Neutron polarization reversal device and reversal device

Abstract

A neutron polarization reversal device includes: a guide magnet for generating a guide magnetic field within a preset area; a reversal assembly including a reversal bracket, a first coil, and a second coil, wherein the first coil and the second coil are wound around the reversal bracket so as to be positioned within the preset area; a driving device for outputting a current to the first coil after receiving a target shooting control signal from an accelerator, so as to generate a compensation magnetic field opposite to the guide magnetic field, and to form a demagnetizing field region in the intersecting area of ​​the guide magnetic field and the compensation magnetic field; and further for outputting a current to the second coil, so as to generate a precession magnetic field orthogonal to the guide magnetic field and the compensation magnetic field in the demagnetizing field region. Neutron polarization reversal is achieved based on the Larmor precession of neutrons, making the neutron polarization reversal device simple in structure, easy to implement, and fast in reversal speed. Furthermore, the device can receive a target shooting control signal from an accelerator and perform neutron reversal in accordance with the target shooting control signal. The present invention also provides a neutron polarization reversal device.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron polarization reversal, and in particular to a neutron polarization reversal device and a reversal device. Background Art

[0002] Neutrons, characterized by their lack of charge, magnetic moment, and strong penetrating properties, can distinguish light elements, isotopes, and neighboring elements, making them a powerful tool for exploring the microstructure of matter. Polarized neutrons will further leverage these advantages, finding widespread application in fields such as condensed matter physics and chemistry, nanomaterials, protein and biology, and industrial nondestructive depth testing. In polarized neutron experiments, the polarization of the neutrons must be flipped to measure the contribution of different polarization states to the total beam current, a necessary operation for calculating the neutron polarizability.

[0003] The device that achieves neutron polarization reversal is called a polarization flipper, which is used to change the relative angle between the neutron's spin and its guiding magnetic field. Based on different implementation principles, polarization flippers include π polarization flippers, RF polarization flippers, and other types. However, the implementation of these polarization flippers is relatively complex and the reversal speed is slow. For example, in a common polarization flipper, a vacuum thermostat is used to provide a vacuum and low-temperature environment for the superconducting anti-magnetic component, so that the superconducting anti-magnetic component forms a layer of Meissner anti-magnetic layer within the vacuum thermostat. Then, two guiding magnetic fields with opposite magnetic field directions are formed on both sides of the Meissner anti-magnetic layer. The guiding magnetic fields are used to guide the polarization of neutrons passing through the guiding magnetic fields and cause the polarization of neutrons after passing through the Meissner anti-magnetic layer to be reversed. Because the polarization flipper needs to provide a vacuum and low-temperature environment for the superconducting anti-magnetic component, its implementation is complex, the implementation cost is high, and the reversal speed is slow. Summary of the Invention

[0004] The main technical problem solved by the present invention is that the polarization flipper is complex to implement, has high implementation cost and slow flipping speed.

[0005] According to the first aspect, an embodiment provides a neutron polarization reversal device, comprising:

[0006] A guide magnet, used to generate a guide magnetic field in a preset area;

[0007] The flip assembly includes a flip bracket, a first coil and a second coil, wherein the first coil and the second coil are wound around the flip bracket to be arranged in the preset area.

[0008] The driving device is used to output current to the first coil to generate a compensation magnetic field opposite to the guide magnetic field, and to form a demagnetizing field region in the intersecting area between the guide magnetic field and the compensation magnetic field. The driving device is also used to output current to the second coil to generate a precession magnetic field orthogonal to the guide magnetic field and the compensation magnetic field in the demagnetizing field region, and the precession magnetic field is used to perform polarization reversal on neutrons entering therein.

