CN116148727A - Multi-detection mode magnetic field compensation device, magnetic field compensation method and magnetic shielding system - Google Patents
Multi-detection mode magnetic field compensation device, magnetic field compensation method and magnetic shielding system Download PDFInfo
- Publication number
- CN116148727A CN116148727A CN202111373386.7A CN202111373386A CN116148727A CN 116148727 A CN116148727 A CN 116148727A CN 202111373386 A CN202111373386 A CN 202111373386A CN 116148727 A CN116148727 A CN 116148727A
- Authority
- CN
- China
- Prior art keywords
- magnetic field
- magnetic
- detector
- working area
- compensation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/02—General constructional details
- G01R1/18—Screening arrangements against electric or magnetic fields, e.g. against earth's field
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Measuring Magnetic Variables (AREA)
Abstract
The invention relates to a multi-detection mode magnetic field compensation device, a magnetic field compensation method and a magnetic shielding system, wherein the magnetic field compensation method comprises the following steps: detecting the magnetic field intensity in a working area of a magnetic shielding chamber through a first magnetic detector, and comparing the magnetic field intensity in the working area with a first threshold value; when the magnetic field in the working area is larger than a first threshold value, performing first magnetic field compensation operation, and reducing the magnetic field intensity in the working area to a first magnetic field state smaller than or equal to the first threshold value; detecting the magnetic field intensity in the working area through a second magnetic detector when the magnetic field is in the first magnetic field state, and comparing the magnetic field intensity in the working area with a second threshold value; and when the magnetic field intensity in the working area is larger than a second threshold value, performing a second magnetic field compensation operation to reduce the magnetic field intensity in the working area to a second magnetic field state, wherein the range of the second magnetic field state is smaller than that of the first magnetic field state.
Description
Technical Field
The invention relates to a multi-detection mode magnetic field compensation device, a magnetic field compensation method and a magnetic shielding system.
Background
In recent years, with the development of an optically pumped atomic detection technology, research for realizing ultra-high-sensitivity magnetic field measurement based on precession of an atomic spin in a SERF state has been attracting attention. The method can greatly exceed the sensitivity realized by the prior related measurement means, so that a new tool for realizing the world is obtained for human beings. The atomic magnetometer (namely, the atomic magnetic detector) based on the optical pump detection technology can work in room temperature environment, does not need liquid helium cooling, has small volume and light weight, can realize low-cost mass production through a semiconductor process, and brings new dawn for weak magnetic detection of a magnetoencephalography, a magnetocardiography and other medical, biological and material fields.
However, current optical pump atomic magnetometers based on the SERF effect require extremely low background magnetic fields (typically <20 nT) to reach their ideal operating conditions, and have a low dynamic range, so that an active shielding system needs to be introduced to achieve a good magnetic shielding operating environment, achieving extremely low static and gradient fields. The core of the active shielding system is the accurate measurement and active compensation of a magnetic field, and different magnetic detectors cannot be considered in terms of performance parameters such as detection precision, local noise, dynamic range, measurement bandwidth, offset value, temperature drift and the like based on different working principles or setting parameters, so that the application range and performance of the whole system are limited.
Disclosure of Invention
In order to solve the above-mentioned problems and needs, the present invention proposes a technical solution for magnetic field measurement and compensation by using a plurality of magnetic detectors to cooperate, which solves the above-mentioned problems and brings about other technical effects due to the following technical features.
In one aspect, the present invention provides a multi-detection mode magnetic field compensation method, including: determining a first threshold and a second threshold size, the second threshold being smaller than the first threshold; detecting the magnetic field intensity in a working area of a magnetic shielding chamber through a first magnetic detector, and comparing the magnetic field intensity in the working area with a first threshold value; when the magnetic field in the working area is larger than a first threshold value, performing first magnetic field compensation operation, and reducing the magnetic field intensity in the working area to a first magnetic field state smaller than or equal to the first threshold value; detecting the magnetic field intensity in the working area through a second magnetic detector when the magnetic field is in the first magnetic field state, and comparing the magnetic field intensity in the working area with a second threshold value; and when the magnetic field intensity in the working area is larger than a second threshold value, performing a second magnetic field compensation operation to reduce the magnetic field intensity in the working area to a second magnetic field state, wherein the range of the second magnetic field state is smaller than that of the first magnetic field state.
