A Helium-3 Neutron Polarization Device

Abstract

The present invention relates to the field of neutron polarization technology, and specifically to a helium-3 neutron polarization device. The helium-3 neutron polarization device of the present application includes a polarization component, a heating component, a magnetic field component, and a laser component. Among them, a sealed polarization cavity is formed inside the polarization component for containing helium-3 gas, the heating component is used to heat the polarization component to provide a high temperature environment required for the polarization of helium-3 gas, the magnetic field component is arranged on the periphery of the polarization component to provide a stable polarization magnetic field for the polarization process, and the laser component is used to introduce circularly polarized light into the polarization cavity to provide photons for the polarization of the helium-3 atoms, so that the process of alkali metal atoms absorbing photons and transitioning continues, and continuously collides with helium-3 atoms to complete polarization transfer, and finally realizes the polarization of helium-3 atoms, and then polarizes neutrons.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron polarization, and in particular to a helium-3 neutron polarization device. Background Art

[0002] Neutrons are 1 / 2 spin particles with magnetic dipole moments, so they can be polarized to produce polarized neutron beams. Polarized neutron scattering has unparalleled advantages over any other technology in the study of magnetic materials. It is the only detection technology that can distinguish magnetic scattering from nuclear scattering without distinction. Among the current mainstream neutron polarization technologies, the polarized helium-3 neutron spin filter device has significant advantages such as large receiving angle, high polarization rate, low background, wide energy spectrum, and uniform polarization and analysis capabilities, making it the mainstream choice for achieving neutron polarization. In the SEOP method of helium-3 neutron polarization method, the polarization of helium-3 is directly achieved under high pressure (1-10bar). First, the outermost electrons of alkali metals are polarized, and then the polarization is transferred to the nuclear spin of helium-3 atoms by spin exchange. Due to its advantages of being usable in a multi-wavelength range, large receiving angle, and being able to be used as a polarization flipper and polarization analyzer at the same time, it is the most suitable polarizer for spallation neutron sources. In the in-situ system in the laboratory, the spin polarization rate of neutrons will decrease over time, which will affect the experiment. For example, the measurement of magnetic imaging requires a long measurement time, so the neutron spin polarization must remain stable for several days. The in-situ system is not easy to transport, and its polarization decays rapidly over time. Therefore, it is necessary to design a corresponding online polarized He-3 neutron spin filter system and maintain the stable polarization of the neutron beam throughout the process to complete the polarized neutron experiment. Summary of the invention

[0003] The invention provides a helium-3 neutron polarization device, the purpose of which is to stably polarize neutrons online.

[0004] A helium-3 neutron polarization device, comprising: a polarization component, a heating component, a magnetic field component and a laser component;

[0005] A sealed polarization cavity is formed inside the polarization assembly for containing helium-3 gas and alkali metal;

[0006] The heating component is used to heat the polarization component to provide a required temperature environment for the polarization of the helium-3 gas;

[0007] The magnetic field component is arranged at the periphery of the polarization component to form a stable polarization magnetic field;

[0008] The laser assembly is used to introduce circularly polarized light into the polarization cavity to provide photons for polarization of the helium-3 gas.

[0009] In one embodiment, the heating assembly includes a heating cylinder and a heating pipe, and the heating pipe is filled with heated gas;

[0010] Alternatively, the heating assembly includes a heating cylinder and a heating controller, and the heating controller is a duct-type heating controller that utilizes air flow through a closed heating surface for heating.

[0011] In one embodiment, the magnetic field assembly includes an AFP coil assembly and a main magnetic field assembly;

[0012] The AFP coil assembly comprises a first cylinder and an AFP coil wound on the first cylinder, wherein the AFP coil is wound on the outer wall of the first cylinder along the axial direction of the first cylinder;

[0013] The main magnetic field assembly comprises a second cylinder and a main coil wound on the outer wall of the second cylinder, and the main coil is wound on the outer wall of the second cylinder along the circumferential direction.