[0009] According to the second aspect, an embodiment provides a neutron polarization flipper, comprising:

[0010] A guide magnet, used to generate a guide magnetic field in a preset area;

[0011] A flip assembly, comprising a flip bracket, a first coil and a second coil;

[0012] The first coil and the second coil are wound on the flip bracket to be arranged in the preset area. The first coil is used to generate a compensation magnetic field opposite to the guide magnetic field after being energized, so that the guide magnetic field and the compensation magnetic field form a demagnetizing field area in the intersecting area. The second coil is used to generate a precession magnetic field orthogonal to the guide magnetic field and the compensation magnetic field in the demagnetizing field area after being energized. The precession magnetic field is used to perform polarization flipping on neutrons entering therein.

[0013] In some embodiments, the guide magnets include a first set of magnets and a second set of magnets;

[0014] The first and second groups of magnets are arranged oppositely on both sides of the preset area, and are placed in parallel with each other, so that the guiding magnetic field generated between the first and second groups of magnets in the preset area is a uniform magnetic field.

[0015] In some embodiments, the guide magnet further includes a first set of magnet supports and a second set of magnet supports;

[0016] The first group of magnets and the second group of magnets each include a plurality of magnets, and the first group of magnet brackets and the second group of magnet brackets are both provided with a plurality of mounting slots matching the magnets, and the plurality of magnets are respectively arranged in the mounting slots of the first group of magnet brackets and the second group of magnet brackets to form the first group of magnets and the second group of magnets, respectively.

[0017] In some embodiments, the flip bracket includes two horizontal winding columns parallel to each other, and two vertical winding columns respectively perpendicular to the horizontal winding columns;

[0018] The first coil is wound on two horizontal winding poles in a direction perpendicular to the horizontal winding poles, and the second coil is wound on two vertical winding poles in a direction orthogonal to the vertical winding poles. The two vertical winding poles are respectively arranged parallel to the first group of magnets and the second group of magnets.

[0019] In some embodiments, the two horizontal winding columns or the two vertical winding columns are extended to form a mounting block exposed from the flip bracket, and the mounting block is used for mounting and fixing the flip bracket.

[0020] In some embodiments, the current output by the driving device received by the second coil when performing a polarization flip on a neutron varies to generate the precession magnetic field with varying magnetic field strength, and the rate of change of the strength of the precession magnetic field is less than a preset value.

[0021] In some embodiments, the magnetic field strength of the precessing magnetic field changes from an initial magnetic field strength to a preset magnetic field strength, and then changes from the preset magnetic field strength to the initial magnetic field strength.

[0022] In some embodiments, the second coil is configured to receive a current output by a driving device when neutrons are emitted toward the precession magnetic field, so as to generate the precession magnetic field.

[0023] In some embodiments, two support plates and four mounting brackets are further included, wherein one end of two of the mounting brackets clamps one end of one of the support plates, and the other ends of two of the mounting brackets clamp one end of the other support plate, and one end of another two of the mounting brackets clamps the other end of one of the support plates, and the other ends of another two of the mounting brackets clamp the other end of the other support plate, the guide magnet is fixed between the two support plates, and the flip bracket is fixed on at least one of the mounting brackets.

[0024] According to the above-described embodiment, a neutron polarization flipper and neutron polarization flipping device generate a guide magnetic field within a predetermined region using a guide magnet. A flipping assembly then generates a compensating magnetic field, in the opposite direction of the guide magnetic field, via a first coil, on the background of the guide magnetic field, thereby offsetting the compensating magnetic field and forming a demagnetizing region. A precessing magnetic field, orthogonal to the guide and compensating magnetic fields, is then generated via a second coil. This precessing magnetic field achieves neutron polarization flipping through Larmor precession, and also achieves neutron polarization flipping in the demagnetizing region through polarization precession. Since only the guide magnet, the first coil, and the second coil are required to generate the guide magnetic field, the compensating magnetic field, and the precessing magnetic field, respectively, neutron polarization flipping can be achieved based on Larmor precession, resulting in a simple structure and easy implementation of the neutron polarization flipper. Furthermore, once the first and second coils are energized, they can generate a magnetic field for neutron polarization flipping, thereby increasing the flipping speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of the neutron polarization flipper;