In another aspect, the present invention provides a multi-detection mode magnetic field compensation device, comprising: a magnetic field generator for generating a compensation magnetic field in a working area of the magnetic shielding chamber; a magnetic field detection device for detecting the magnetic field intensity in the working area; a control system that receives a signal indicative of the magnitude of the magnetic field strength detected by the magnetic field detection device; and a driving device for applying a driving signal to the magnetic field generator under the control of the control system to reduce the magnetic field intensity in the working area to a predetermined range, wherein the magnetic field detection device comprises a first magnetic detector and a second magnetic detector, and the detection range of the first magnetic detector is larger than that of the second magnetic detector
In yet another aspect, the present invention provides a magnetic shielding system comprising a magnetic field compensation device as described above.
Drawings
In order to more clearly illustrate the technical solution of the embodiments of the present invention, the following description will briefly explain the drawings of the embodiments of the present invention. Wherein the showings are for the purpose of illustrating some embodiments of the invention only and not for the purpose of limiting the same.
FIG. 1 shows a schematic diagram of a magnetic field compensation device according to an embodiment of the invention;
FIG. 2 shows a perspective view of a magnetic shielding system including a magnetic field compensation device according to an embodiment of the present invention; and
fig. 3 shows a flow chart of a magnetic field compensation method according to an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the technical solutions of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of specific embodiments of the present invention. Like reference numerals in the drawings denote like parts. It should be noted that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be made by a person skilled in the art without creative efforts, based on the described embodiments of the present invention fall within the protection scope of the present invention.
Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The terms "first," "second," and the like in the description and in the claims, are not used for any order, quantity, or importance, but are used for distinguishing between different elements. Likewise, the terms "a" or "an" and the like do not necessarily denote a limitation of quantity. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the listed elements or items following the word and equivalents thereof without precluding other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.
In the following description and the appended claims, the directional terms "inner" and "outer" are used, wherein inner, inner side, inner surface refers to the surface facing the working area surrounded by the magnetic shielding system, and outer, outer side, outer surface refers to the surface opposite to said inner, inner side, inner surface.
The magnetic shielding system commonly used at present usually adopts a magnetic shielding material layer with high magnetic permeability to shield an external magnetic field, but only a passive shielding material is difficult to well eliminate residual magnetic fields and gradient fields in a shielding room and residual magnetic field fluctuation caused by external magnetic field change under the limitations of cost, volume and weight, and a sensitive magnetic detector sensitive to a static magnetic field is difficult to directly achieve optimal performance in the common magnetic shielding system.
In order to provide an optimized working environment for a sensitive magnetic detector, it is often necessary to provide a better working environment for the magnetic detector by measuring the magnetic field and based on the measured data, to actively compensate the magnetic field for part or all of the area within the shielding system.
Active magnetic field measurement and compensation devices require a magnetic detector to measure the magnetic field in the compensation zone and to compensate by the magnetic field compensation device. The magnetic field compensation device, typically a coil or other type of magnetic field generator, can be controlled by controlling its input current to generate a magnetic field of a particular spatial distribution, thereby compensating for static, varying and gradient fields within the target region. In general, different types of magnetic detectors have different performance parameters, and it is difficult to simultaneously meet the requirements of high dynamic range, high measurement accuracy, high working bandwidth, low cost and the like for realizing high-performance active magnetic field measurement and compensation.
Taking the SERF effect atomic magnetometer as an example, the SERF effect atomic magnetometer has the characteristics of high sensitivity and low noise, but has low dynamic range, needs a low magnetostatic environment and has narrow working bandwidth, so that the SERF effect atomic magnetometer is difficult to directly use as a magnetic detector of an active magnetic field measurement-compensation device in an unshielded environment and a part of low-performance shielded environment.
The giant magnetoresistance (giant magnetoresistance, GMR) is a magnetic sensor, has lower sensitivity and higher noise level than the SERF effect atomic magnetometer, but has a large dynamic range, can work in an unshielded geomagnetic field environment, has a wide working frequency band, and can effectively detect magnetic field changes in a higher frequency range. In addition to GMR, flux gates, hall effect devices, diamond hole magnetometers, and other sensors that operate in the presence of a larger magnetic field may also achieve the same or similar effects, and thus may be alternatively selected according to actual needs.