[0014] In one embodiment, the main magnetic field assembly further includes two auxiliary coils, both of which are wound around the periphery of the main coil along the circumferential direction and are respectively located at two ends of the second cylinder.

[0015] In one embodiment, it further comprises a cooling water pipe, wherein the cooling water pipe is wound around the periphery of the heating cylinder;

[0016] It also includes a circular support member, on which a sapphire sheet is provided, the support member is arranged at both ends of the first cylinder, the second cylinder is sleeved outside the first cylinder, and the periphery of the support member is in contact with the inner wall of the second cylinder;

[0017] The cooling water pipe is located between the heating cylinder and the first cylinder, and is used for thermally isolating the AFP coil assembly and the main magnetic field assembly.

[0018] In one embodiment, it also includes a Permalloy sleeve and a packaging round cover, wherein the Permalloy sleeve is sleeved on the periphery of the main magnetic field assembly, the packaging round covers are arranged at both ends of the Permalloy sleeve, a through hole is provided on the packaging round cover, the center of the through hole, the center of the sapphire sheet and the axis of the heating cylinder are on the same optical path, and the polarization assembly is arranged in the cavity of the heating cylinder.

[0019] In one embodiment, the laser assembly includes a laser, a lens, a polarization beam splitter and a quarter wave plate, and a reflector;

[0020] The laser is used to emit laser light of a fixed wavelength (for example, 795 nm), and the lens, polarization beam splitter and quarter wave plate are sequentially arranged on the optical path to separate the laser light of the fixed wavelength into left-handed circularly polarized light and right-handed circularly polarized light, and to allow the left-handed circularly polarized light and the right-handed circularly polarized light to be respectively emitted into the polarization cavity from the through holes on the packaging round cover, wherein the reflector is used to change the direction of the optical path.

[0021] In one embodiment, it also includes a box body, the polarization component, the heating component, and the magnetic field component are all arranged in the box body, and a transmission part is respectively provided on a set of opposite side walls of the box body, and the center of the transmission part, the hole center of the through hole on the packaging circular cover, and the axis center of the heating cylinder are all on the same optical path;

[0022] The laser is arranged outside the box, the lens, polarization beam splitter and quarter wave plate are all arranged inside the box, and the box is also provided with a through hole for neutrons to pass through.

[0023] In one embodiment, a gas connecting pipe is provided on the box body, the inner port of the gas connecting pipe is communicated with the heating pipe, and the outer port is used to connect to the heating box;

[0024] The box body is also provided with a liquid connecting pipe, the inner end of which is connected to the cooling water pipe, and the outer end of which is used to connect to the water cooler;

[0025] The box body is also provided with a BNC connector, and the heating cylinder in the box body is also provided with a temperature sensor, the temperature sensor is electrically connected to the BNC connector, and the BNC connector is used to connect a temperature measuring instrument and a magnetic field wiring;

[0026] At least one heat dissipation fan is also arranged in the box.

[0027] In one embodiment, the box body is composed of a movable cover plate, and a pressure plate sensor is provided on the movable cover plate, and the pressure plate sensor is electrically connected to the controller;

[0028] A photodiode is also provided near the emission point of the laser, and the photodiode is also electrically connected to the controller;

[0029] The polarization assembly is also provided with an F ID coil and an EPR coil, wherein the F ID coil is used to measure the relative polarizability in the polarization cavity, and the EPR coil is used to measure the absolute polarizability;

[0030] It also includes a mounting tube, a D2 filter and a photodiode, wherein the mounting tube is arranged on the box body, one end of which is aligned with the polarization component, the photodiode is arranged at the other end of the mounting tube, and the D2 filter is arranged in the mounting tube;

[0031] The cooling water pipe is also provided with a flow switch, and the flow switch is also electrically connected to the controller.

