Compact solid-state isotope separation device based on small-angle scattering and charge exchange

Abstract

The invention discloses a compact solid-state isotope separation device based on small-angle scattering and charge exchange, relates to the technical field of isotope separation devices, and comprises a laser ablation atomic source, an optical molasses collimation module, a laser action module, and a magnet scattering and resonance ionization coupling module; the laser ablation atomic source prepares a ground state isotope atomic beam, which is subjected to transverse laser cooling to achieve a collimation effect; the laser action module optically pumps isotope atoms to be separated to a strong field or weak field state-seeking state, and the remaining isotope atoms are optically pumped to a weak field or strong field state-seeking state; the optically pumped atomic beam is scattered at a small angle with the surface of a magnet, the isotope atoms in the strong field state-seeking state are attracted by magnetic force and adhere to the surface of the magnet, and the isotope atoms in the weak field state-seeking state are away from the magnet, and a voltage is applied on a voltage plate to ensure the collection of charged particles after the charge exchange, thereby completing the separation of isotopes; the invention greatly improves the separation capability of solid-state isotopes, and reduces the volume, weight and power consumption of the device.

Description

Technical Field

[0001] The invention relates to the technical field of isotope separation devices, and in particular to a compact solid-state isotope separation device based on small-angle scattering and charge exchange. Background Art

[0002] In the periodic table, elements with the same atomic number but different numbers of neutrons are called isotopes. Since isotopes were first discovered in the 20th century, various types of isotopes have been widely used in basic research, physics, medicine, earth science, materials, nuclear industry and other fields.

[0003] From the discovery of isotopes to the present, people have adopted many methods to separate isotopes. These methods are mainly divided into chemical methods and physical methods. Commonly used physical methods include diffusion method, electromagnetic method, centrifugal method and laser separation method. In recent years, the research on isotope separation using low-power laser has made great progress. The atomic vapor laser isotope separation method is recognized as an advanced separation method that uses laser to replace gas diffusion process, centrifugal separation process and electromagnetic separation process.

[0004] Taking patent CN1032790C as an example, a polarized beam magnetic deflection laser isotope enrichment device is disclosed. The device allows an atomic beam to interact with a vertically incident laser beam in a weak oriented magnetic field, so that atoms of different isotopes are selectively optically pumped to form atomic beams polarized in different directions. After passing through a selective magnet, unnecessary isotopes are deflected, and necessary ones are focused and collected.

[0005] However, the isotope enrichment device has the following shortcomings: (1) The device uses a resistive-heating atomic furnace. The atomic flux generated by this type of heating atomic furnace is continuous and cannot be quickly shut down. Therefore, it is inevitable that excess evaporated atoms will be generated, resulting in a waste of raw materials. In addition, when the melting point temperature of the isotope element to be separated is as high as thousands of degrees Celsius, the heating atomic furnace of the device is difficult to meet the technical requirements. (2) In this device, the current required to heat an atomic furnace to a typical temperature of several hundred degrees Celsius will affect the magnetic field in the nearby laser action area. (3) The device uses a collimating aperture to collimate the atomic beam, which will reduce the flux of the atomic beam and cause waste of raw materials; (4) The device adopts a quadrupole or sextuple magnet design with high magnetic field strength, which has a large volume and energy consumption; (5) In this device, the pole holes of the multipole magnet are small and the center is a non-magnetic area. The atomic beam cannot be completely deflected by the magnetic force. Only the isotope atoms at the edge of the beam can be focused or diverged by the magnetic force, resulting in low separation efficiency and low yield, which is not conducive to the separation and enrichment of isotopes and limits its industrial application.

[0006] Therefore, the present invention provides a compact solid-state isotope separation device based on small-angle scattering and charge exchange to solve the above technical problems. Summary of the invention

[0007] The present invention overcomes the deficiencies of the prior art and provides a compact solid isotope separation device based on small-angle scattering and charge exchange with high separation efficiency, small size and low power consumption.

[0008] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0009] A compact solid-state isotope separation device based on small-angle scattering and charge exchange, comprising a laser ablation atomic source, an optical molasses collimation module, a laser action module, a magnet scattering and resonance ionization coupling module; wherein;

[0010] The laser ablation atomic source includes an atomic chamber and a heating laser system. The atomic chamber is a cavity structure with a light hole, in which an isotope is placed. The laser adjusted to a certain energy density is focused on the isotope through the light hole, and the surface is ablated to produce a ground state atomic beam.