[0026] Figure 2 is a structural schematic diagram of a guide magnet in another embodiment;

[0027] Figure 3 A schematic structural diagram of a flip bracket according to an embodiment;

[0028] Figure 4 A framework diagram of a neutron polarization reversal device according to an embodiment;

[0029] Figure 5 Schematic diagram of output current change of a driving device according to an embodiment. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below by means of specific embodiments in conjunction with the accompanying drawings. Similar elements in different embodiments are numbered with associated similar elements. In the following embodiments, many detailed descriptions are provided to enable the present application to be better understood. However, those skilled in the art will readily appreciate that some of the features may be omitted in different circumstances, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core portion of the present application being overwhelmed by excessive descriptions, and for those skilled in the art, it is not necessary to describe these related operations in detail. They will fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0031] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various embodiments. Furthermore, the steps or actions in the method description may be reordered or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various sequences in the specification and drawings are provided solely for the purpose of clearly describing a particular embodiment and are not intended to be mandatory, unless otherwise specified.

[0032] Component numbers used herein, such as "first" and "second," are used solely to distinguish the components being described and do not convey any sequential or technical meaning. References to "connection" and "coupling" herein, unless otherwise specified, include both direct and indirect connections (couplings).

[0033] In an embodiment of the present invention, a continuous guiding magnetic field is generated by the guiding magnet, and then the compensation magnetic field and precession magnetic field required for neutron polarization reversal are respectively generated by the first coil and the second coil, and then the polarization reversal of the neutron is realized based on the Larmor precession of the neutron. The structure is simple and easy to implement.

[0034] Please refer to Figure 1 In some embodiments, a neutron polarization flipper is provided, which includes a guide magnet 10 and a flip assembly, which will be described in detail below.

[0035] The guide magnet 10 is used to generate a guide magnetic field within a predetermined region. In some embodiments, the guide magnetic field generated by the guide magnet 10 within the predetermined region is a uniform magnetic field. The guide magnetic field is used to guide the polarization vectors of neutrons within the guide magnetic field, and the polarization vectors of the neutrons are always parallel or antiparallel to the guide magnetic field.

[0036] Please refer to Figure 1 and Figure 2 In some embodiments, the guide magnet 10 includes a first group of magnets 12 and a second group of magnets 12a. The first group of magnets 12 and the second group of magnets 12a are arranged oppositely on both sides of the preset area, or in other words, the area between the first group of magnets 12 and the second group of magnets 12a is the preset area, and the first group of magnets 12 and the second group of magnets 12a are placed in parallel, so that the guide magnetic field generated between the first group of magnets 12 and the second group of magnets 12a in the preset area is a uniform magnetic field. In some embodiments, the magnetic poles of the first group of magnets 12 and the magnetic poles of the second group of magnets 12a are arranged opposite each other, that is, the north pole of the first group of magnets 12 is opposite to the south pole of the second group of magnets 12a, and the south pole of the first group of magnets 12 is opposite to the north pole of the second group of magnets 12a, so that the guide magnetic field generated between the first group of magnets 12 and the second group of magnets 12a is a uniform magnetic field. In some embodiments, the first group of magnets 12 and the second group of magnets 12a can be permanent magnets or electromagnets. Since the guiding magnetic field needs to exist stably for a long time, the first group of magnets 12 and the second group of magnets 12a are usually implemented using permanent magnets, such as MdFeB magnets.

[0037] In some embodiments, the guide magnet 10 further includes a first set of magnet brackets 14 and a second set of magnet brackets 14a, while the first set of magnets 12 and the second set of magnets 12a each include a plurality of magnets 122, each being assembled from a plurality of magnets 122. In this embodiment, the first set of magnet brackets 14 and the second set of magnet brackets 14a can have the same structure, and the first set of magnets 12 and the second set of magnets 12a can have the same structure. Therefore, the first set of magnet brackets 14 and the first set of magnets 12 will be described in detail.