[0032] According to the above-mentioned embodiment, the helium-3 neutron polarization device includes a polarization component, a heating component, a magnetic field component and a laser component. Among them, a sealed polarization cavity is formed inside the polarization component for containing helium-3 gas, the heating component is used to heat the polarization component to provide the required high temperature environment for the polarization of helium-3 gas, the magnetic field component is arranged on the periphery of the polarization component to provide a stable polarization magnetic field for the polarization process, and the laser component is used to introduce circularly polarized light into the polarization cavity to provide photons for the polarization of the helium-3 gas, so that the process of alkali metal atoms absorbing photons and transitioning continues, and continuously collides with helium-3 atoms to complete polarization transfer, and finally realizes the polarization of helium-3 atoms, and then polarizes neutrons. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the overall structure of the polarization device of an embodiment of the present application;

[0034] Figure 2 An exploded view of a heating component and a magnetic field component of a polarization device according to an embodiment of the present application;

[0035] Figure 3 A schematic diagram of the structure of a polarization device according to an embodiment of the present application;

[0036] Figure 4 A schematic diagram of the structure of a laser assembly according to an embodiment of the present application;

[0037] Figure 5 A schematic diagram of the structure of a polarization device according to an embodiment of the present application at a viewing angle;

[0038] Figure 6 This is a schematic diagram of the structure of the heating assembly and the cooling water pipe of an embodiment of the present application;

[0039] Figure 7 This is a schematic structural diagram of an AFP coil assembly according to an embodiment of the present application;

[0040] Figure 8 This is a schematic diagram of the structure of the main magnetic field assembly of an embodiment of the present application;

[0041] Fig. 9 This is a schematic diagram of the structure of an interlocking control system according to an embodiment of the present application;

[0042] Fig.10 This is a working diagram of the interlocking control system according to an embodiment of the present application;

[0043] Fig.11 Schematic diagram of the optical path of an embodiment of the present application. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, 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 part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0045] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0046] The serial numbers assigned to the components in this article, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning.

[0047] The helium-3 neutron polarization device of the present application uses the spin-exchange optical pumping technology SEOP (Spin-exchange optical pumping). The basic principle is that when neutrons pass through the helium-3 gas that is continuously polarized by laser pumping, the polarized gas has an absorption cross-section for neutrons whose spins are antiparallel to the helium-3 that is approximately three orders of magnitude higher than the absorption cross-section for neutrons whose spins are parallel to the helium-3 spin. This feature is used to achieve the polarization of the neutron beam.

[0048] Embodiment 1:

[0049] Please refer to Figure 1 This embodiment provides a helium-3 neutron polarization device, which mainly includes: a polarization component, a heating component 1, a magnetic field component and a laser component.

[0050] Among them, Figure 3The polarization component 1 is a sealed glass container, which is a sealed polarization cavity. The polarization cavity is used to contain helium-3 gas and alkali metal gas. The glass container is provided with an injection port, which is used to inject helium-3 gas and alkali metal gas. At the same time, the glass container is also provided with an F ID coil 12, which is used to measure the relative polarizability in the glass container; the system also includes a mounting tube 14, an EPR coil 13, a photodiode and a D2 filter 15, wherein the EPR coil 13 is arranged outside the glass container for applying a radio frequency field, the photodiode 16 is used to detect fluorescence signals, and the D2 filter 15 is used to filter lasers. The method is used to measure the absolute polarizability in the glass container. The heating component is arranged around the polarization component 1 to uniformly heat the polarization cavity 1 of the polarization component 1, to provide a stable temperature environment for the polarization of helium-3 gas, so as to ensure the stable polarization. The magnetic field component is arranged on the periphery of the polarization component, to form a stable magnetic field, to provide a stable magnetic field environment for neutron polarization. The laser component is used to pass circularly polarized light into the polarization cavity to provide photons for the polarization of helium-3 gas. The process of photon absorption transition of helium-3 atoms continues to proceed, so as to complete the stable polarization of neutrons. In order to ensure the efficient filtration of polarized helium-3 to neutrons, the polarization cavity should have the characteristics of high temperature resistance, non-magnetic, light transmission and low permeability, so glass should be selected as the container of helium-3 gas. The magnetic susceptibility of the polarization cavity is measured by the free decay induction FID (Free Induction Decay) technology of nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) technology to measure the relative polarizability and absolute polarizability respectively, while the adiabatic fast channel AFP (Ad i abat ic Fast Passage) technology of the NMR method can change the spin direction of neutrons.

