Alternating gradient magnetometer calibration method and device, device using method, medium and equipment

Abstract

The invention provides an alternating gradient magnetometer calibration method. The alternating gradient magnetometer calibration method comprises the steps that a calibration coil is arranged at a sample fixing position of a sample rod; a calibration current is introduced into the calibration coil, and the magnetization intensity of the calibration coil is calculated; exciting current is introduced into the gradient coil to generate a gradient magnetic field, so that the calibration coil vibrates in the gradient magnetic field; changing the frequency of the exciting current to obtain the resonance amplitude of the calibration coil through a gradient magnetic field; according to the resonance amplitude of the calibration coil and the magnetization intensity of the calibration coil, the actual magnetic field gradient of the gradient coil under the excitation current is calculated; calibrating a gradient magnetic field according to the actual magnetic field gradient; the gradient magnetic field can be corrected, and the detection precision of the alternating gradient magnetometer is effectively improved. The invention further provides a using method of the alternating gradient magnetometer device and the alternating gradient magnetometer device.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic detection, and relates to an alternating gradient magnetometer, and in particular to an alternating gradient magnetometer calibration method and device, a method for using the device, a medium, and equipment. Background Art

[0002] The alternating gradient magnetometer is a high-precision magnetic measurement device that determines the magnetic moment of the object being measured by measuring the force exerted on the object in the gradient magnetic field. Usually, the object being measured needs to be placed in an alternating gradient magnetic field to make it vibrate. The magnetic moment of the object being measured can be calculated by detecting the vibration of the object being measured and combining it with the alternating gradient magnetic field.

[0003] An accurate alternating gradient magnetic field is a necessary step for accurately measuring the magnetic moment of the object under test. In the prior art, an alternating gradient magnetic field is mainly generated by an excitation coil. In order to accurately calculate the magnetic moment of the object under test, it is necessary to obtain an accurate gradient magnetic field. Therefore, it is necessary to calibrate the gradient magnetic field generated by the excitation coil to avoid a large difference between the actual magnetic field of the gradient coil and the magnetic field data used to calculate the magnetic moment of the object under test, thereby reducing the error in measuring the magnetic moment of the object under test.

[0004] Therefore, it is necessary to calibrate the alternating gradient magnetic field of the alternating gradient magnetometer.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0006] In order to provide a method for calibrating an alternating gradient magnetic field of an alternating gradient magnetometer, the present invention provides an alternating gradient magnetometer calibration method, comprising: arranging a calibration coil at a sample fixing position of a sample rod; S1: passing a calibration current into the calibration coil and calculating the magnetization intensity of the calibration coil; S2: passing an excitation current into the gradient coil to generate a gradient magnetic field, so that the calibration coil vibrates in the gradient magnetic field; changing the frequency of the excitation current to obtain the resonance amplitude of the calibration coil with the gradient magnetic field; S3: calculating the actual magnetic field gradient of the gradient coil under the excitation current according to the resonance amplitude of the calibration coil and the magnetization intensity of the calibration coil; S4: Calibrate the gradient magnetic field according to the actual magnetic field gradient.

[0007] According to one embodiment of the present invention, the S4 further includes: calculating the theoretical magnetic field gradient of the gradient coil according to the excitation current of the gradient coil; and calibrating the gradient magnetic field according to the actual magnetic field gradient and the theoretical magnetic field gradient.

[0008] According to one embodiment of the present invention, S4 includes: changing the calibration current, performing S1-S3 multiple times, and obtaining multiple sets of data pairs of actual magnetic field gradients and theoretical magnetic field gradients; and calculating the mapping relationship between the actual magnetic field gradient and the theoretical magnetic field gradient based on the data pairs.

[0009] According to one embodiment of the present invention, S4 includes: calculating the difference between the actual magnetic field gradient and the theoretical magnetic field gradient, and if the difference is less than a preset threshold, ending the calibration; otherwise, adjusting the excitation current and performing S2-S4 again until the difference between the actual magnetic field gradient and the theoretical magnetic field gradient is less than a preset threshold.