In an environment with a higher static magnetic field, the SERF effect atomic magnetometer cannot enter a working state so as to effectively detect the magnetic field intensity and distribution in a region to be shielded; while magnetic sensors such as GMR's are effective in detecting magnetic field strength and distribution in such environments, their low sensitivity and high noise levels limit the performance of active compensation devices.
Aiming at the problems, the invention provides a magnetic field active measurement-compensation device, which realizes a plurality of detection modes by a plurality of detectors working cooperatively in a certain method, and the technical scheme of the invention can realize high-performance measurement and compensation of static magnetic fields, changing magnetic fields and magnetic field gradients in a certain space range so as to provide a good working environment for sensitive magnetic detectors in a passive magnetic shielding system or an open environment or provide an active shielding system with higher performance.
Exemplary embodiments of the present invention will be described more fully hereinafter with reference to the accompanying drawings. Possible embodiments within the scope of the invention may have fewer components, have other components not shown in the drawings, different components, differently arranged components or differently connected components, etc. than the examples shown in the drawings. Furthermore, two or more of the elements in the figures may be implemented in a single element or the single element shown in the figures may be implemented as multiple separate elements without departing from the concepts of the present invention.
Fig. 1 shows a schematic diagram of a magnetic field compensation device according to an embodiment of the invention. Fig. 2 shows a perspective view of a magnetic shielding system comprising a magnetic field compensation device according to an embodiment of the invention.
The multi-detection mode magnetic field compensation device according to one embodiment of the present invention, as shown in fig. 1, includes a first magnetic detector 1, a second magnetic detector 2, a magnetic field generator 3, a control system 4, and a driving device 5.
The magnetic field generator 3 is used to generate a compensating magnetic field in the working area 6 of the magnetic shielding chamber. The magnetic field generating means 3 may be a coil, for example. For example, in the present embodiment, the magnetic field generating device 3 is a coil circuit constituted by an exciting coil, the coil is arranged on a magnetic shielding material layer of a magnetic shielding room, and forms a closed magnetic circuit with the magnetic shielding room, and a space compensation magnetic field can be generated when energized. The coils can be arranged not only on the edges of the magnetic shielding chamber, but also on the surfaces of the magnetic shielding chamber, and the magnetic field distribution on the surfaces of the magnetic shielding chamber in the demagnetizing process is as uniform as possible through specific coil arrangement and winding number selection.
It should be noted that, the "working area" as used herein refers to an area where the magnetic detection system is located, and a subject or a sample to be measured (collectively referred to as a "target object") is accommodated in the working area when the magnetic detection system is operated. The static or gradient field strength in or near the working region needs to meet certain requirements to ensure proper operation of the magnetic detector (e.g. atomic magnetometer, giant magnetoresistance), e.g. a background magnetic field (typically <20 nT) that is extremely low and spatially distributed uniformly.
The magnetic field compensation means are arranged in or near the working area 6 of the magnetic shielding room to detect the magnetic field strength in the working area 6, which magnetic field compensation means may comprise, for example, a first magnetic detector 1 and a second magnetic detector 2 as shown in fig. 1.
The first magnetic detector 1 and the second magnetic detector 2 employ magnetic detectors of different detection ranges. The detection range of the first magnetic detector 1 is larger than that of the second magnetic detector 2, and the purpose of the detection range is to adopt the magnetic detectors with more than two different detection ranges to cooperate, firstly, the magnetic field intensity in the working area is detected by the first magnetic detector 1 (such as giant magnetoresistance) with a larger working range, and the magnetic field compensation operation is performed based on the detection result of the first magnetic detector 1, so that the magnetic field intensity in the working area 6 is compensated to a first magnetic field state, such as 5-20nT.
In the first magnetic field state, the second magnetic detector 2 can work normally, the second magnetic detector 2 has higher magnetic field detection precision, and further magnetic field compensation operation can be performed based on the detection result of the second magnetic detector 2, so that the magnetic field intensity in the working area 6 is compensated to a second magnetic field state with smaller magnetic field intensity, for example, 10pT-5nT.
The detection range comprises not only the magnetic field intensity detection range of the magnetic detector but also the magnetic field frequency detection range, and the invention realizes the concept of magnetic field detection and active compensation through cooperation of at least two magnetic detectors, and can be realized based on different magnetic field intensity detection ranges, different magnetic field frequency detection ranges and different magnetic field intensity detection ranges and different magnetic field frequency detection ranges.