[0038] The first set of magnet brackets 14 defines a plurality of mounting slots 142 that mate with the magnets 122, and the plurality of magnets 122 are disposed within the mounting slots 142 of the first set of magnet brackets 14 to form the first set of magnets 12. In some embodiments, the mounting slots 142 are compactly arranged so that the magnets 122 can be individually mounted and placed within the first set of magnet brackets 14 while also forming a larger magnet with adjacent magnets 122. For example, the mounting slots 142 may be bar-shaped, and the magnets 122 may be corresponding bar-shaped magnets. The mounting slots 142 may be compactly arranged side by side, and the plurality of bar magnets placed in different mounting slots 142 may collectively form a larger magnet. In this embodiment, since both the first and second sets of magnets 12, 12a are composed of a plurality of magnets 122, the strength and coverage of the guiding magnetic field generated between the first and second sets of magnets 12, 12a is determined by the number of magnets 122. Specifically, the greater the number of magnets 122, the greater the strength and coverage of the guiding magnetic field. Thus, by placing different numbers of magnets 122 to form first and second sets of magnets 12, 12a of varying sizes, guiding magnetic fields of varying strength and coverage can be generated to suit different applications.

[0039] In some embodiments, the guide magnet 10 further includes a first protective shell 16 and a second protective shell 16a. When a plurality of magnets 122 are placed on the first and second magnet brackets 14, 14a, the first and second magnet brackets 14, 14a can be covered by the first and second protective shells 16, 16a, respectively, thereby shielding the mounting grooves 142 of the first and second magnet brackets 14, 14a, and pressing down the magnets 122 on the first and second magnet brackets 14, 14a. In this embodiment, the addition of the first and second protective shells 16, 16a can not only protect the magnets 122 on the brackets, but also fix the magnets 122 on the brackets to prevent the magnets 122 from moving. In this embodiment, the first protective shell 16, the second protective shell 16a, the first group of magnet brackets 14 and the second group of magnet brackets 14a are all made of aluminum, and the first protective shell 16 and the second protective shell 16a can be fixed to the first group of magnet brackets 14 and the second group of magnet brackets 14a by screws respectively.

[0040] Please refer to Figure 3 The flip assembly includes a flip bracket 20, and a first coil and a second coil (not shown) wound around the flip bracket 20.

[0041] In some embodiments, the flip bracket 20 includes two parallel horizontal winding posts 22 and two vertical winding posts 24, each perpendicular to the horizontal winding posts 22. The two vertical winding posts 24 are respectively arranged parallel to the first group of magnets 12 and the second group of magnets 12a. In this embodiment, the first coil is wound around the two horizontal winding posts 22 in a direction perpendicular to the horizontal winding posts 22. Therefore, when the wound first coil is energized, the compensation magnetic field generated therein is not only a uniform magnetic field, but also parallel to the horizontal winding posts 22. The guide magnetic field generated between the first group of magnets 12 and the second group of magnets 12a is also a uniform magnetic field, but in a direction orthogonal to the first group of magnets 12 and the second group of magnets 12a. Therefore, the compensation magnetic field and the guide magnetic field are in the same horizontal direction, thereby offsetting each other to form a demagnetizing field region. Similarly, the second coil is wound around the two vertical winding rods 24 in a direction orthogonal to the vertical winding rods 24. Therefore, when the wound second coil is energized, the precession magnetic field generated therein is not only a uniform magnetic field, but also parallel to the horizontal winding rods 22. Therefore, the precession magnetic field is orthogonal to the guide magnetic field and the compensation magnetic field, respectively. In some embodiments, the two vertical winding rods 24 are not only arranged parallel to the first and second groups of magnets 12, 12a, respectively, but the two vertical winding rods 24, the first and second groups of magnets 12, 12a are also located on the same straight line, and the two vertical winding rods 24 are located between the first and second groups of magnets 12, 12a. Therefore, the two vertical winding rods 24 are located within a predetermined area, so that the horizontal winding rods 22, the first coil, and the second coil are also located within the predetermined area.