[0010] According to one embodiment of the present invention, S4 includes: changing the excitation current, performing S1-S3 multiple times, and obtaining multiple sets of data pairs of excitation current and actual magnetic field gradient; and calculating the mapping relationship between the excitation current and the actual magnetic field gradient based on the data pairs.

[0011] According to one embodiment of the present invention, in S3, the mapping relationship between the resonance amplitude of the calibration coil and the magnetic force applied to the calibration coil is used as the first mapping relationship, and the magnetic force applied to the calibration coil is calculated based on the resonance amplitude of the calibration coil and the first mapping relationship; and the actual magnetic field gradient of the gradient coil under the excitation current is calculated based on the magnetic force applied to the calibration coil and the magnetization intensity.

[0012] According to one embodiment of the present invention, the first mapping relationship also responds to the mass of the calibration coil and the resonant frequency of the calibration coil; S2 also includes obtaining the mass and the resonant frequency of the calibration coil; S3 also includes: determining the first mapping relationship through the mass and the resonant frequency of the calibration coil.

[0013] According to one embodiment of the present invention, a current is passed through the calibration coil to calculate the magnetization intensity of the calibration coil; a calibrated gradient coil is used to generate a known gradient magnetic field, and the calibration coil is vibrated in the known gradient magnetic field to obtain the resonance amplitude of the calibration coil; the magnetic force exerted on the calibration coil is calculated based on the known gradient magnetic field and the magnetization intensity of the calibration coil; at least one of the current passed through the calibration coil and the calibrated gradient coil is adjusted to obtain multiple sets of fitting data pairs of the magnetic force exerted on the calibration coil and the resonance amplitude, and the first mapping relationship is fitted based on the fitting data pairs.

[0014] The present invention also provides a method for using an alternating gradient magnetometer device, comprising: A1: installing a calibration coil on a sample rod; A2: passing a calibration current into the calibration coil, turning on the gradient coil, and using the calibration coil to calibrate the gradient magnetic field generated by the gradient coil; A3: Remove the calibration coil and install the object to be measured on the sample rod; A4: Turn on the gradient coil and generate a gradient magnetic field to detect the object under test.

[0015] The present invention also provides an alternating gradient magnetometer device, comprising: a gradient coil for generating a gradient magnetic field; a sample rod for mounting a measured object or a calibration coil; a calibration device for calibrating the gradient magnetic field; and a vibration detection device for detecting vibration of at least one of the measured object, the calibration coil, and the sample rod; The gradient coil responds to the signal of the calibration device, and the calibration device responds to the current signal of the gradient coil, the current signal of the calibration coil, and the output signal of the vibration detection device; the calibration device is constructed in a form capable of executing the alternating gradient magnetometer calibration method as described above.

[0016] The present invention provides a computer storage medium, which is used to store a program, wherein when the program is running, the device where the computer storage medium is located is controlled to execute the above-mentioned alternating gradient magnetometer calibration method.

[0017] The present invention provides an electronic device, comprising a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to execute the aforementioned alternating gradient magnetometer calibration method through the computer program.

[0018] The present invention has at least the following beneficial effects: the alternating gradient magnetometer calibration method provided by the present invention simulates a known object to be measured by using a calibration coil, and calculates the corresponding magnetization intensity and force conditions and the corresponding magnetic field gradient through the vibration state of the calibration coil and the calibration current, thereby calibrating the gradient magnetic field and ensuring the accuracy of the detection of the alternating gradient magnetometer. The present invention also provides a method for using an alternating gradient magnetometer device, which can achieve high-precision detection of the object to be measured and reduce detection errors. The present invention also provides an alternating gradient magnetometer device, which can run the aforementioned alternating gradient magnetometer calibration method and method of use, can achieve the calibration of the alternating gradient magnetometer, and perform high-precision detection of the object to be measured and reduce detection errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1The figure is a schematic diagram of the overall structure of an embodiment of an alternating gradient magnetometer.