[0011] Preferably, a special structure can be loaded and unloaded inside the atomic chamber to provide preliminary collimation for the atomic beam; the special structure includes: an array pinhole structure, a tubular structure, a slit structure, and a mesh structure.

[0012] The optical molasses collimation module includes an ultra-high vacuum all-glass chamber, a collimation laser system, and a set of reflector arrays, which can slow down the lateral velocity of atoms to achieve the collimation effect. The ultra-high vacuum all-glass chamber is connected to the front-end atomic chamber and the rear-end laser vacuum chamber.

[0013] Preferably, the frequency of the laser provided by the collimated laser system is slightly lower than the optical resonance frequency of the isotope atoms to be separated. After being expanded into a suitable spot size, the laser is emitted to the ultra-high vacuum all-glass chamber at a certain angle, and then reflected back and forth by the reflector array, so that the spot covers the entire ultra-high vacuum all-glass chamber as much as possible;

[0014] Preferably, the reflector array is arranged in such a way that the incident angle of the laser on the reflector gradually increases until it approaches 90°.

[0015] The laser action module includes a laser vacuum chamber, a pump laser system, and a magnetic field; glass windows are set on both sides of the laser vacuum chamber, and the laser vacuum chamber is used for the interaction between the laser and the isotope atomic beam; the pump laser system contains multiple laser beams with wavelengths corresponding to the selective excitation of different isotopes, and they are merged into one beam of light; in the laser action module, the direction of the magnetic field is the direction of the quantization axis of the atom, and the laser is perpendicular to the atomic beam, which can simultaneously optically pump the isotope atoms to be separated to the strong field search state (weak field search state), and optically pump the remaining isotope atoms to the weak field search state (strong field search state).

[0016] The magnet scattering and resonance ionization coupling module includes a high vacuum chamber, a high gradient magnet, a voltage system, and a precise positioning, detection, and collection system.

[0017] Preferably, the high gradient magnet is a regularly arranged high magnetic field gradient magnet installed at the bottom of the vacuum chamber. Within 1.5 mm around the magnet, the magnetic field gradient is greater than that of a traditional Halbach array magnet of the same volume, and the magnetic field gradient is >3T / cm.

[0018] Preferably, the voltage system includes a voltage plate and a power supply. The voltage plate is fixed at the bottom of the rectangular vacuum chamber and located in front of the magnet, and is electrically insulated from the chamber. The power supply provides it with a positive voltage to repel and collect positive ions that are resonantly ionized when scattered from the magnet surface on its surface.

[0019] Since the present invention uses a laser ablation atomic source, an optical molasses collimation module, a magnet with a larger magnetic field gradient, and a voltage system combined with the principle of resonant ionization, the volume, weight and power consumption of the device are greatly reduced, and the separation capacity is greatly improved compared with traditional devices. Compared with the traditional polarized beam magnetic deflection isotope separation device, the beneficial effects of the present invention are as follows:

[0020] 1. The use of laser ablation atomic source, compared with the heating atomic furnace in the traditional polarized beam magnetic deflection isotope separation device, can directly and controllably produce a large number of gaseous ground-state atoms, avoiding the waste of raw materials in the heating and cooling process of the traditional heating atomic furnace; it can avoid the interference of the heating current of the heating atomic furnace in the traditional separation device on the magnetic field near the laser action area; it can avoid the use of supporting equipment of the heating atomic furnace in the traditional separation device (such as heating wire, power supply, insulation layer, temperature controller, vacuum valve, etc.), greatly reducing the size and energy consumption of the device.

[0021] 2. By adopting the laser ablation atomic source, this separation device can meet the separation requirements of isotope elements with melting points as high as thousands of degrees Celsius. The atomic furnace in the traditional separation device, when heated to a high temperature of thousands of degrees Celsius, will have strict requirements on the material, heating power, thermal insulation performance, temperature detection, etc. of the atomic furnace. Therefore, this separation device can separate a wider range of solid isotopes than traditional separation devices.