[0042] The first coil is wound around the flip bracket 20 in a spiral shape. When energized, it generates a compensation magnetic field opposite to the guide magnetic field. The guide and compensation magnetic fields form a demagnetizing field in the intersecting region. Because the compensation magnetic field and the guide magnetic field have the same magnetic strength but opposite magnetic directions, they cancel each other out in the intersecting region, resulting in a demagnetizing field with no magnetic field. The second coil is also wound around the flip bracket 20 in a spiral shape. When energized, it generates a precession magnetic field in the demagnetizing field that is orthogonal to the guide and compensation magnetic fields. This precession magnetic field is used to flip the polarization of neutrons entering the precession magnetic field. When the first coil is energized to generate a compensation magnetic field opposite to the guide magnetic field, the second coil is energized to generate a precession magnetic field in the demagnetizing field that is orthogonal to the guide and compensation magnetic fields, thereby flipping the polarization of neutrons through Larmor precession.

[0043] In this embodiment, the flip assembly achieves polarization flipping of neutrons through Larmor precession. The basic principle is that, on the background of the guiding magnetic field generated by the guide magnet 10, a compensating magnetic field, in the opposite direction of the guiding magnetic field, is generated by the first coil, thereby offsetting it and forming a demagnetizing field. A precessing magnetic field, orthogonal to the guiding and compensating magnetic fields, is then generated by the second coil. This allows for polarization flipping of neutrons within the demagnetizing field through polarization precession. The flipping angle is determined by the magnitude of the precessing magnetic field, which in turn is determined by the current flowing through the second coil. In this embodiment, due to its simple structure, the flip assembly is typically only a few centimeters thick, making it ideal for use with short spectrometer lines. In this embodiment, upon energizing the first and second coils, a magnetic field for neutron polarization flipping is generated, thereby increasing the flipping speed to as little as 40 milliseconds, which is faster than other existing polarization flippers.

[0044] In some embodiments, because the flip bracket 20 is located within a predetermined area, the first coil and the second coil are both located within the predetermined area after being wound around the flip bracket 20, thereby generating a compensation magnetic field that is opposite to the guide magnetic field and a precession magnetic field that is orthogonal to the guide magnetic field and the compensation magnetic field, respectively. In other embodiments, a portion of the flip bracket 20 is located within the predetermined area, and the first coil and the second coil are wound around the flip bracket 20 located within the predetermined area, such that both the first coil and the second coil are located within the predetermined area.

[0045] In some embodiments, the two horizontal winding columns 22 and the two vertical winding columns 24 are integrally formed to form a U-shaped flip bracket 20. For example, a U-shaped hollow groove is opened in the middle of a board, so that two horizontal winding columns 22 and two vertical winding columns 24 are formed on the four sides of the board respectively. In some embodiments, the two horizontal winding columns 22 and the two vertical winding columns 24 can also be spliced ​​to form the flip bracket 20, and the two horizontal winding columns 22 and the two vertical winding columns 24 are fastened by screws. In this embodiment, the flip bracket 20 is made of bakelite material, which has high mechanical strength, good insulation, heat resistance and corrosion resistance. In some embodiments, the two horizontal winding columns 22 or the two vertical winding columns 24 are extended to form a mounting block 26 exposed from the flip bracket 20, and then the flip bracket 20 is installed and fixed by the mounting block 26.