[0020] Figure 2 It is a schematic diagram of the overall structure of another embodiment of an alternating gradient magnetometer. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. It should be noted that the drawings are all in a very simplified form and use inaccurate ratios, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0022] The present invention firstly provides an alternating gradient magnetometer calibration method, which calibrates the gradient magnetic field in the alternating gradient magnetometer so as to make the gradient magnetic field data used for calculating the magnetic moment of the measured object closer to the actual gradient magnetic field data, thereby improving the detection accuracy of the alternating gradient magnetometer.

[0023] Specifically, see Figure 1 , Figure 2 The present invention simulates the object to be measured by using a calibration coil, and fixes the calibration coil to the sample fixing position 120 of the sample rod 110. Generally, the electromagnetic characteristics of the calibration coil are known, that is, the magnetization intensity of the calibration coil can be calculated by passing the current through the calibration coil to correspond to the magnetic moment to be measured of the object to be measured; in some cases, according to the structure of the calibration coil, the mapping relationship between the current passed through the calibration coil and the magnetization intensity of the calibration coil can be inferred, so that the magnetization intensity of the calibration coil can be calculated by passing the current through the calibration coil to correspond to the magnetic moment to be measured of the object to be measured.

[0024] In order to know the relationship between the magnetization intensity of the calibration coil and the current passed through the calibration coil, or to know the magnetization intensity of the calibration coil under a certain current condition, the magnetization intensity of the calibration coil can be detected by a magnetic field measuring device. For example, the magnetic field near the calibration coil can be detected by a magnetic sensor such as a Hall probe to determine the magnetization intensity of the calibration coil.

[0025] The calibration process generally includes the following steps: S1: Pass a calibration current into the calibration coil to calculate the magnetization of the calibration coil. The calculation of the magnetization of the calibration coil is relatively simple and accurate, so the magnetization of the calibration coil can be calculated based on the calibration current to simulate the object under test with the same magnetization or magnetic moment.

[0026] S2: passing an excitation current into the gradient coil 220 to generate a gradient magnetic field, causing the calibration coil to vibrate in the gradient magnetic field; changing the frequency of the excitation current to change the vibration frequency of the calibration coil, and obtaining the resonance amplitude of the calibration coil.

[0027] In some cases, the gradient coil 220 needs to generate an alternating gradient magnetic field so that the calibration coil vibrates under the action of the alternating gradient magnetic field generated by the gradient coil 220; the vibration frequency of the calibration coil is adjusted by adjusting the frequency of the alternating gradient magnetic field. The frequency of the alternating gradient magnetic field can be adjusted at least by adjusting the frequency of the current flowing into the gradient coil 220.

[0028] For the resonant frequency of the calibration coil, the vibration frequency of the calibration coil can be changed by keeping the intensity of the gradient magnetic field roughly unchanged and changing the frequency, and at the same time detecting the vibration amplitude of the calibration coil at different vibration frequencies. When the vibration amplitude of the calibration coil reaches the maximum, it indicates that the calibration coil has reached a resonant state. The vibration frequency and vibration amplitude at this time can be used as the resonant frequency and the resonant amplitude, respectively.

[0029] S3: Calculate the actual magnetic field gradient of the gradient coil under the excitation current based on the resonance amplitude of the calibration coil and the magnetization intensity of the calibration coil. The vibration amplitude of the calibration coil can reflect the force on the calibration coil, so the force condition of the gradient coil can be obtained based on the resonance amplitude. Furthermore, in S1, based on the magnetization intensity of the calibration coil, the actual gradient magnetic field in which the calibration coil is located can be calculated based on the magnetization intensity and force condition of the calibration coil to obtain the actual magnetic field gradient.

