum chamber.

7. A neutron modulation device with superconducting and permalloy hybrid shielding according to claim 5, characterized in that: The low-temperature copper chain and superconducting tape magnetic field complex includes a low-temperature cold head connecting plate connected to the cold head connecting flange via a high-voltage aviation connector, a copper chain vertical plate connected to the low-temperature cold head connecting plate via a positioning adjustment block, and a superconducting component installed at the end of the copper chain vertical plate. A low-voltage aviation connector is installed on one side of the positioning adjustment block.

8. A neutron modulation device with superconducting and permalloy hybrid shielding according to claim 5, characterized in that: The low-temperature copper chain and superconducting tape magnetic field complex also includes DC positive and negative terminals that are fixedly installed on one side of the copper chain vertical plate by Ninon bolts and aluminum nitride ceramic sheets.

9. A neutron modulation device with superconducting and permalloy hybrid shielding according to claim 7, characterized in that: The superconducting assembly includes a superconducting sheet mounted at the front and back, a superconducting tape spiral coil, and a sensor. The sensor includes a superconducting tape spiral coil sensor and a superconducting sheet temperature sensor.

10. A neutron modulation device with superconducting and permalloy hybrid shielding according to claim 4, characterized in that: The upper plate, consisting of the upper front plate and the upper rear plate of the permalloy shield, has a joint hole that allows the vacuum pump connector and the cold head connecting flange to pass through. The lower plate, consisting of the lower front plate and the lower rear plate of the permalloy shield, has an aviation joint hole on the left plate, which allows the low-voltage aviation connector to pass through.

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