[0046] Please refer to Figure 1In some embodiments, the neutron polarization flipper further includes two support plates 30 and four mounting brackets 40, wherein one end of two of the mounting brackets 40 clamps one end of one of the support plates 30, and the other ends of two of the mounting brackets 40 clamp one end of another support plate 30, and one end of another two mounting brackets 40 clamps the other end of one of the support plates 30, and the other ends of another two mounting brackets 40 clamp the other end of another support plate 30. In this embodiment, both ends of the mounting brackets 40 are provided with a slot 42 that matches the thickness of the support plate 30, so that the two mounting brackets 40 can better clamp the support plate 30. After clamping, the two mounting brackets 40 can be connected by a connecting block and fixed by screws. In this embodiment, the mounting brackets 40 are made of bakelite, which has high mechanical strength, good insulation, heat resistance, and corrosion resistance. In this embodiment, two sides of the support plate 30 are provided with retaining grooves 32 that match the thickness of the mounting brackets 40. When the two mounting brackets 40 clamp the support plate 30, the two mounting brackets 40 are respectively engaged in the retaining grooves 32, thereby preventing the two mounting brackets 40 from being easily moved. In some embodiments, the support plate 30 is made of carbon steel.

[0047] In some embodiments, the first group of magnet brackets 14 and the second group of magnet brackets 14a of the guide magnet 10 are respectively fixed between two support plates 30. The two support plates 30 have placement grooves 34 on opposite sides, and the two ends of the first group of magnet brackets 14 and the second group of magnet brackets 14a are respectively connected to the placement grooves 34 between the two support plates 30, and are installed and fixed by clamping the two support plates 30. In this embodiment, the flip bracket 20 is fixed on at least one mounting bracket 40. The flip bracket 20 is installed on the mounting bracket 40 through a mounting block and fastened by screws. The flip bracket 20 can only be stably installed if it is fixed to at least one mounting bracket 40 through a mounting block. In this embodiment, through the clamping installation between two support plates 30 and four mounting brackets 40, an installation structure for fixing the guide magnet 10 and the flip assembly can be quickly built, which is simple to install and easy to operate.

[0048] Please refer to Figure 1 and Figure 4 In some embodiments, a neutron polarization reversal device is provided. In addition to the neutron polarization reversal device in the above embodiments, the neutron polarization reversal device also includes a driving device 50.

[0049] The drive device 50 is configured to output a current to the first coil, causing the first coil to generate a compensating magnetic field that is opposite to the guiding magnetic field, with the compensating magnetic field and the guiding magnetic field being uniform magnetic fields of equal strength. In some embodiments, the drive device 50 is further configured to output a current to the second coil, causing the second coil to generate a precessing magnetic field that is orthogonal to the guiding magnetic field and the compensating magnetic field, respectively. The strengths of the compensating magnetic field and the precessing magnetic field are related to the amplitude of the current output by the drive device 50.

[0050] In some embodiments, the driving device 50 includes a signal generator 52 and a current amplifier 54. The signal generator 52 is configured to output a voltage signal, and the power amplifier is configured to generate a corresponding current signal based on the voltage signal output by the signal generator 52 to power the first and second coils. For example, the amplitude range of the output of the signal generator 52 is -10V to +10V, while the power amplifier correspondingly generates a current signal ranging from 0A to 20A. Therefore, the power amplifier functions as a voltage-controlled current source, varying the output current as the output voltage of the signal generator 52 changes. The driving device 50 generates a control voltage signal to control the current amplifier 54 to generate a current signal of sufficient amplitude to generate a magnetic field of a corresponding strength for the first and second coils.

[0051] In some embodiments, the drive device 50 is configured to output a constant current to the first coil, such that the compensation magnetic field generated by the first coil is a constant uniform magnetic field. In some embodiments, the drive device 50 is configured to output a constant current to the second coil, such that the precession magnetic field generated by the second coil has a constant intensity. Since the flip angle of a neutron entering the precession magnetic field is determined by the intensity of the precession magnetic field, when the intensity of the precession magnetic field is constant, the flip angle of the neutron is also fixed.