[0030] S4: Calibrate the gradient magnetic field according to the actual magnetic field gradient. The magnetic field gradient of the gradient magnetic field is the main calibration object of the alternating gradient magnetometer. Therefore, when the actual magnetic field gradient of the gradient coil is known, the actual magnetic field gradient used to detect the object under test can be known, thereby realizing the calibration of the alternating gradient magnetometer.

[0031] For the calibration method of the gradient magnetic field in the aforementioned S4, the gradient magnetic field can be calibrated by the difference between the theoretical magnetic field gradient and the actual magnetic field gradient. Accordingly, the theoretical magnetic field gradient of the gradient coil 220 can be calculated according to the excitation current passed into the gradient coil 220 and the structure of the gradient coil 220, so as to be used for the calibration of the gradient magnetic field.

[0032] Specifically, as a feasible method, S4 includes: changing the calibration current, performing S1-S3 multiple times, and obtaining multiple sets of data pairs of actual magnetic field gradients and theoretical magnetic field gradients; and calculating the mapping relationship between the actual magnetic field gradient and the theoretical magnetic field gradient based on the data pairs.

[0033] The mapping relationship between the actual magnetic field gradient and the theoretical magnetic field gradient can usually be a fixed value. For example, when the excitation current remains unchanged, the gradient field generated by the gradient coil 220 remains substantially unchanged, that is, the actual magnetic field gradient remains substantially unchanged. At this time, the difference between the theoretical magnetic field gradient and the actual magnetic field gradient remains substantially fixed. By adjusting the calibration current to form different magnetization intensities of the calibration coil, multiple actual magnetic field gradient values ​​are calculated based on the magnetization intensities of the calibration coil, and calculations are performed based on the multiple actual magnetic field gradient values ​​to obtain the corresponding actual magnetic field gradient, so as to reduce errors and improve accuracy; in addition, the influence of extreme values ​​can be avoided by using corresponding data processing methods.

[0034] In some cases, the magnetic field gradients at different positions of the gradient magnetic field are different, and it is difficult to meet the requirements of gradient magnetic field calibration using fixed values. Accordingly, the gradient magnetic field can be calibrated more accurately by establishing a mapping relationship between the theoretical magnetic field gradient and the actual magnetic field gradient. Specifically, under different calibration currents, the vibration amplitude of the calibration coil is different. Accordingly, the magnetic field gradients at different positions of the gradient magnetic field can be calibrated, and then the mapping relationship between the actual magnetic field gradient at different positions and the theoretical magnetic field gradient can be obtained, so as to calibrate the gradient magnetic field more accurately.

[0035] In some cases, the gradient magnetic field required for the detection of the alternating gradient magnetometer is already clear. Accordingly, the actual magnetic field gradient can be calculated by the calibration coil, and the excitation current is adjusted according to the magnetic field gradient required for the detection to adjust the actual magnetic field gradient, so that the actual magnetic field gradient is close to or reaches the magnetic field gradient required for the detection. Specifically, the magnetic field gradient required for the detection is used as the theoretical magnetic field gradient, and the magnetic field gradient calculated by the calibration coil is the actual magnetic field gradient. The difference between the actual magnetic field gradient and the theoretical magnetic field gradient is calculated. If the difference is less than the preset threshold, the calibration is terminated; otherwise, the excitation current passed into the gradient coil 220 is adjusted, and S2-S4 is performed again to calculate the difference between the actual magnetic field gradient and the theoretical magnetic field gradient and evaluate until the difference between the actual magnetic field gradient and the theoretical magnetic field gradient is less than the preset threshold, that is. The difference between the actual magnetic field gradient and the magnetic field gradient required for detection is less than the preset threshold. The preset threshold can be set according to the needs of the detection, and the specific setting method is not repeated here.