The first magnetic detector 1 is illustratively at least one of a giant magnetoresistance, a fluxgate, a hall effect device, or a diamond hole magnetometer. Low-precision, high-bandwidth active magnetic field compensation is achieved by the first magnetic detector 1.
The detection range of the first magnetic detector 1 may be, for example, a magnetic field strength detection range of 0 to 100,000nt and a frequency detection range of 0 to 2000Hz. Illustratively, the first magnetic detector 1 may have a smaller magnetic field strength detection range, for example, 0 to 50,000nt, 0 to 30,000nt, or 0 to 10,000nt, and may also have a smaller frequency detection range, for example, 0 to 2000Hz, 0 to 1000Hz, or 0 to 500Hz. Illustratively, the first magnetic detector 1 may have a larger magnetic field strength detection range, for example, 0 to 200,000nt, 0 to 400,000nt, or 0 to 600,000nt. The first magnetic detector 1 may have a larger magnetic field frequency detection range, for example 0 to 4000Hz, 0 to 6000Hz or 0 to 8000Hz, for example.
The second magnetic detector 2 is illustratively an atomic magnetometer without spin-exchange relaxation effects. As mentioned above, the atomic magnetometer without spin-exchange relaxation effect (also called SERF effect atomic magnetometer) has a higher detection accuracy although the dynamic range is small, and can realize high-accuracy and limited-bandwidth active magnetic field compensation within the working bandwidth.
The detection range of the second magnetic detector 2 may be, for example, a magnetic field strength detection range of 0 to 20nT and a magnetic field frequency detection range of 0 to 200Hz. Illustratively, the second magnetic detector 2 may have a smaller magnetic field strength detection range, for example 0 to 10nT; it is also possible to have a smaller magnetic field frequency detection range, for example 0 to 150Hz, 0 to 100Hz or 0 to 50Hz. Illustratively, the second magnetic detector 2 may have a larger magnetic field strength detection range, for example 0 to 30nT or 0 to 50nT; it is also possible to have a larger magnetic field frequency detection range, for example 0 to 250Hz, 0 to 300Hz or 0 to 500Hz.
The above has shown an embodiment in which the magnetic field detection means comprise two different detection ranges of magnetic detectors, to which the invention is not limited. In alternative embodiments, the magnetic field detection means may comprise more than two different detection range magnetic detectors, e.g. three or more, each having a detection range from large to small, thereby achieving different detection range gradients to meet the practical requirements of the respective active magnetic field compensation.
In addition, the invention is not limited to the number and arrangement of each magnetic detector, and the different magnetic detectors may be arranged in pairs or groups. For example, as shown in fig. 2, the first magnetic detector 1 and the second magnetic detector 2 may be arranged close in pairs. Alternatively, the first magnetic detector 1 and the second magnetic detector 2 may also be arranged remote from each other. The number of each type of magnetic detector is at least one, and the number of each type of magnetic detector may be the same (e.g., arranged in pairs) or may be different.
The magnetic field compensation means may also comprise, for example, a magnetic detector holder (not shown) for holding the magnetic field detection means for positioning the magnetic detectors for the different number and arrangement of magnetic detectors described above.
The control system 4 may be configured to receive a signal indicative of the magnitude of the magnetic field strength detected by the magnetic field detection means, the signal being indicative of the static magnetic field strength or the gradient magnetic field strength in the working region. The control system 4 compares the detected static magnetic field strength or gradient magnetic field strength with a preset threshold value, and when the detected static magnetic field strength or gradient magnetic field strength is greater than the threshold value, the control system 2 generates a control signal to control the driving device 5 to generate a driving signal (e.g., a driving current) to drive the coil.
The control system 4 may also comprise a processor for controlling the operation of the degaussing means based on a built-in software program or a programmable hardware system or user instructions. The processor may be a micro control unit (Micro Controller Unit, MCU), field Programmable Gate Array (FPGA) or digital signal processor, CPU, desktop computer, workstation, etc. as is common in the art with data receiving and processing capabilities.
The drive means 5 apply a drive signal to the magnetic field generator 3 under the control of the control system 4. The driving means 3 comprise, for example, a power amplifier, by means of which the driving means 3 receive the driving signal of the control system 4 and drive the magnetic field generator 3.