[0022] 3. The optical molasses collimation module is used to collimate the atomic beam using laser cooling. Compared with the aperture collimation method in the traditional separation device, it can reduce the divergence of the beam, avoid the reduction of beam flux, reduce the waste of isotopes, and greatly improve the isotope separation efficiency.

[0023] 4. The high-gradient magnet used in the separation device can avoid the non-magnetic area in the center of the quadrupole or sextupole magnet in the traditional separation device, so that the atomic beam can be fully affected by the magnetic force. In addition, the high-gradient magnet in the separation device has a magnetic field gradient within 1.5 mm near the magnet that is much greater than that of the traditional Halbach array magnet of the same volume, and the separation efficiency is higher. Therefore, the length of the magnet in the device of the present invention can be greatly reduced, thereby greatly reducing the volume, weight and power consumption of the device, reducing costs, and being more conducive to industrial applications.

[0024] 5. This separation device adds a new type of resonant ionization device. When atoms scatter with the magnet surface, they undergo resonant ionization. This device adds the required voltage to the magnetic field action area. These resonantly ionized ions are collected by the voltage plate to avoid mixing with the separated atoms, thereby improving the separation coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0026] Figure 2 yes Figure 1 Schematic diagram of the structure of a high gradient magnet;

[0027] Figure 3 yes Figure 1 Schematic diagram of the magnetization direction of a high gradient magnet;

[0028] Figure 4 yes Figure 1 Simulation comparison of magnetic field strength between high gradient magnet and traditional Halbach magnet array;

[0029] Figure 5 yes Figure 1 Simulation comparison of magnetic field gradients of high-gradient magnets and traditional Halbach magnet arrays;

[0030] Figure 6 yes Figure 1 Schematic diagram of the voltage board structure.

[0031] Figure numerals: 1. Laser ablation atomic source; 2. Atomic chamber; 3. Heating laser system; 4. Special structure that can provide preliminary collimation; 5. Optical molasses collimation module; 6. Ultra-high vacuum all-glass chamber; 7. Collimation laser system; 8. Mirror array; 9. Laser action module; 10. Laser vacuum chamber; 11. Pump laser system; 12. Magnetic field; 13. Magnet scattering and resonance ionization coupling module; 14. High gradient magnet; 15. Voltage plate; 1501. Power connection; 1502. Ceramic insulating bracket; 16. Detection and collection system. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to these embodiments.

[0033] Example 1

[0034] Figure 1-6 The present invention relates to a compact solid-state isotope separation device based on small-angle scattering and charge exchange, comprising a laser ablation atomic source 1, an optical molasses collimation module 5, a laser action module 9, and a magnet scattering and resonance ionization coupling module 13.

[0035] The laser ablation atomic source 1 comprises an atomic chamber 2 and a heating laser system 3. The atomic chamber is a cavity structure with a light hole, in which an isotope is placed. The laser adjusted to a certain energy density is focused on the isotope through the light hole to ablate the surface to produce a ground state atomic beam. A special structure 4 is installed inside the atomic chamber to provide preliminary collimation.

[0036] The optical molasses collimation module 5 comprises an ultra-high vacuum all-glass chamber 6, a collimation laser system 7, a reflector array 8, and a vacuum acquisition and measurement system. The ultra-high vacuum all-glass chamber 6 is connected to the front-end atomic chamber 2 and the rear-end laser vacuum chamber 10. The frequency of the laser provided by the collimation laser system 7 is slightly lower than the optical resonance frequency of the isotope atoms to be separated. After the laser is expanded into a suitable spot size, it is emitted to the ultra-high vacuum all-glass chamber 6 at a certain angle, and then reflected back and forth by the reflector array 8, so that the spot covers the entire ultra-high vacuum all-glass chamber 6 as much as possible. When the atomic beam passes through this area, it is subjected to transverse laser cooling to achieve the collimation effect.