[0036] In some cases, in addition to calibrating the gradient coils and specific target gradient magnetic fields in specific states, it is also necessary to calibrate the characteristics of the gradient magnetic field generated by the gradient coils 220, so that the gradient coils 220 can form a high-precision gradient magnetic field under different gradient magnetic field requirements. Accordingly, the excitation current passed through the gradient coils 220 can be changed multiple times, and S1-S3 can be performed multiple times to obtain multiple sets of data pairs of excitation currents and actual magnetic field gradients; based on the data pairs, the mapping relationship between the excitation current and the actual magnetic field gradient is calculated. In this way, the actual magnetic field gradient can be obtained by passing the excitation current through the gradient coils 220, so that the gradient coils 220 can meet any gradient magnetic field requirements. It should be noted that the mapping relationship between the excitation current and the actual magnetic field gradient can be either a continuous mapping relationship obtained by fitting or a discrete mapping relationship composed of data pairs; when a continuous mapping relationship is obtained, the excitation current can be input into the mapping relationship to obtain the actual magnetic field gradient; when a discrete mapping relationship is obtained, the data pair closest to the input excitation current can be found in the data pair, and the corresponding actual magnetic field gradient can be output based on the closest data pair; it can also be a combination of the above two, and the specific combination method will not be repeated here.

[0037] In S3, the actual magnetic field gradient of the gradient coil under the excitation current can be calculated according to the resonance amplitude of the calibration coil and the magnetization intensity of the calibration coil. Specifically, the calculation can be performed in the following manner: taking the mapping relationship between the resonance amplitude of the calibration coil and the magnetic force exerted on the calibration coil as the first mapping relationship, the magnetic force exerted on the calibration coil is calculated according to the resonance amplitude of the calibration coil and the first mapping relationship; and calculating the actual magnetic field gradient of the gradient coil 220 under the excitation current according to the magnetic force exerted on the calibration coil and the magnetization intensity.

[0038] For the first mapping relationship, it is mainly determined by the characteristics of the device itself, specifically, it is mainly determined by the characteristics of the system composed of the sample rod 110 and the object to be measured or the calibration coil fixed thereon, which can be reflected as the natural frequency of the system composed of the sample rod 110 and the object to be measured or the calibration coil fixed thereon, and the mass of the object to be measured or the calibration coil. For the natural frequency, the frequency when the object to be measured or the calibration coil is vibrated in the gradient field to reach a resonant state can be used as the resonant frequency, which is then used to calculate the natural frequency. Since the sample rod 110 is usually a hard rod fixed at one end and is arranged in a form similar to a cantilever beam, the influence of the system damping can be generally ignored, and the resonant frequency can be used as the natural frequency. Therefore, the measured resonant frequency can be used as a parameter in the mapping relationship.

[0039] The first mapping relationship is also related to the mass of the object to be measured or the calibration coil set on the sample rod 110. However, under normal circumstances, the mass of the object to be measured or the calibration coil can be directly measured and is known, so the mass of the object to be measured or the calibration coil only serves as a parameter in the mapping relationship. Accordingly, without replacing the sample rod 110, the object to be measured or the calibration coil is installed in the sample fixing position 120 of the sample rod 110. After knowing the mass of the object to be measured or the calibration coil, the first mapping relationship is immediately determined, so the force on the object to be measured or the calibration coil can be calculated based on the determined first mapping relationship combined with the resonance amplitude. Therefore, when the mass of the object to be measured or the calibration coil and the first mapping relationship are known, the magnetic force on the object to be measured or the calibration coil can be calculated, and then the magnetization intensity of the object to be measured is calculated in combination with the magnetic field gradient, or the magnetic field gradient is calculated in combination with the magnetization intensity of the calibration coil.

[0040] In summary, S2 may further include obtaining the mass and the resonance frequency of the calibration coil; and S3 may further include determining the first mapping relationship through the mass and the resonance frequency of the calibration coil.