The magnetic field compensation device may, for example, further comprise a work target object tracking device for tracking a target object within the work area.
On the other hand, the invention also provides a magnetic shielding system which comprises the magnetic field compensation device.
As shown in fig. 2, the magnetic shielding system may include a magnetic shielding room, which may be constructed in a polyhedral or cylindrical form (in a square form in fig. 2), for example. The magnetic shielding chamber may further comprise a support structure (not shown) for supporting the magnetic field generator 3.
Fig. 3 shows a flow chart of a magnetic field compensation method according to an embodiment of the invention. A multi-detection mode magnetic field compensation method according to an exemplary embodiment of the present invention is described below with reference to fig. 3.
As shown in fig. 3, a magnetic field compensation method according to an exemplary embodiment of the present invention includes the following steps:
(a) Determining a first threshold and a second threshold size, wherein the second threshold is less than the first threshold;
(b) Detecting the magnetic field intensity in a working area of a magnetic shielding chamber through a first magnetic detector, and comparing the magnetic field intensity in the working area with a first threshold value;
(c) When the magnetic field in the working area is larger than a first threshold value, performing first magnetic field compensation operation, and reducing the magnetic field intensity in the working area to a first magnetic field state smaller than or equal to the first threshold value;
(d) Detecting the magnetic field intensity in the working area through a second magnetic detector when the magnetic field is in the first magnetic field state, and comparing the magnetic field intensity in the working area with a second threshold value;
(e) And when the magnetic field intensity in the working area is larger than a second threshold value, performing a second magnetic field compensation operation to reduce the magnetic field intensity in the working area to a second magnetic field state, wherein the range of the second magnetic field state is smaller than that of the first magnetic field state.
In the step (a), the magnitudes of the first threshold and the second threshold can be determined comprehensively according to the requirement of magnetic field compensation and the detection range of the magnetic detector. For example, the value of the first threshold is configured to be within the detection range of the first magnetic detector and outside the detection range of the second magnetic detector. Illustratively, the first threshold may be 10,000nt when the magnetic field strength of the first magnetic detector is detected in the range of 0 to 100,000 nt. Similarly, the value of the second threshold may be configured to be within the detection range of the second magnetic detector. Illustratively, the second threshold may be 15nT when the magnetic field strength detection range of the second magnetic detector is 0 to 20nT.
In step (b) and step (d), comparing the magnitude of the magnetic field strength detected by the first magnetic detector with the magnitude of the first threshold value and comparing the magnitude of the magnetic field strength detected by the second magnetic detector with the magnitude of the second threshold value, respectively, may be achieved by the control system.
In step (c), the first magnetic field compensation operation may, for example, include receiving, by the control system, a magnetic field strength signal detected by the first magnetic detector and generating a first drive signal. Then, a first drive signal is applied to the magnetic field generator to generate a compensation magnetic field, thereby reducing the magnetic field strength in the working region to a first magnetic field state.
In this embodiment, the first driving signal may include a current signal controlling the magnitude of the magnetic field generated by the magnetic field generator. Accordingly, the control system generating the first drive signal may include calculating a desired current signal magnitude based on the magnetic field strength signal detected by the first magnetic detector and outputting to the magnetic field generator.
In step (e), the second magnetic field compensation operation may, for example, include receiving magnetic field strength signals detected by the first magnetic detector and the second magnetic detector by the control system and generating a second drive signal. Then, a second drive signal is applied to the magnetic field generator to generate a compensation magnetic field, thereby reducing the magnetic field strength in the working region to a second magnetic field state.
Wherein, the detection range of the first magnetic detector is larger than that of the second magnetic detector. The first magnetic field state may for example range from 0 to 50nT, 0 to 30nT, 0 to 20nT or 0 to 10nT. The second magnetic field state may for example range from 10pT to 10nT, from 10pT to 5nT or from 10pT to 3nT.
In this embodiment, the second driving signal includes a current signal controlling the magnitude of the magnetic field generated by the magnetic field generator. Correspondingly, the control system generates a second driving signal, which comprises calculating the required current signal according to the magnetic field intensity signals detected by the first magnetic detector and the second magnetic detector, and controlling the same magnetic field generator in a current direct superposition mode.
