CN111025198A - Ultra-weak magnetic field standard device - Google Patents
Ultra-weak magnetic field standard device Download PDFInfo
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- CN111025198A CN111025198A CN201911191365.6A CN201911191365A CN111025198A CN 111025198 A CN111025198 A CN 111025198A CN 201911191365 A CN201911191365 A CN 201911191365A CN 111025198 A CN111025198 A CN 111025198A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/0017—Means for compensating offset magnetic fields or the magnetic flux to be measured; Means for generating calibration magnetic fields
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Abstract
The invention discloses a very-low-intensity magnetic field standard device, which comprises a three-axis magnetic field coil, a magnetic field noise compensation system, a cryogenic cooling system, a superconducting shielding cylinder and a very-low-intensity magnetic field coil, wherein the three-axis magnetic field coil is connected with the magnetic field noise compensation system; the low-temperature cooling system is arranged in a magnetic field environment constructed by the three-axis magnetic field coil and the magnetic field noise compensation system, the three-axis magnetic field coil compensates the earth magnetic field fixed component, and the magnetic field noise compensation system compensates the earth magnetic field noise; the superconducting shielding cylinder is positioned in the cryogenic cooling system, the cryogenic cooling system realizes the ultralow temperature environment again, the superconducting shielding cylinder reaches below the superconducting critical temperature, the magnetic field shielding is realized in the cylinder, and the extremely-weak magnetic field coil is positioned in the superconducting shielding cylinder to generate an extremely-weak magnetic field. The invention can provide an ultra-low noise 'zero magnetic space' environment for an extremely-weak magnetic field.
Description
Technical Field
The invention belongs to the field of electromagnetic fields, and particularly relates to a weak magnetic field standard device.
Background
The superconducting quantum magnetometer is a magnetometer with the highest sensitivity at present, and is mainly used for Feite magnetic field measurement such as magnetocardiography, magnetoencephalography and rock measurement in ancient geomagnetism, the magnitude value generated by the device researched at present can only reach nano level at the lowest, the stability can only reach Peter level at the lowest, the lowest magnetic field magnitude value and the magnetic field stability are 3 orders of magnitude lower than those of the superconducting quantum magnetometer, and the testing requirement of the superconducting quantum magnetometer can not be met far. Therefore, a device capable of establishing a standard very weak magnetic field environment with magnetic field noise below fT level and magnetic field below pt level is required.
Disclosure of Invention
In view of this, the invention provides a very-low magnetic field standard device, which can provide an ultra-low noise 'zero magnetic space' environment for a very-low magnetic field.
The invention is realized by the following technical scheme:
a kind of very low magnetic field standard device, including three-axis magnetic field coil, magnetic field noise compensating system, cryogenic cooling system, superconductive shielding cylinder and very low magnetic field coil;
the low-temperature cooling system is arranged in a magnetic field environment constructed by the three-axis magnetic field coil and the magnetic field noise compensation system, the three-axis magnetic field coil compensates the earth magnetic field fixed component, and the magnetic field noise compensation system compensates the earth magnetic field noise; the superconducting shielding cylinder is positioned in the cryogenic cooling system, the cryogenic cooling system realizes the ultralow temperature environment again, the superconducting shielding cylinder reaches below the superconducting critical temperature, the magnetic field shielding is realized in the cylinder, and the extremely-weak magnetic field coil is positioned in the superconducting shielding cylinder to generate an extremely-weak magnetic field.
Further, the cryogenic cooling system includes a nonmagnetic dewar and liquid helium contained within the nonmagnetic dewar.
Furthermore, the superconducting shielding cylinder is made of superconducting grade metal niobium, and the RRR value is larger than 300; the superconducting shielding cylinder is a cylinder and is formed by sleeving 2-3 layers of cylinder shells, each layer of cylinder shell comprises a cylinder body and a cylinder cover, the cylinder cover is installed at the upper end of the cylinder shell, wire outlet holes are formed in the cylinder cover, and the length-diameter ratio of each layer of cylinder body is larger than 4.
Further, the diameter of the wire outlet hole is smaller than 1/10 of the diameter of the superconducting shielding cylinder.
Has the advantages that:
1. the invention adopts the three-axis magnetic field coil to compensate the fixed component of the geomagnetic field, adopts the magnetic field noise compensation system to compensate the magnetic field noise, adopts the superconducting shielding cylinder on the basis, utilizes the superconducting material to be in a superconducting state in an ultralow temperature environment, and can completely shield the external magnetic field, thereby realizing the ultralow noise environment of zero magnetic space. Because the internal space of the superconducting shielding cylinder completely shields the external magnetic field and the internal superconducting current is uniformly distributed, the distribution state of the internal space magnetic field is stable, a stable zero-magnetic space environment can be provided for the high-precision superconducting magnetometer, and the superconducting shielding cylinder is a standard device for generating a high-stability fT-level magnetic field. The standard device can test the superconducting quantum magnetometer with the highest stability at present, and compared with the existing standard device, the reproduced magnetic field magnitude and noise are at least 3 orders of magnitude lower.