[0041] More specifically, the first mapping relationship can be determined in the following manner: current is passed through the calibration coil, the calibration coil is known, and the magnetization intensity of the calibration coil can be calculated; the calibration coil is vibrated under the action of a known alternating gradient magnetic field, and the magnetic force exerted on the calibration coil is calculated through the magnetization intensity and the alternating gradient magnetic field, and at the same time, the resonance amplitude of the calibration coil is obtained, thereby obtaining a data pair of the magnetic force exerted on the calibration coil and the resonance amplitude of the calibration coil. At least one of the currents passed through the calibration coil and the calibrated gradient coil 220 is adjusted multiple times to obtain multiple groups of data pairs as fitting data pairs, and the first mapping relationship is fitted therewith. Accordingly, the calibrated gradient coil 220 can be used to generate an alternating gradient magnetic field, or a known gradient coil 220 can be used to generate an alternating gradient magnetic field.

[0042] Accordingly, the present invention also provides a method for using an alternating gradient magnetometer device, comprising: A1: Install the calibration coil on the sample rod 110. Since the calibration coil needs to be energized, the leads of the calibration coil need to be installed during the installation of the calibration coil so that the corresponding calibration current can be input into the calibration coil. The leads of the calibration coil need not interfere with the vibration of the sample rod 110. Normally, the leads can be made in a non-tightened state, a certain interval can be set between the leads and the sample rod 110, and / or other methods can be used to avoid the influence of the leads on the vibration of the sample rod 110. Of course, in some cases, the sample rod 110 can also be integrated with leads so that the calibration coil is energized through the leads integrated in the sample rod 110. When the calibration coil is removed, the leads remain on the sample rod 110.

[0043] A2: A calibration current is passed into the calibration coil, the gradient coil 220 is turned on, and the calibration coil is used to calibrate the gradient magnetic field generated by the gradient coil. The specific calibration process can refer to the above calibration process, which will not be described in detail here.

[0044] A3: Remove the calibration coil and install the object to be measured on the sample rod 110. It should be noted that the positions of the object to be measured and the calibration coil on the sample rod 110 are substantially the same; when a sample fixing position 120 is provided on the sample rod 110, the calibration coil and the object to be measured can be fixed to the sample fixing position 120 respectively to avoid differences in their positions.

[0045] A4: Turn on the gradient coil and generate a gradient magnetic field to detect the object to be measured. At this time, the gradient coil 220 has been calibrated, and the alternating gradient magnetic field used to calculate the magnetic properties of the object to be measured is more accurate.

[0046] In addition, the present invention also provides an alternating gradient magnetometer device, which at least includes a gradient coil 220, a sample rod 110, a calibration device, and a vibration detection device.

[0047] The gradient coil 220 can be used to generate a gradient magnetic field. Figure 1 , Figure 2 As a feasible implementation, the gradient coil 220 may be composed of two coils, and a gradient magnetic field is formed between the two coils. In some cases, a single coil may also be used as the gradient coil 220 and be used to generate a gradient magnetic field.

[0048] The sample holder 110 is used to mount the object to be measured or to calibrate the coil. Figure 1 , Figure 2 A sample fixing position 120 may be provided on the sample rod 110 , and a corresponding sample holder or mounting holder may be provided at the sample fixing position 120 to mount and fix the object to be measured or the calibration coil.

[0049] The calibration device is used to calibrate the gradient magnetic field. As for the specific form of the calibration device, at least the current of the gradient coil 220 can be adjusted or controlled; the calibration device can be a component or a combination of multiple components, and the specific form is not limited here.

[0050] The vibration detection device is used to detect the vibration of at least one of the object to be measured, the calibration coil, and the sample rod 110. Figure 1, shows a feasible implementation, wherein the vibration detection device is a laser vibration measurement device 310, which irradiates the sample fixing position 120 of the sample rod 110 with detection light to detect the vibration of at least one of the object to be measured, the calibration coil, and the sample rod 110. In addition, a reflector can be set at the sample fixing position 120 of the sample rod 110 to further improve the detection accuracy at the sample fixing position 120. Please refer to Figure 2 , shows another feasible implementation, wherein the vibration detection device is a piezoelectric vibration measuring device 140, and the sample rod 110 is connected to the corresponding fixing part through the piezoelectric vibration measuring device 140, so as to detect the vibration of the sample fixing position 120 of the sample rod 110 through the piezoelectric vibration measuring device 140.

[0051] The gradient coil 220 responds to the signal of the calibration device, and the calibration device responds to the current signal of the gradient coil 220, the current signal of the calibration coil, and the output signal of the vibration detection device; the calibration device is constructed in a form capable of executing the aforementioned alternating gradient magnetometer calibration method. The calibration device processes the current signal of the gradient coil 220, the current signal of the calibration coil, and the output signal of the vibration detection device to generate a corresponding control signal or control current through the aforementioned alternating gradient magnetometer calibration method, and transmits the control signal or control current to the gradient coil 220 to achieve calibration, so as to use the calibrated gradient coil 220 to detect the object to be measured, thereby improving the detection accuracy of the equipment.

[0052] See also Figure 1 , Figure 2 , showing a feasible implementation of an alternating gradient magnetometer. The gradient coil 220 generates a gradient magnetic field, and the sample rod 110 is used to place the object to be measured or the calibration coil disposed at the sample fixing position 120 at a preset position in the gradient magnetic field. In some cases, in order to adjust the position of the sample fixing position 120 in the gradient magnetic field, the sample rod 110 can be fixed to the moving end of the translation stage 150, and the translation stage 150 can be fixed to the corresponding fixing plate 430, so as to realize the installation and position adjustment of the sample rod 110.

[0053] In some cases, a bias magnetic field generating device 210 may be further provided to further superimpose a bias magnetic field on the basis of the gradient magnetic field to further meet corresponding detection requirements.

[0054] See also Figure 1 , Figure 2, the gradient coil 220 can be mounted on the first fixing plate 410, the sample rod 110 can be mounted on the second fixing plate 430, and a bracket 420 can be arranged between the first fixing plate 410 and the second fixing plate 430 to connect and fix the first fixing plate 410 and the second fixing plate 430, so as to achieve the installation of the sample rod 110 and the gradient coil 220. In some cases, the gradient coil 220 may vibrate when generating an alternating gradient magnetic field. Accordingly, a corresponding vibration isolation component can be arranged on the bracket 420 to isolate the vibration between the first fixing plate 410 and the second fixing plate 430 to a certain extent.

[0055] The present invention also provides a computer storage medium, which is used to store a program, wherein when the program is running, the device where the computer storage medium is located is controlled to execute the aforementioned alternating gradient magnetometer calibration method.

[0056] The present invention also provides an electronic device, comprising a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to execute the aforementioned alternating gradient magnetometer calibration method through the computer program.

[0057] The above shows and describes the basic principles, main features and advantages of the present invention, so the above is only an embodiment of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments, and the above embodiments and descriptions only describe the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention also includes various equivalent changes and improvements, which will fall within the scope of the present invention to be protected.

Claims

1. A method for calibrating an alternating gradient magnetometer, characterized in that: include: Setting a calibration coil at a sample fixing position of the sample rod; S1: passing a calibration current into the calibration coil and calculating the magnetization intensity of the calibration coil; S2: passing an excitation current into the gradient coil to generate a gradient magnetic field, so that the calibration coil vibrates in the gradient magnetic field; changing the frequency of the excitation current to obtain the resonance amplitude of the calibration coil with the gradient magnetic field; S3: calculating the actual magnetic field gradient of the gradient coil under the excitation current according to the resonance amplitude of the calibration coil and the magnetization intensity of the calibration coil; S4: Calibrate the gradient magnetic field according to the actual magnetic field gradient.

2. The method for calibrating an alternating gradient magnetometer according to claim 1, characterized in that: The S4 further includes: calculating the theoretical magnetic field gradient of the gradient coil according to the excitation current of the gradient coil; and calibrating the gradient magnetic field according to the actual magnetic field gradient and the theoretical magnetic field gradient.