In the second magnetic field compensation operation, the control system needs to receive the magnetic field intensity signals detected by the first magnetic detector and the second magnetic detector, so as to ensure that the magnetic field in the working area is always kept within the detection range of the second magnetic detector during the second magnetic field compensation operation.
When external interference occurs or the shielding system fails, the magnetic field in the working area may exceed the detection range of the second magnetic detector. At this time, since the control system also receives the detection result of the first magnetic detector, the control system may generate a corresponding driving signal to re-compensate the magnetic field, and repeat steps (d) and (e) after re-entering the first magnetic field state, so as to implement the second magnetic field state and continue to maintain the second magnetic field state. During this time, the control system may issue a warning message to the outside identifying the extent and time at which the working area magnetic field is out of the second magnetic field state.
Alternatively, the control system may also use other control methods to generate the second driving signal, for example, calculate the magnitude of the required current signal according to the magnetic field strength signals detected by the first magnetic detector and the second magnetic detector, and control the same magnetic field generator after performing the calculation by using a weighting algorithm. The weighting algorithm includes weight correction based on different detection frequencies.
For another example, the magnitude of the required current signal may be calculated according to the magnetic field intensity signals detected by the first magnetic detector and the second magnetic detector, and different magnetic field generators may be controlled.
Those skilled in the art can select a suitable control method according to the number of magnetic field generators, performance parameters, arrangement modes, and the like.
Illustratively, as shown in fig. 3, the magnetic field compensation method of the present embodiment may further include:
(f) And outputting information indicating that the magnetic field intensity in the working area meets the requirement when the magnetic field intensity in the working area is smaller than or equal to a preset range. The preset range can be selected according to actual needs, and the main purpose of the step (f) is to indicate that the magnetic field compensation device is in a normal working state, and the magnetic field intensity in the working area meets the working requirements.
Illustratively, the magnetic field compensation method of the present embodiment may further include:
(g) And when the magnetic field is in the second magnetic field state, continuously detecting the magnetic field intensity in the working area through the second magnetic detector, and performing a second magnetic field compensation operation according to the magnetic field intensity signal detected by the second magnetic detector.
In the step (g), the second magnetic detector can continuously detect the magnetic field intensity in the working area at a certain time interval, and correspondingly adjust the driving signal in the second magnetic field compensation operation, so as to ensure that the working environment of the required low static magnetic field and low gradient field is always maintained in the working process.
The exemplary embodiments of the multi-detection mode magnetic field compensation device, the magnetic field compensation method and the magnetic shielding system proposed by the present invention have been described in detail hereinabove with reference to preferred embodiments, however, it will be understood by those skilled in the art that various modifications and adaptations can be made to the specific embodiments described above without departing from the concept of the present invention. In addition, various technical features and structures presented in various aspects of the present invention may be combined in various ways without departing from the scope of the invention, which is defined by the appended claims.
Claims (20)
1. A multi-detection mode magnetic field compensation method comprises the following steps:
determining a first threshold and a second threshold size, wherein the second threshold is less than the first threshold;
detecting the magnetic field intensity in a working area of a magnetic shielding chamber through a first magnetic detector, and comparing the magnetic field intensity in the working area with a first threshold value;
when the magnetic field in the working area is larger than a first threshold value, performing first magnetic field compensation operation, and reducing the magnetic field intensity in the working area to a first magnetic field state smaller than or equal to the first threshold value;
detecting the magnetic field intensity in the working area through a second magnetic detector when the magnetic field is in the first magnetic field state, and comparing the magnetic field intensity in the working area with a second threshold value;
and when the magnetic field intensity in the working area is larger than a second threshold value, performing a second magnetic field compensation operation to reduce the magnetic field intensity in the working area to a second magnetic field state, wherein the range of the second magnetic field state is smaller than that of the first magnetic field state.
2. The magnetic field compensation method of claim 1, further comprising:
and outputting information indicating that the magnetic field intensity in the working area meets the requirement when the magnetic field intensity in the working area is smaller than or equal to a preset range.
3. The magnetic field compensation method of claim 1, wherein the first magnetic field compensation operation comprises:
receiving a magnetic field intensity signal detected by a first magnetic detector through a control system and generating a first driving signal;
a first drive signal is applied to the magnetic field generator to generate a compensating magnetic field to reduce the magnetic field strength in the working region to a first magnetic field state.