[0052] Please refer to Figure 5In some embodiments, the drive device 50 is configured to output a varying current to the second coil, causing the second coil to generate a precessing magnetic field of varying strength, with the rate of change in strength being less than a preset value, typically less than the precession velocity of the neutron. In this embodiment, since the spin of the polarized neutron changes during transmission due to the spin direction and magnetic field direction, this is non-adiabatic transmission, i.e., the process of neutrons being transmitted from the guide magnetic field to the precessing magnetic field. However, since the angle is changed through Larmor precession, the angle between the neutron spin and the magnetic field direction does not change during this process. Therefore, the angle change occurs through adiabatic rotation, i.e., the process of neutrons being flipped by the precessing magnetic field. In this embodiment, when the precessing magnetic field performs a polarization flip on the neutron, the precessing magnetic field changes from the initial magnetic field strength to the preset magnetic field strength, and then from the preset magnetic field strength to the initial magnetic field strength. For example, when the preset magnetic field strength is less than the initial magnetic field strength, the precessing magnetic field decreases from the initial magnetic field strength to the preset magnetic field strength, and then increases from the preset magnetic field strength to the initial magnetic field strength, to complete the polarization flip of the neutron. Since the flip angle of neutrons entering the precession magnetic field is determined by the strength of the precession magnetic field, the flip angle of the neutrons also changes when the strength of the precession magnetic field changes. For example, when the preset magnetic field strength is less than the initial magnetic field strength, the neutrons will first flip by an angle related to the initial magnetic field strength. When the precession magnetic field decreases from the initial magnetic field strength to the preset magnetic field strength, the neutron flip angle will twist back to an angle related to the preset magnetic field strength. Finally, when the precession magnetic field is increased from the preset magnetic field strength to the initial magnetic field strength, the neutron flip angle will twist back to an angle related to the initial magnetic field strength, thereby achieving a neutron flip efficiency greater than 99%. In some embodiments, when the precession magnetic field changes from the initial magnetic field strength to the preset magnetic field strength and then back to the initial magnetic field strength, the magnetic field strength can change in a uniform linear manner or in a non-uniform curved manner, as long as the rate of change is less than the precession velocity of the neutrons.

[0053] Please refer to Figure 4 In some embodiments, the driver 50 is configured to output current to the first and second coils after receiving a target control signal from the accelerator. In this embodiment, the accelerator generates a target control signal and outputs it to the driver 50 only when neutrons are emitted into the precession magnetic field. The driver 50 then outputs corresponding currents to the first and second coils based on the target control signal. This ensures that only when neutrons are about to enter the precession magnetic field will the first and second coils generate a compensation magnetic field and a precession magnetic field, respectively, and perform polarization flipping on neutrons entering the precession magnetic field. In some embodiments, the accelerator generates a target control signal and outputs it to the signal generator 52, which controls the signal generator 52 to output a corresponding voltage, thereby controlling the current amplifier 54 to output a corresponding current.

[0054] In the above embodiment, a mounting structure for securing the guide magnet 10 and the flip assembly is first constructed using two support plates 30 and four mounting brackets 40. The guide magnet 10 is then mounted between the two support plates 30, and the flip assembly is mounted on the mounting brackets 40. At this point, the guide magnet 10 generates a guide magnetic field within a predetermined region. When the accelerator launches neutrons toward the flip assembly, a target control signal is generated and output to the drive device 50. The drive device 50 then outputs corresponding currents to the first coil and the second coil, causing the first coil to generate a compensation magnetic field in the opposite direction of the guide magnetic field, which offsets the compensation magnetic field and forms a demagnetizing field. The second coil then generates a precession magnetic field in the demagnetizing field, which is orthogonal to the guide magnetic field and the compensation magnetic field. This allows the neutron polarization to be flipped through Larmor precession. Firstly, the guide magnet 10, the first coil, and the second coil only need to generate the guide magnetic field, the compensation magnetic field, and the precession magnetic field, respectively, to achieve polarization flipping of the neutron based on Larmor precession. This makes the neutron polarization flipper simple in structure and easy to implement. Secondly, the guide magnet 10 and flip assembly are mounted using two support plates 30 and four mounting brackets 40, making installation simple and easy. Thirdly, upon receiving the accelerator's target firing control signal, the drive device 50 outputs a corresponding current, causing the flip assembly to generate the required magnetic field, thereby achieving neutron flipping in sync with the target firing control signal.