[0051] Among them, Figure 2 The heating assembly of this embodiment includes a heating cylinder 21 and a heating pipe arranged outside the heating cylinder 21, wherein the heating cylinder 21 is made of PEEK (polyetheretherketone) material, and heated gas is passed into the heating pipe to continuously heat the heating cylinder 21, so that a stable high-temperature environment is maintained in the polarization cavity, and the high-temperature environment is used to vaporize the alkali metal into steam. Then, the outer layer of the heating pipe is first wrapped with glass fiber of appropriate thickness to achieve the effect of heat preservation without heat dissipation.

[0052] The magnetic field assembly of this embodiment includes an AFP coil assembly and a main magnetic field assembly, such as Figure 7The winding directions of the coils on the AFP coil assembly and the main magnetic field assembly are perpendicular to each other, so as to provide mutually perpendicular magnetic fields to achieve neutron flipping. Specifically, the AFP coil assembly includes a first cylinder 31 and an AFP coil wound on the first cylinder 31. A plurality of gaskets 32 are arranged on the first cylinder 31 along the axial direction, and the AFP coil is wound around the gaskets 32. In this way, the AFP coil 32 is wound on the outer wall of the first cylinder 31 along the axial direction of the first cylinder 31. After the AFP coil is energized, it can provide a magnetic field along the first direction. Figure 8 The main magnetic field assembly includes a second cylinder 41 and a main coil 42 wound on the outer wall of the second cylinder 41. The main coil 42 is wound on the outer wall of the second cylinder 41 along the circumferential direction, so that when the main coil 42 is energized, a magnetic field along the second direction is formed, and the first direction is perpendicular to the second direction, that is, two mutually perpendicular magnetic fields are formed.

[0053] Furthermore, in order to form a uniform magnetic field along the second direction, the main magnetic field assembly of this embodiment also includes two auxiliary coils 43. The two auxiliary coils 43 are both wound around the periphery of the main coil 42 along the circumferential direction and are respectively located at two ends of the second cylinder 41.

[0054] The main magnetic field in the magnetic field is used to define the direction of polarization, while the secondary coil 43 is used to apply a weak transverse field pulse, and then the polarization rate of helium-3 is calculated by the measurement system. The main magnetic field must meet The relaxation time can be guaranteed to be long enough. In the experiment, a magnetic field coil is used inside the magnetic shielding shell to provide a uniform main magnetic field for the polarization system, and the uniformity of the magnetic field is ensured by adding auxiliary coils 43 on both sides of the main coil.

[0055] During operation, the magnetic field assembly needs to be mounted on the heating assembly to provide a uniform magnetic field. This is to prevent the heat generated by the heating assembly from damaging the Permalloy and affecting its magnetic shielding properties. Figure 6 In this embodiment, a cooling water pipe 22 is also provided. The cooling water pipe 22 is wound around the periphery of the heating pipe and is made of Teflon material. Specifically, a cavity with a gap is formed between the heating pipe and the cooling water pipe 22, that is, the cooling water pipe 22 is ensured not to be in direct contact with the heating pipe, thus avoiding affecting the heating efficiency.