[0037] The laser action module 9 includes a laser vacuum chamber 10, a pump laser system 11, and a magnetic field 12. Glass windows are arranged on both sides of the laser vacuum chamber 10. The laser vacuum chamber 10 is used for the interaction between the laser and the isotope atomic beam. The pump laser system 11 includes multiple laser beams of wavelengths corresponding to selective excitation of different isotopes, which are merged into one beam of light. In the laser action module 9, there is a magnetic field 12 provided by a Helmholtz coil. The direction of the magnetic field is the direction of the quantized axis of the atom. The laser is perpendicular to the atomic beam, and can simultaneously optically pump the isotope atoms to be separated to the strong field seeking state (weak field seeking state), and optically pump the remaining isotope atoms to the weak field seeking state (strong field seeking state).

[0038] The magnet scattering and resonance ionization coupling module 13 includes a high vacuum chamber, precision positioning, a high gradient magnet 14, a voltage plate 15, and a detection and collection system 16. The high gradient magnet 14 is a high magnetic field gradient magnet arranged in a regular pattern (such as Figure 2 As shown), it is installed at the bottom of the vacuum chamber. Within 1.5㎜ around the magnet, the magnetic field gradient is greater than that of the traditional Halbach array magnet of the same volume, and the magnetic field gradient is >3T / ㎝ (as shown Figure 5As shown), the voltage plate 15 is fixed at the bottom of the rectangular vacuum chamber and is located in front of the high gradient magnet 14 (structure as shown Figure 6 As shown), the required bias voltage is provided for collecting ions that undergo resonant ionization when scattered on the magnet surface. Finally, the separated isotope atomic beam is detected and collected by the detection and collection system 16.

[0039] The application of the present invention in separating boron isotopes is specifically demonstrated below.

[0040] In this embodiment, the diameter of the atomic chamber 2 is 16 mm, the length is 100 mm, and about 2 g of boron isotopes are placed inside. The laser output power in the heating laser system 3 can reach 7 W. The laser is focused on the boron isotope target through the light hole, and the surface is ablated to produce a ground state atomic beam. A stainless steel plate with an array pinhole structure is installed inside the atomic chamber for preliminary collimation of the atomic beam.

[0041] The boron atom beam passes through the ultra-high vacuum all-glass chamber 6, which is an ultra-high vacuum chamber made of ultraviolet fused quartz with a length of 18 cm. Both sides of the light passage are coated with anti-reflection films to reduce the loss of light intensity. The deep ultraviolet laser provided by the collimated laser system 7 has a central wavelength of 249.7 nm. After being expanded into an elliptical spot of about 15 mm × 8 mm, the laser is emitted to the ultra-high vacuum all-glass chamber 6 at an angle of about 3° from the vertical direction, and then reflected back and forth 12 times by the reflector array 8. The length of the spot coverage area can reach 17 cm. When the atomic beam passes through this area, it is subjected to transverse laser cooling to achieve the collimation effect.

[0042] When the collimated boron atom beam passes through the laser vacuum chamber 10, boron-10 and boron 11 are pumped by laser light to the strong field state and weak field state, respectively. The laser vacuum chamber is a vacuum chamber with a six-way CF flange and glass windows on both sides for vertical interaction between the laser and the lithium atom beam. Outside the laser vacuum chamber 10, a three-dimensional square Helmholtz coil is used to compensate for the earth's magnetic field and generate a single magnetic field in the direction of the atomic quantization axis. In this embodiment, the pump laser system 11 provides σ-polarized lasers with central wavelengths of 249.677nm and 249.771nm, and the boron-10 atoms are eventually optically pumped to 2 P 1 / 2 , F=5 / 2 state and 2 P 3 / 2 , F=3 / 2 state; the boron-11 atom is finally optically pumped to 2 P 1 / 2 , F=2 state and 2 P 3 / 2 state.

[0043] The atomic beam after optical pumping enters the ultra-high vacuum chamber, in which a high-gradient magnet 14 is installed. The rectangular vacuum chamber is softly connected to the laser vacuum chamber 10 in front, and the central axes of the two form a small angle through a precision motion slider, so that the boron isotope atoms selectively excited by the laser scatter at a small angle on the magnet surface. A voltage plate 15 is fixed in front of the high-gradient magnet 14, and the structure is as follows Figure 6 As shown, one end of the DC power supply is connected to the voltage plate to apply a bias voltage, and the other end is connected to the side wall of the vacuum chamber and is set to a ground state. The voltage plate 15 is placed in a ceramic insulating bracket and fixed to the bottom of the ultra-high vacuum chamber through a base. The voltage plate 15 can adjust the required bias voltage.