[0055] The above examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. Those skilled in the art can make several simple deductions, modifications or substitutions based on the concept of the present invention.

Claims

1. A neutron polarization flipper, characterized in that: include: A guide magnet, used to generate a guide magnetic field in a preset area; A flip assembly, comprising a flip bracket, a first coil and a second coil; The first coil and the second coil are wound around the flip bracket and are arranged in the preset area. The first coil is used to generate a compensation magnetic field opposite to the guide magnetic field when energized, so that the guide magnetic field and the compensation magnetic field form a demagnetizing field area in the intersecting area. The second coil is used to generate a precession magnetic field orthogonal to the guide magnetic field and the compensation magnetic field in the demagnetizing field area when energized. The precession magnetic field is used to perform polarization flipping on neutrons entering the precession magnetic field. The guide magnet includes a first group of magnets and a second group of magnets; the first group of magnets and the second group of magnets are arranged on both sides of the preset area relative to each other, and the first group of magnets and the second group of magnets are placed in parallel, so that the guide magnetic field generated between the first group of magnets and the second group of magnets in the preset area is a uniform magnetic field; the guide magnet also includes a first group of magnet brackets and a second group of magnet brackets; The first group of magnets and the second group of magnets each include a plurality of magnets, the first group of magnet brackets and the second group of magnet brackets each have a plurality of mounting slots matching the magnets, and the plurality of magnets are respectively arranged in the mounting slots of the first group of magnet brackets and the second group of magnet brackets to form the first group of magnets and the second group of magnets respectively; The flip bracket includes two horizontal winding columns parallel to each other, and two vertical winding columns perpendicular to the horizontal winding columns; the first coil is wound on the two horizontal winding columns in a direction perpendicular to the horizontal winding columns, and the second coil is wound on the two vertical winding columns in a direction orthogonal to the vertical winding columns. The two vertical winding columns are respectively arranged parallel to the first group of magnets and the second group of magnets.

2. The neutron polarization flipper according to claim 1, characterized in that: The two horizontal winding columns or the two vertical winding columns are extended to form a mounting block exposed from the flip bracket, and the mounting block is used for mounting and fixing the flip bracket.

3. The neutron polarization flipper according to claim 1, characterized in that: The current output by the driving device received by the second coil when performing a polarization flip on the neutron is variable, so as to generate the precession magnetic field with varying magnetic field strength, and the intensity change rate of the precession magnetic field is less than a preset value.

4. The neutron polarization flipper according to claim 3, characterized in that: The magnetic field strength of the precession magnetic field changes from the initial magnetic field strength to the preset magnetic field strength, and then changes from the preset magnetic field strength to the initial magnetic field strength.

5. The neutron polarization flipper according to claim 1, characterized in that: The second coil is used to receive the current output by the driving device when neutrons are emitted toward the precession magnetic field, so as to generate the precession magnetic field.

6. The neutron polarization flipper according to claim 1, characterized in that: It also includes two support plates and four mounting brackets, wherein one end of two of the mounting brackets clamps one end of one of the support plates, the other ends of two of the mounting brackets clamp one end of the other support plate, one end of another two of the mounting brackets clamps the other end of one of the support plates, and the other ends of another two of the mounting brackets clamp the other end of another support plate, the guide magnet is fixed between the two support plates, and the flip bracket is fixed on at least one of the mounting brackets.

7. A neutron polarization reversal device, characterized in that: comprising a driving device and the neutron polarization flipper according to any one of claims 1 to 6; The driving device is used to output current to the first coil after receiving the target control signal of the accelerator, so as to generate a compensation magnetic field opposite to the guide magnetic field, and form a demagnetizing field area in the intersecting area between the guide magnetic field and the compensation magnetic field. The driving device is also used to output current to the second coil, so as to generate a precession magnetic field orthogonal to the guide magnetic field and the compensation magnetic field in the demagnetizing field area, and the precession magnetic field is used to perform polarization reversal on neutrons entering therein.

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