[0056] In order to avoid too fast heat loss, sapphire sheets are also provided at both ends of the first cylinder 31 in this embodiment. The sapphire sheet 62 is relatively thin, so it is fixed and supported by the circular support member 61. The sapphire sheet 62 is installed at the center of the support member. The support member 61 is fixed to both ends of the first cylinder 31 by screws. The second cylinder 41 is sleeved outside the first cylinder 31, and the surrounding of the support member 61 is in contact with the inner wall of the second cylinder 41. The cooling water pipe 22 is located between the heating cylinder 21 and the first cylinder 31, and plays a role of magnetic shielding for the AFP coil assembly, the main magnetic field assembly and the Permalloy. The sapphire sheet 62 can ensure that neutrons and lasers pass through. The through hole of the circular support member 61 is equipped with a sapphire sheet 62 for light transmission, heat preservation, and ensuring high neutron transmittance and reducing the background.

[0057] In order to shield the external magnetic field, the device of this embodiment also includes a Permalloy sleeve 53 and a packaging round cover 51. The Permalloy sleeve 53 is sleeved on the periphery of the main magnetic field component, that is, sleeved on the outer wall of the main coil 42. The packaging round cover 51 is arranged at both ends of the Permalloy sleeve 53. The packaging round cover 51 is provided with a through hole 52 for laser and neutron to pass through. The center of the through hole 52, the center of the sapphire sheet 62 and the axis of the cylindrical cavity inside the heating cylinder 21 are all on the same optical path, and the polarization component is arranged in the cavity of the heating cylinder 21. Since there are many ferromagnetic objects on the neutron spectrometer line, the magnetic field environment on the spectrometer is more complex than that in the laboratory, which leads to a shortened depolarization time. The Permalloy sleeve 53 made of magnetic shielding material with high magnetic permeability designed in this embodiment can shield the complex electromagnetic environment on the spectrometer.

[0058] like Figure 4 The laser assembly of this embodiment includes a laser 8, a lens 81, a polarization beam splitter 82, a quarter wave plate 84 and a plurality of reflectors 83. Fig.11The laser 8 is used to emit a laser with a fixed wavelength. The lens, polarization beam splitter 82 and quarter wave plate 84 are arranged in sequence on the laser light path. In addition, a plurality of reflectors 83 are arranged on the light path. The laser beam emitted from the laser 8 is a laser with a fixed wavelength (e.g. 795 nm). After being transmitted by the optical fiber, it is shaped into parallel light by the lens. Then, a polarization beam splitter (also called a standard beam splitter PBS (polarized beam splitter)) 82 is used to separate the linearly polarized P light in the vertical direction and the linearly polarized S light in the horizontal direction. The separated linearly polarized light is converted into circularly polarized light by a quarter wave plate (QWP) 84, wherein the P light is converted into right-handed circularly polarized light and the S light is converted into left-handed circularly polarized light. At this time, the reflector 83 made of coated silicon wafer material is used to adjust the beam path to the same horizontal line as the polarization cavity, so that the two lights in different directions are irradiated into the polarization cavity at the same time along a symmetrical path. When the laser assembly is performing neutron spin filtering, it will be continuously turned on so that the process of alkali metal atoms absorbing photons and transitioning will continue.

[0059] Furthermore, the device of this embodiment also includes a box 7, and the polarization component, the heating component, and the magnetic field component are all arranged in the box 7. A neutron transmission part is respectively provided on a set of opposite side walls of the box 7, and the transmission part is a silicon wafer 71. The center of the silicon wafer 71, the center of the through hole 52 on the packaging round cover 51, the axis of the heating cylinder 21, and the center of the sapphire wafer 62 are all on the same optical path.

[0060] The laser 8 of this embodiment is arranged outside the bottom of the box 7, and the lens, polarization beam splitter 82, reflector 83 and quarter wave plate 84 are all arranged inside the box 7. A through hole is also provided on the bottom of the box 7 for the laser to pass through.

[0061] like Figure 5 In this embodiment, a gas connecting pipe 74 is provided on the box body 7. The inner port of the gas connecting pipe 74 is connected to the heating pipeline, and the outer port is used to connect the heating box 73. The heating box 73 is used to generate a heated airflow. A liquid connecting pipe 75 is also provided on the box body 7. The inner port of the liquid connecting pipe 75 is connected to the cooling water pipe 22, and the outer end is used to connect the water chiller to provide circulating cooling water for thermal isolation. A BNC connector 76 is also provided on the box body 7. A temperature sensor 11 is also provided on the inside of the heating cylinder 21 in the box body 7 or on the outer wall of the polarization component. For example, a thermocouple is provided. The temperature sensor 11 is electrically connected to the BNC connector 76. The BNC connector is used to connect a thermometer to measure the temperature information inside the polarization component 1 in real time so as to monitor the temperature. A cooling fan 72 is also provided at the four corners of the inner wall of the upper cover of the box body 7, respectively, to dissipate heat inside the box body 7.

[0062] The box body 7 of this embodiment is composed of a movable cover plate, which is mounted on an aluminum alloy frame. The movable cover plate is made of aluminum plate, and the bottom of the frame is a breadboard for fixing optical elements, polarization component 1, heating component, magnetic field component and laser component. The wiring is connected to the measuring instrument through the BNC connector 76 on the aluminum plate, and the air pipe and water pipe are also connected to the gas connecting pipe 74 and liquid connecting pipe 75 on the aluminum plate through the water hole and air hole on the aluminum plate. The two plates corresponding to the transmitted neutron are reserved for mounting the N-type silicon chip 71 to filter the external impurity light and prevent the internal laser from leaking, and the fan 72 is designed to dissipate heat for the online system to prevent the system from overheating.

[0063] Among them, the online system must ensure the safety of the staff and the long-term safe operation of the system at the same time, so a safety interlock control device must be added to the system. When an accident occurs, the laser interlock control system can quickly and reliably make corresponding actions to avoid damage to personnel and machinery and equipment. This embodiment also has a laser interlock system, such as Fig. 9 The laser interlocking system includes a controller. A pressure plate sensor is provided on the movable cover 7, and the pressure plate sensor is electrically connected to the controller; when the laser is running, the box is tightly closed to maintain the airtightness of the laser, and when the laser stops, the movable cover can be opened for inspection and maintenance. Fig.10 In order to prevent the movable cover from being opened during the operation of the laser 8, or to start the laser 8 when the movable cover is not in place, a pressure plate sensor is provided on all movable covers. As long as any cover is not in place, the laser will not be able to start or will be automatically shut down.

[0064] A photodiode is also provided at the emission point of the laser 8, and the photodiode is also connected to the controller; the photodiode is used to detect the laser, and once the photodiode detects a laser leak, the laser 8 will be stopped immediately. There is also a flow switch on the cooling water pipe, and the flow switch is also connected to the controller. The laser 8 generates a lot of heat when working. In order to prevent the laser from being damaged due to overheating, the heat generated by the laser 8 needs to be taken away by cooling water. Therefore, a flow switch is set up on the cooling water pipeline. The flow switch can detect the cooling water flow in real time. Once the cooling water flow is lower than the threshold or the flow switch is closed, the system will immediately shut down the laser 8.

[0065] When the system loses power, the power switch will automatically turn off to ensure that the laser is still off when the power is restored. The mode of the laser interlock control system requires the operator to use the safety key to switch between "debugging mode" and "running mode". When the safety key is in debug mode, the control system enters debug mode, and the interlock control system is turned off. When the safety key is in run mode, the system enters interlock state, and the interlock control system is turned on.