2. The length-diameter ratio of each layer of the cylinder body of the shielding cylinder is more than 4, so that the magnetic field shielding coefficients of the central area can be ensured to be consistent.
3. The diameter of the wire outlet hole is smaller than 1/10 of the diameter of the superconducting shielding cylinder, so that the external magnetic field interference can be reduced.
Drawings
FIG. 1 is a schematic view of the present invention;
FIG. 2 is a schematic diagram of a cryogenic cooling system, a superconducting shielding cartridge, and a very low field coil;
FIG. 3 is a schematic view of a superconducting shielding cartridge;
the system comprises a three-axis magnetic field coil 1, a magnetic field noise compensation system 2, a cryogenic cooling system 3, a non-magnetic Dewar flask 4, liquid helium 5, a superconducting shielding cylinder 6, a weak magnetic field coil 7, a cylinder body 8, a cylinder cover 9 and an optical pump magnetometer 10.
Detailed Description
The invention is described in detail below by way of example with reference to the accompanying drawings.
The present embodiment provides a very-low-intensity magnetic field standard apparatus, as shown in fig. 1, including a three-axis magnetic field coil 1, a magnetic field noise compensation system 2, a cryogenic cooling system 3, a superconducting shielding cylinder 6, and a very-low-intensity magnetic field coil 7.
The three-axis magnetic field coil 1 is used for compensating the earth magnetic field fixed component, the magnetic field noise compensation system 2 is used for compensating earth magnetic field noise, a stable magnetic field environment is created for the extremely-weak magnetic field coil 7, the magnetic field value after compensation or shielding is less than 50nT, and the magnetic field noise is not more than 10 pT. The magnetic field noise is measured by the optical pump magnetometer 10, and a magnetic field noise measurement reference value is provided.
As shown in fig. 2, the cryogenic cooling system 3 includes a non-magnetic dewar 4 and liquid helium 5, the non-magnetic dewar 4 is filled with the liquid helium 5, and the cryogenic temperature of the cryogenic cooling system 3 reaches 4.2 k. The superconducting shielding cylinder 6 is immersed in the liquid helium 5, the liquid helium 5 cools the superconducting shielding cylinder 6 to below the critical temperature, a 4.2k temperature space is established, the superconducting shielding cylinder 6 is in a superconducting state, the superconducting shielding cylinder 6 realizes magnetic field shielding under the action of the Meissner effect, an ultralow-noise zero magnetic field space is established, and an fT-level zero magnetic field space is generated. The weak magnetic field coil 7 can generate a high-precision weak magnetic field, and can be used for testing a high-precision superconducting magnetometer such as the optical pump magnetometer 10. The extremely weak magnetic field means that the magnetic field intensity reaches the pT level or below.
The superconducting shielding cylinder 6 is prepared from superconducting grade niobium with the purity of 99.999 percent and the RRR value of more than 300. The superconducting shielding cylinder 6 is a cylinder and is formed by sleeving 2-3 layers of cylindrical shells, and the thickness of each layer is not less than 1 mm. As shown in fig. 3, each layer of cylindrical shell comprises a cylinder body 8 and a cylinder cover 9, the cylinder cover 9 is installed at the upper end of the cylindrical shell, a wire outlet hole is formed in the cylinder cover 9, the diameter of the wire outlet hole is smaller than 1/10 of the diameter of the superconducting shielding cylinder 6, and the length-diameter ratio of each layer of cylinder body 8 is larger than 4. The cylinder 8 can be formed by welding a bottom cover through vacuum electron beam welding by a cylindrical shell, and can also be of an integrated structure. After welding, the surface must be polished to ensure the surface to be flat and smooth, and the surface of the prepared superconducting shielding cylinder 6 is subjected to acid cleaning treatment to remove an oxide layer.
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (4)
1. A very low magnetic field standard device is characterized by comprising a three-axis magnetic field coil, a magnetic field noise compensation system, a cryogenic cooling system, a superconducting shielding cylinder and a very low magnetic field coil;
the low-temperature cooling system is arranged in a magnetic field environment constructed by the three-axis magnetic field coil and the magnetic field noise compensation system, the three-axis magnetic field coil compensates the earth magnetic field fixed component, and the magnetic field noise compensation system compensates the earth magnetic field noise; the superconducting shielding cylinder is positioned in the cryogenic cooling system, the cryogenic cooling system realizes the ultralow temperature environment again, the superconducting shielding cylinder reaches below the superconducting critical temperature, the magnetic field shielding is realized in the cylinder, and the extremely-weak magnetic field coil is positioned in the superconducting shielding cylinder to generate an extremely-weak magnetic field.