[0044] In this embodiment, the high gradient magnet 14 is as follows Figure 2 , Figure 3 The long strip magnet array composed of the magnet configuration shown in the figure has a total length of 86.4 cm. Through simulation with COMSOL Multiphysics simulation software, it is found that the magnetic field gradient of the high gradient magnet 14 of the embodiment of the present invention is greater than the magnetic field gradient of the traditional Halbach array magnet of the same volume near the magnet surface 1.5 mm, as shown in FIG. Figure 5 As shown. Atoms with a certain magnetic moment feel magnetic force. Boron-11 atoms scattered by magnetic force fly away from the surface of the magnet, while boron-10 atoms attracted by magnetic force adhere to the surface of the magnet. Some non-adherent boron-10 atoms scatter with the magnet surface and undergo resonance ionization, which may become positive ions. The voltage of the voltage plate 15 is adjusted to collect these ions to avoid mixing with the separated boron-11 atoms, thereby completing the isotope separation of boron-10 and boron-11. For other isotopes, particularly lithium isotope atoms, it is easier to scatter with the magnet to form positive ions and mix with the separated atoms, resulting in the lithium isotope separation coefficient being unable to be improved. The current voltage plate module can solve this technical problem well and improve the isotope separation coefficient.

[0045] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A compact solid-state isotope separation device based on small-angle scattering and charge exchange, characterized in that: The invention comprises a laser ablation atomic source (1), an optical molasses collimation module (5), a laser action module (9), and a magnet scattering and resonant ionization coupling module (13); the laser ablation atomic source (1) comprises an atomic chamber (2) and a heating laser system (3); the atomic chamber (2) is a cavity structure with a light-through hole, in which an isotope single substance is placed, and a laser adjusted to a certain energy density is focused on the isotope single substance through the light-through hole, and a ground state atomic beam is generated by ablating the surface; a special structure (4) capable of providing preliminary collimation is installed inside the atomic chamber (2), providing preliminary collimation for the atomic beam; the optical molasses collimation module (5) comprises an ultra-high vacuum all-glass chamber (6), a collimation laser system (7), and a group of reflector arrays (8), which can decelerate the lateral velocity of atoms to achieve a collimation effect; the frequency of the laser provided by the collimation laser system (7) is slightly lower than the optical frequency of the isotope atoms to be separated. The laser beam is expanded into a suitable spot size and then emitted at a certain angle to an ultra-high vacuum all-glass chamber (6), and then reflected back and forth by a reflector array (8), so that the spot covers the entire ultra-high vacuum all-glass chamber (6) as much as possible; the reflector array (8) is arranged in such a way that the incident angle of the laser beam on the reflector gradually increases until it is close to 90°; the magnet scattering and resonance ionization coupling module (13) comprises a high-gradient magnet (14) and a voltage system; the high-gradient magnet (14) is a regularly arranged high-magnetic field gradient magnet installed at the bottom of the vacuum chamber, and within a range of 1.5 mm near the magnet, the magnetic field gradient is greater than 3T / cm; the voltage system comprises a voltage plate (15) and a power supply, the voltage plate (15) being fixed at the bottom of the rectangular vacuum chamber and located in front of the magnet, and being used to collect ions that undergo resonance ionization when scattered from the magnet surface and provide the required bias voltage.

2. The compact solid-state isotope separation device based on small-angle scattering and charge exchange according to claim 1, characterized in that: The special structure (4) that can provide preliminary collimation includes an array pinhole structure, a tubular structure, a slit structure, and a mesh structure.

3. The compact solid-state isotope separation device based on small-angle scattering and charge exchange according to claim 1, characterized in that: The laser action module (9) comprises a laser vacuum chamber (10), a pump laser system (11), and a magnetic field (12); the laser action module (9) can simultaneously optically pump the isotope atoms to be separated to a strong field search state, and optically pump the remaining isotope atoms to a weak field search state; conversely, the laser action module (9) can simultaneously optically pump the isotope atoms to be separated to a weak field search state, and optically pump the remaining isotope atoms to a strong field search state.

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