[0066] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. A helium-3 neutron polarization device, characterized in that: include: Polarization assembly, heating assembly, magnetic field assembly, laser assembly, cooling water pipe and circular support; A sealed polarization cavity is formed inside the polarization assembly for containing helium-3 gas and alkali metal gas; The heating component is used to heat the polarization component to provide a required temperature environment for the polarization of the helium-3 gas; the heating component includes a heating cylinder and a heating pipe, and the heated gas is passed into the heating pipe; The magnetic field assembly is arranged at the periphery of the polarization assembly, and is used to form a stable polarization magnetic field; the magnetic field assembly includes an AFP coil assembly and a main magnetic field assembly; the AFP coil assembly includes a first cylinder and an AFP coil wound on the first cylinder, and the AFP coil is wound on the outer wall of the first cylinder along the axial direction of the first cylinder; the main magnetic field assembly includes a second cylinder, two secondary coils and a main coil wound on the outer wall of the second cylinder, and the main coil is wound on the outer wall of the second cylinder along the circumferential direction; the two secondary coils are both wound around the periphery of the main coil along the circumferential direction, and are respectively located at the positions of the two ends of the second cylinder; The laser assembly is used to introduce circularly polarized light into the polarization cavity to provide photons for polarization of the helium-3 gas; The cooling water pipe is wound around the periphery of the heating cylinder; a sapphire sheet is provided on the support member, the support member is arranged at both ends of the first cylinder, the second cylinder is sleeved outside the first cylinder, and the four sides of the support member are in contact with the inner wall of the second cylinder; the cooling water pipe is located between the heating cylinder and the first cylinder, and is used to thermally isolate the AFP coil assembly and the main magnetic field assembly.

2. The helium-3 neutron polarization device according to claim 1, characterized in that: It also includes a Permalloy sleeve and a packaging round cover, wherein the Permalloy sleeve is sleeved on the periphery of the main magnetic field component, the packaging round covers are arranged at both ends of the Permalloy sleeve, a through hole is arranged on the packaging round cover, the center of the through hole, the center of the sapphire sheet and the axis of the heating cylinder are on the same optical path, and the polarization component is arranged in the cavity of the heating cylinder.

3. The helium-3 neutron polarization device according to claim 2, characterized in that: The laser assembly includes a laser, a lens, a polarization beam splitter and a quarter wave plate; The laser is used to emit laser light of a fixed wavelength. The lens, polarization beam splitter and quarter wave plate are sequentially arranged on the optical path of the laser to separate the laser light of the fixed wavelength into left-handed circularly polarized light and right-handed circularly polarized light, and to allow the left-handed circularly polarized light and the right-handed circularly polarized light to be respectively emitted into the polarization cavity from the through holes on the packaging round cover.

4. The helium-3 neutron polarization device according to claim 3, characterized in that: It also includes a box body, in which the polarization component, heating component, and magnetic field component are all arranged. A transmission part is respectively provided on a set of opposite side walls of the box body, and the center of the transmission part, the center of the through hole on the packaging circular cover, and the axis of the heating cylinder are all on the same optical path; the box body is also provided with a through hole for the laser to pass through.

5. The helium-3 neutron polarization device according to claim 4, characterized in that: The box body is provided with a gas connecting pipe, the inner port of the gas connecting pipe is communicated with the heating pipeline, and the outer port is used to connect to the heating box; The box body is also provided with a liquid connecting pipe, the inner end of which is connected to the cooling water pipe, and the outer end of which is used to connect to the water cooler; The box body is also provided with a BNC connector, and the heating cylinder in the box body is also provided with a temperature sensor, the temperature sensor is electrically connected to the BNC connector, and the BNC connector is used to connect a temperature measuring instrument; At least one heat dissipation fan is also arranged in the box.

6. The helium-3 neutron polarization device according to claim 5, characterized in that: The box body is composed of a movable cover plate, and a pressure plate sensor is provided on the movable cover plate, and the pressure plate sensor is electrically connected to the controller; A photodiode is also provided at the emission point of the laser, and the photodiode is also electrically connected to the controller; The polarization assembly is also provided with an FID coil and an EPR coil, wherein the FID coil is used to measure the relative polarizability in the polarization cavity, and the EPR coil is used to measure the absolute polarizability; It also includes a mounting tube, a D2 filter and a photodiode, wherein the mounting tube is arranged on the box body, one end of which is aligned with the polarization component, the photodiode is arranged at the other end of the mounting tube, and the D2 filter is arranged in the mounting tube; The cooling water pipe is also provided with a flow switch, and the flow switch is also electrically connected to the controller.

Images