4. A magnetic field compensation method according to claim 3, wherein the second magnetic field compensation operation comprises:
receiving magnetic field intensity signals detected by a first magnetic detector and a second magnetic detector through a control system, and generating a second driving signal, wherein the detection range of the first magnetic detector is larger than that of the second magnetic detector;
a second drive signal is applied to the magnetic field generator to generate a compensating magnetic field to reduce the magnetic field strength in the working region to a second magnetic field state.
5. The magnetic field compensation method of claim 4, further comprising:
and when the magnetic field is in the second magnetic field state, continuously detecting the magnetic field intensity in the working area through the second magnetic detector, and performing a second magnetic field compensation operation according to the magnetic field intensity signal detected by the second magnetic detector.
6. A magnetic field compensation method according to claim 3 wherein the first drive signal comprises a current signal controlling the magnitude of the magnetic field generated by the magnetic field generator.
7. The magnetic field compensation method of claim 6 wherein the control system generating the first drive signal comprises: and calculating the magnitude of the required current signal according to the magnetic field intensity signal detected by the first magnetic detector, and outputting the current signal to the magnetic field generator.
8. The magnetic field compensation method of claim 4 wherein the second drive signal comprises a current signal that controls the magnitude of the magnetic field generated by the magnetic field generator.
9. The magnetic field compensation method of claim 8 wherein the control system generating the second drive signal comprises: and respectively calculating the required current signals according to the magnetic field intensity signals detected by the first magnetic detector and the second magnetic detector, and controlling the same magnetic field generator in a current direct superposition mode.
10. The magnetic field compensation method of claim 8 wherein the control system generating the second drive signal comprises: and respectively calculating the magnitude of the required current signals according to the magnetic field intensity signals detected by the first magnetic detector and the second magnetic detector, and controlling the same magnetic field generator after calculation through a weighting algorithm.
11. The magnetic field compensation method of claim 10 wherein the weighting algorithm comprises weight correction based on different detection frequencies.
12. The magnetic field compensation method of claim 8 wherein the control system generating the second drive signal comprises: and respectively calculating the magnitude of the required current signal according to the magnetic field intensity signals detected by the first magnetic detector and the second magnetic detector, and respectively controlling different magnetic field generators.
13. A multi-detection mode magnetic field compensation device, comprising:
a magnetic field generator for generating a compensation magnetic field in a working area of the magnetic shielding chamber;
a magnetic field detection device for detecting the magnetic field intensity in the working area;
a control system that receives a signal indicative of the magnitude of the magnetic field strength detected by the magnetic field detection device; and
a driving device which applies a driving signal to the magnetic field generator under the control of the control system to reduce the magnetic field intensity in the working area to a predetermined range,
the magnetic field detection device comprises a first magnetic detector and a second magnetic detector, and the detection range of the first magnetic detector is larger than that of the second magnetic detector.
14. The magnetic field compensation device of claim 13, wherein the magnetic field generator is a coil.
15. The magnetic field compensation apparatus of claim 13 wherein the first magnetic detector is at least one of a giant magnetoresistance, a fluxgate, a hall effect device, or a diamond hole magnetometer.
16. The magnetic field compensation apparatus of claim 13 wherein the first magnetic detector has a magnetic field strength detection range of 0 to 100,000nt and a frequency detection range of 0 to 2000Hz.
17. The magnetic field compensation apparatus of claim 13 wherein the second magnetic detector is a spin-free relaxation effect atomic magnetometer.
18. The magnetic field compensation apparatus of claim 13 wherein the second magnetic detector has a magnetic field strength detection range of 0 to 20nT and a frequency detection range of 0 to 200Hz.
19. The magnetic field compensation device of claim 13, further comprising: and the working target object tracking device is used for tracking the target object in the working area.