2. The very low field magnetic standard apparatus of claim 1, wherein the cryogenic cooling system comprises a nonmagnetic dewar and liquid helium contained within the nonmagnetic dewar.
3. The low-intensity magnetic field standard apparatus of claim 1, wherein the superconducting shielding cylinder is made of superconducting grade niobium metal, and the RRR value is greater than 300; the superconducting shielding cylinder is a cylinder and is formed by sleeving 2-3 layers of cylinder shells, each layer of cylinder shell comprises a cylinder body and a cylinder cover, the cylinder cover is installed at the upper end of the cylinder shell, wire outlet holes are formed in the cylinder cover, and the length-diameter ratio of each layer of cylinder body is larger than 4.
4. The weak magnetic field standard apparatus of claim 3, wherein the diameter of the outlet hole is smaller than 1/10 of the diameter of the superconducting shielding cylinder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201911191365.6A CN111025198A (en) | 2019-11-28 | 2019-11-28 | Ultra-weak magnetic field standard device |
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| CN201911191365.6A CN111025198A (en) | 2019-11-28 | 2019-11-28 | Ultra-weak magnetic field standard device |
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Citations (11)
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| JPH01245598A (en) * | 1988-03-28 | 1989-09-29 | Japan Atom Energy Res Inst | High temperature superconductor zero magnetic field standard device |
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| CN105206375A (en) * | 2015-09-22 | 2015-12-30 | 安徽万瑞冷电科技有限公司 | Actively-shielding type experiment device of low-temperature superconducting magnet system |
| CN205643747U (en) * | 2016-05-11 | 2016-10-12 | 北京斯奎德量子技术有限公司 | Calibration arrangement for ware intrinsic noise is interfered to superconductive quantum |
| CN109188318A (en) * | 2018-09-14 | 2019-01-11 | 北京航空航天大学 | A kind of integrated low noise magnetic screen of SERF magnetic field measuring device and magnetic compensation device |
| CN109298357A (en) * | 2018-09-07 | 2019-02-01 | 中国科学院上海微系统与信息技术研究所 | Vector Magnetic Field systems stabilisation based on SQUID three axis magnetometer |
| CN109765505A (en) * | 2018-12-29 | 2019-05-17 | 中国船舶重工集团公司第七一0研究所 | A kind of magnetic field compensation apparatus |
| CN109765506A (en) * | 2018-12-29 | 2019-05-17 | 中国船舶重工集团公司第七一0研究所 | A kind of screening arrangement internal magnetic field noise compensation apparatus |
| CN209641460U (en) * | 2019-04-24 | 2019-11-15 | 中国航天科工飞航技术研究院（中国航天海鹰机电技术研究院） | Superconducting magnet with electromagnetic protection component |
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2019
- 2019-11-28 CN CN201911191365.6A patent/CN111025198A/en active Pending
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01245598A (en) * | 1988-03-28 | 1989-09-29 | Japan Atom Energy Res Inst | High temperature superconductor zero magnetic field standard device |
| CN102997037A (en) * | 2011-09-19 | 2013-03-27 | 北京云电英纳超导电缆有限公司 | Dewar with magnetic shielding or electromagnetic shielding |
| CN203616458U (en) * | 2013-11-15 | 2014-05-28 | 中国船舶重工集团公司第七一〇研究所 | Magnetic field repetition measurement noise compensation device |
| CN104330754A (en) * | 2014-09-29 | 2015-02-04 | 北京美尔斯通科技发展股份有限公司 | Superconducting weak magnetic signal detection magnetometer |
| CN105206375A (en) * | 2015-09-22 | 2015-12-30 | 安徽万瑞冷电科技有限公司 | Actively-shielding type experiment device of low-temperature superconducting magnet system |
| CN205643747U (en) * | 2016-05-11 | 2016-10-12 | 北京斯奎德量子技术有限公司 | Calibration arrangement for ware intrinsic noise is interfered to superconductive quantum |
| CN109298357A (en) * | 2018-09-07 | 2019-02-01 | 中国科学院上海微系统与信息技术研究所 | Vector Magnetic Field systems stabilisation based on SQUID three axis magnetometer |
| CN109188318A (en) * | 2018-09-14 | 2019-01-11 | 北京航空航天大学 | A kind of integrated low noise magnetic screen of SERF magnetic field measuring device and magnetic compensation device |
| CN109765505A (en) * | 2018-12-29 | 2019-05-17 | 中国船舶重工集团公司第七一0研究所 | A kind of magnetic field compensation apparatus |
| CN109765506A (en) * | 2018-12-29 | 2019-05-17 | 中国船舶重工集团公司第七一0研究所 | A kind of screening arrangement internal magnetic field noise compensation apparatus |
| CN209641460U (en) * | 2019-04-24 | 2019-11-15 | 中国航天科工飞航技术研究院（中国航天海鹰机电技术研究院） | Superconducting magnet with electromagnetic protection component |
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Application publication date: 20200417 |