3. The alternating gradient magnetometer calibration method according to claim 2, characterized in that: The S4 includes: The calibration current is changed, and steps S1-S3 are performed multiple times to obtain multiple sets of data pairs of actual magnetic field gradients and theoretical magnetic field gradients; and the mapping relationship between the actual magnetic field gradient and the theoretical magnetic field gradient is calculated based on the data pairs.

4. The alternating gradient magnetometer calibration method according to claim 2, characterized in that: The S4 includes: calculating the difference between the actual magnetic field gradient and the theoretical magnetic field gradient, and if the difference is less than a preset threshold, ending the calibration; otherwise, adjusting the excitation current and performing the S2-S4 again until the difference between the actual magnetic field gradient and the theoretical magnetic field gradient is less than a preset threshold.

5. The alternating gradient magnetometer calibration method according to claim 1, characterized in that: The S4 includes: The excitation current is changed, and steps S1-S3 are performed multiple times to obtain multiple sets of data pairs of excitation current and actual magnetic field gradient; and the mapping relationship between the excitation current and the actual magnetic field gradient is calculated based on the data pairs.

6. The alternating gradient magnetometer calibration method according to claim 1, characterized in that: In S3, a mapping relationship between the resonance amplitude of the calibration coil and the magnetic force exerted on the calibration coil is used as a first mapping relationship, and the magnetic force exerted on the calibration coil is calculated according to the resonance amplitude of the calibration coil and the first mapping relationship; The actual magnetic field gradient of the gradient coil under the excitation current is calculated according to the magnetic force and magnetization intensity of the calibration coil.

7. The alternating gradient magnetometer calibration method according to claim 6, characterized in that: The first mapping relationship also responds to the mass of the calibration coil and the resonant frequency of the calibration coil; S2 also includes obtaining the mass and the resonant frequency of the calibration coil; S3 also includes: determining the first mapping relationship through the mass and the resonant frequency of the calibration coil.

8. The alternating gradient magnetometer calibration method according to claim 6, characterized in that: Passing current into the calibration coil to calculate the magnetization intensity of the calibration coil; using the calibrated gradient coil to generate a known gradient magnetic field, and making the calibration coil vibrate in the known gradient magnetic field to obtain the resonance amplitude of the calibration coil; The magnetic force exerted on the calibration coil is calculated according to the known gradient magnetic field and the magnetization intensity of the calibration coil; at least one of the currents passed through the calibration coil and the calibrated gradient coil is adjusted to obtain multiple sets of fitting data pairs of the magnetic force exerted on the calibration coil and the resonance amplitude; and the first mapping relationship is fitted according to the fitting data pairs.

9. A method for using an alternating gradient magnetometer device, characterized in that: include: A1: Install the calibration coil on the sample rod; A2: passing a calibration current into the calibration coil, turning on the gradient coil, and using the calibration coil to calibrate the gradient magnetic field generated by the gradient coil; A3: Remove the calibration coil and install the object to be measured on the sample rod; A4: Turn on the gradient coil and generate a gradient magnetic field to detect the object under test.

10. An alternating gradient magnetometer device, characterized in that: include: Gradient coils, used to generate gradient magnetic fields; A sample rod for mounting the object to be measured or the calibration coil; a calibration device for calibrating the gradient magnetic field; and a vibration detection device for detecting vibration of at least one of the object to be measured, the calibration coil, and the sample rod; The gradient coil responds to the signal of the calibration device, and the calibration device responds to the current signal of the gradient coil, the current signal of the calibration coil, and the output signal of the vibration detection device; the calibration device is constructed in a form capable of executing the alternating gradient magnetometer calibration method as described in any one of claims 1 to 9.

11. A computer storage medium, characterized in that: The computer storage medium is used to store a program, wherein when the program is executed, the device where the computer storage medium is located is controlled to execute the alternating gradient magnetometer calibration method according to any one of claims 1 to 9.

12. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to execute the alternating gradient magnetometer calibration method according to any one of claims 1 to 9 through the computer program.

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