20. A magnetic shielding system comprising a magnetic field compensation device according to any one of claims 13-19.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111373386.7A CN116148727A (en) | 2021-11-19 | 2021-11-19 | Multi-detection mode magnetic field compensation device, magnetic field compensation method and magnetic shielding system |
| PCT/CN2022/132501 WO2023088352A1 (en) | 2021-11-19 | 2022-11-17 | Multi-detection-mode magnetic field compensation device, magnetic field compensation method, and magnetic shielding system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111373386.7A CN116148727A (en) | 2021-11-19 | 2021-11-19 | Multi-detection mode magnetic field compensation device, magnetic field compensation method and magnetic shielding system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116148727A true CN116148727A (en) | 2023-05-23 |
Family
ID=86358640
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111373386.7A Pending CN116148727A (en) | 2021-11-19 | 2021-11-19 | Multi-detection mode magnetic field compensation device, magnetic field compensation method and magnetic shielding system |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN116148727A (en) |
| WO (1) | WO2023088352A1 (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005003503A (en) * | 2003-06-11 | 2005-01-06 | Foresutekku:Kk | Magnetic-shielding method using induction coil |
| 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 |
| CN109597010A (en) * | 2018-12-04 | 2019-04-09 | 北京昆迈生物医学研究院有限公司 | A kind of high-performance magnetism screening arrangement and method based on Active Compensation |
| 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 |
| CN110426651B (en) * | 2019-06-17 | 2020-11-27 | 北京航空航天大学 | Three-dimensional in-situ magnetic coil calibration experimental device and method based on SERF magnetometer |
| CN112837889B (en) * | 2020-01-08 | 2023-04-07 | 中科知影(北京)科技有限公司 | Large-scale magnetic shielding system and demagnetization device and demagnetization method thereof |
-
2021
- 2021-11-19 CN CN202111373386.7A patent/CN116148727A/en active Pending
-
2022
- 2022-11-17 WO PCT/CN2022/132501 patent/WO2023088352A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO2023088352A1 (en) | 2023-05-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113498479A (en) | Correcting magnetic hysteresis in magnetic resonance imaging | |
| Afach et al. | Dynamic stabilization of the magnetic field surrounding the neutron electric dipole moment spectrometer at the Paul Scherrer Institute | |
| US5200701A (en) | Magnetic resonance imaging apparatus with regulator for reducing eddy current effects | |
| US20150369887A1 (en) | Methods and apparatuses related to instrumentation for magnetic relaxometry measurements | |
| US10261148B2 (en) | Magnetic resonance imaging apparatus and manufacturing method thereof | |
| CN112837889B (en) | Large-scale magnetic shielding system and demagnetization device and demagnetization method thereof | |
| US20210386346A1 (en) | Magnetoencephalograph and brain's magnetic field measurement method | |
| KR101565678B1 (en) | Mr system with pulsed compensation magnetic field gradients | |
| CN112130217A (en) | System and method for electrically detecting included angle between geometric axis and magnetic axis of coil vector magnetometer | |
| Yang et al. | Calibration of SQUID magnetometers in multichannel MCG system based on bi-planar coil | |
| JP2013217690A (en) | Magnetic field correction device and magnetic field measuring device | |
| US7315168B2 (en) | Shimming with MRI gradient | |
| US11914012B2 (en) | Brain measurement apparatus and brain measurement method | |
| US6960914B2 (en) | Methods and apparatus for imaging systems | |
| CN116148727A (en) | Multi-detection mode magnetic field compensation device, magnetic field compensation method and magnetic shielding system | |
| CN114264984B (en) | Method and system for measuring weak magnetic field of zero-field optical pump atomic magnetometer | |
| JPH03224538A (en) | Mri device provided with process for correcting primary magnetostatic field ununiformity and executing measurement | |
| JP3655425B2 (en) | Biomagnetic field measurement device | |
| EP4040178A1 (en) | Magnetic resonance imaging device, computer-implemented method for operating a magnetic resonance imaging device, computer program and electronically readable storage medium | |
| JP4363856B2 (en) | Method for influencing a uniform static magnetic field in the z-axis direction in a nuclear magnetic resonance apparatus, and a nuclear magnetic resonance resonator | |
| US7358726B2 (en) | System of generating a magnetic field and MRI system using the system of generating a magnetic field | |
| JPH02264636A (en) | Nuclear magnetic resonance method | |
| KR101799046B1 (en) | Ultra Low Magnetic Field Nuclear Magnetic Resonance Apparatus | |
| Yue et al. | Micro-Fabricated SERF Atomic Magnetometer for Weak Gradient Magnetic Field Detection | |
| JP2002017706A (en) | Magnetic resonance imaging device with function of measuring magnetic field fluctuation with high accuracy |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |