WO2020051924A1 - Tmr array scanning type rock magnetic detector - Google Patents

Abstract

A TMR array scanning type rock magnetic detector, comprising: a sample positioning system, comprising a three-dimensional sample moving table (10) for placing a rock sample (1), and a sample table controller (20) for adjusting a position of the three-dimensional sample moving table (10); a TMR magnetic field detection system, comprising a TMR probe array (30), and a TMR circuit (40) for driving the TMR probe array (30) to perform magnetic field detection; a magnetizing demagnetization system, comprising a magnetizing demagnetization coil (50) sleeved outside the rock sample (1) and a coil control circuit (60) connected thereto; a data processing control system (70), connected to the TMR circuit (40), the coil control circuit (60), and the sample table controller (20), and configured to receive an input of a user and send a TMR scanning instruction, a magnetization or demagnetization instruction, and a sample table moving instruction, separately. The rock sample (1) can be subjected to magnetic scanning with high magnetic measurement precision and high spatial resolution; moreover, a special magnetizing demagnetization system is provided, and in-situ magnetization and demagnetization can be performed without moving the rock sample (1).

Description

TMR array scanning type rock magnetic detector Technical field

The invention relates to the technical field of magnetic measurement, in particular to a TMR array scanning type rock magnetic detector.

Background technique

Rock contains magnetic minerals, and its magnetic properties are of great significance in geological research. On the one hand, as a special mineral, using its type, particle size, and content information, it can sensitively track a variety of geological and environmental processes, such as mineral generation, migration, and transformation processes (called environmental magnetism). On the other hand, magnetic minerals can be oriented in a geomagnetic field environment. The geomagnetic field at that time is recorded by mechanisms such as thermal remanence (volcanic rocks) and sedimentary remanence (sedimentary rocks or sediments). Information can restore the information of the geomagnetic field at that time (called paleomagnetism). Therefore, the magnetic properties of rocks can be widely used to study geological structure and environmental evolution, petroleum and mineral exploration, deep earth dynamics, sedimentary sequence dating, and archeology.

At present, magnetic field scanning technology is becoming an important research method for magnetic measurement of rock specimens. Paleomagnetic research generally uses superconducting magnetometers, rotating magnetometers, vibrating sample magnetometers, and variable gradient magnetometers to measure the magnetic properties of rock samples. These systems measure the residual magnetism carried by the entire rock sample, which is the superposition of information of all magnetic particles in the sample, but cannot distinguish and extract the information of a single magnetic particle in the sample. With the deepening of the research, in practical applications, we need to know exactly the spatial distribution of magnetic particles and the particle size distribution characteristics of magnetic particles in the sample at the micron level. For example, the distribution pattern of magnetic particles in meteorites carries rich meteorite evolution information; stalagmites and deep-sea manganese stones have lower deposition rates. If it can recognize the magnetism at the micron level, it can construct high-precision environmental evolution information, which will greatly promote the development of related disciplines, which has important scientific significance.

In order to achieve this purpose, the magnetic field scanning technology came into being, which can sensitively measure the magnetic field distribution on the surface of rock samples, and further calculate the distribution characteristics of magnetic particles in the rock. By superposing the magnetic information carried by all magnetic particles at the same level, the residual magnetism of the entire sample can also be calculated statistically. However, the superconducting technology is expensive; the second is limited by the need to equip a low temperature system, and the probe must be separated from the sample by a distance to reduce its spatial resolution.

TMR (TunnelMagnetoResistance) element is a new type of magnetoresistance effect sensor that has begun industrial applications in recent years. It uses the tunnel magnetoresistance effect of magnetic multilayer film materials to induce magnetic fields, which is more than previously discovered and practically applied. AMR (Anisotropic Magneto Resistance) and GMR (Giant Magneto Resistance) elements have greater resistance change rates. TMR element has better temperature stability, higher sensitivity, lower power consumption, better linearity than Hall element, and does not require additional magnetic ring structure; better temperature than AMR element Stability, higher sensitivity, wider linear range, no need for additional set / reset coil structure; better temperature stability, higher sensitivity, lower power consumption, wider Linear range. Based on the above advantages, this sensor has begun to be gradually applied to high-precision technology fields such as information technology, automotive electronics, and biomedicine.

At present, there is a lack of a magnetic magnetic scanning system based on TMR in the prior art. In addition, the general rock magnetic scanning system can only measure the surface magnetism, and does not have the function of in-situ magnetization and demagnetization of the sample. Usually, the sample needs to be taken out of the magnetic shielding room and processed by a special magnetization and demagnetization device. After putting it back into the scanning system, it is difficult to ensure that the rocks are placed in the same position before and after the processing, which is not conducive to comparing the magnetic distribution before and after.

Summary of the Invention

The technical problem to be solved by the present invention is to provide a TMR array scanning type rock magnetic detector for one or more of the defects in the prior art.

In order to solve the above technical problems, the present invention provides a TMR array scanning rock magnetic detector, including:

A sample positioning system includes a three-dimensional sample moving stage for placing a rock specimen, and a sample stage controller for adjusting the position of the three-dimensional sample moving stage; a sample support rod is provided on the three-dimensional sample moving stage;

A TMR magnetic field detection system includes a TMR probe array and a TMR circuit for driving the TMR probe array for magnetic field detection;

Magnetization demagnetization system, including a magnetization demagnetization coil set outside a rock specimen, and a coil control circuit connected thereto;

A data processing control system, which is connected to the TMR circuit, the coil control circuit, and the sample stage controller, and is used to accept user input and send TMR scanning instructions, magnetization or demagnetization instructions, and sample stage movement instructions to the TMR circuit, coil control, respectively. Circuit and sample stage controller.

In the TMR array scanning rock magnetic detector according to the present invention, preferably, the coil control circuit includes:

A pulse power supply, connected to the data processing control system through a data acquisition card, and configured to generate a magnetization pulse current corresponding to a current intensity according to a magnetization instruction issued by the data processing control system;

A signal source, connected to the data processing control system, and configured to generate a sine wave demagnetizing electrical signal of a corresponding frequency according to a demagnetization instruction issued by the data processing control system;

A power amplifier connected to the signal source and configured to amplify the sine wave demagnetized electrical signal generated by the signal source to a corresponding amplitude and output;

A switch is connected to the pulse power source and the power amplifier, and is used to switch the magnetization pulse current or the amplified sine wave demagnetization electric signal to the magnetization demagnetization coil to generate a magnetic field of a predetermined strength, and to perform the function of switching magnetization or demagnetization the goal of.

In the TMR array scanning rock magnetic detector according to the present invention, preferably, the three-dimensional sample moving stage is provided with a stepping motor and a grating scale displacement sensor;

The sample stage controller includes: a motor controller, connected to the data processing control system, for receiving a movement command of the sample stage to generate a motor control signal, and using the position information fed back by the grating scale displacement sensor to implement closed-loop control. The positioning of the sample support rod; a motor driver connected to the motor controller and configured to receive a motor control electrical signal and generate a driving signal to the stepper motor.

In the TMR array scanning rock magnetic detector according to the present invention, preferably, the sample supporting rods are horizontally arranged; there are three stepping motors, which are respectively used to control the sample supporting rods to move in three dimensions. .

In the TMR array scanning type rock magnetic detector according to the present invention, preferably, the length of the sample support rod is 30 cm to 100 cm.

In the TMR array scanning rock magnetic detector according to the present invention, preferably, the three-dimensional sample moving stage and the sample support rod are made of non-magnetic materials.

In the TMR array scanning rock magnetic detector according to the present invention, preferably, the stepping motor is a piezoelectric ceramic ultrasonic motor.

In the TMR array scanning rock magnetic detector according to the present invention, preferably, the TMR probe array, the three-dimensional sample moving stage, and the magnetization demagnetization coil are all placed in a magnetic shielding room.

In the TMR array scanning type rock magnetic detector according to the present invention, preferably, the TMR array scanning type rock magnetic detector further includes a TMR probe array and a sample support rod that are sleeved outside the TMR probe array and the sample support rod during magnetic field detection. Magnetic shielding cylinder; the magnetic shielding chamber is used to shield the internal magnetic field to 100nT and below; the magnetic shielding cylinder is used to shield the internal magnetic field to 10nT and below.

The implementation of the TMR array scanning rock magnetic detector of the present invention has the following beneficial effects: The present invention uses the TMR sensor array and a mobile platform to construct the TMR array scanning rock magnetic detector, which can realize high-precision and high-resolution magnetic scanning of rock specimens. And, a special magnetization demagnetization system is set up to perform in-situ magnetization and demagnetization without moving the rock specimen, which is convenient for comparing the magnetic distribution before and after.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic structural diagram of a TMR array scanning rock magnetic detector according to a first embodiment of the present invention;

2 is a schematic structural diagram of a TMR array scanning rock magnetic detector according to a second embodiment of the present invention;

3 is a schematic diagram of a magnetizing circuit in a TMR array scanning rock magnetic detector according to a second embodiment of the present invention;

4 is a schematic diagram of a demagnetization circuit in a TMR array scanning rock magnetic detector according to a second embodiment of the present invention;

5 is a schematic structural diagram of a magnetization demagnetization coil in a TMR array scanning rock magnetic detector according to a second embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a three-dimensional sample moving stage in a TMR array scanning rock magnetic detector according to the present invention.

detailed description

In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are part of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Please refer to FIG. 1, which is a schematic structural diagram of a TMR array scanning rock magnetic detector according to a first embodiment of the present invention. As shown in FIG. 1, the TMR array scanning rock magnetic detector provided in this embodiment includes at least: a sample positioning system, a TMR magnetic field detection system, a magnetization demagnetization system, and a data processing control system.

The sample positioning system includes a three-dimensional sample moving stage 10 for placing a rock specimen 1, and a sample stage controller 20 for adjusting the position of the three-dimensional sample moving stage 10. The three-dimensional sample moving stage is provided with a sample support rod 11 for placing a rock specimen 1.

The TMR magnetic field detection system includes a TMR probe array 30 and a TMR circuit 40 for driving the TMR probe array 30 for magnetic field detection. The number of TMR sensors in the TMR probe array 30 is n * n.

The magnetization demagnetization system includes a magnetization demagnetization coil 50 sleeved outside the rock specimen 30 and a coil control circuit 60 connected to the magnetization demagnetization coil 50.

The data processing control system 70 is connected to the TMR circuit 40, the coil control circuit 60, and the sample stage controller 20, and is used to accept user input and send TMR scan instructions, magnetization or demagnetization instructions, and sample stage movement instructions to the TMR circuit 40, coil control, respectively. Circuit 60 and sample stage controller 20. The data processing control system 70 can be implemented by, for example, a computer.

Please refer to FIG. 2, which is a schematic structural diagram of a TMR array scanning rock magnetic detector according to a second embodiment of the present invention. As shown in FIG. 2, on the basis of the first embodiment, a specific implementation manner of each system is provided.

The TMR circuit 40 includes a TMR controller 41 and a preamplifier 42. The TMR controller 41 is connected to the data processing control system 70 through a data acquisition card 71, and is configured to receive a TMR scan instruction issued by the data processing control system 70 and generate a TMR control signal. The preamplifier 42 is connected to the TMR controller 41 and is used to amplify and filter the TMR control signal and output a voltage proportional to the magnetic field signal to the TMR probe array 30. Preferably, the TMR probe array 30 in the present invention may be selected from a plurality of TMR sensors and arranged in a matrix. For example, it has a linear measurement range of ± 50Oe, a magnetic field resolution of 2nT / Hz ^1/2 @ 100Hz, and a measurement area of 1 × 2 microns, which is very suitable for scanning weak magnetic samples. This TMR sensor will form a TMR matrix with a total of 16 sensors arranged in a matrix of 4 × 4. The collection of array data can accelerate the measurement speed and achieve spatial resolution on the micrometer scale. The preamplifier 42 can use a power supply with noise attenuation of more than 100 dB to reduce noise.

The coil control circuit 60 includes a pulse power source 61, a signal source 62, a power amplifier 63, and a circuit breaker 64.

The pulse power source 61 is connected to the data processing control system 70 through the data acquisition card 71, and is configured to generate a magnetized pulse current corresponding to the current intensity according to the magnetization instruction issued by the data processing control system 70. Please refer to FIG. 3 in combination, which is a schematic diagram of a magnetizing circuit in a TMR array scanning rock magnetic detector according to a second embodiment of the present invention.

The pulse magnetization of the present invention can use a capacitor discharge pulse magnetization technique. Pulse power supply, the maximum voltage can reach 1500V, charge the internal capacitor balance current, the current is 1-1.5A, the magnetization demagnetizing coil inductance is 32.4mH, the resistance is 1.727ohm, when the capacitance value is 300μF, the capacitor can be charged to 1300V.

The pulse power supply can have four signal interfaces, as shown in the figure:

1) Analog voltage input: used to set the voltage across the capacitor. When the capacitor voltage reaches the set value, the hardware turns off the charging circuit;

2) Analog voltage output: the voltage sensor returns the voltage across the capacitor to the data acquisition card 71;

3) Digital signal input: used for software control switch charging circuit;

4) Digital signal input: used to control the discharge circuit switch.

Four interfaces are connected to the DO, D / A, and A / D interfaces of the data acquisition card.

The signal source 62 is connected to the data processing control system 70, and is configured to generate a sine wave demagnetizing electrical signal with a corresponding frequency according to a demagnetization instruction issued by the data processing control system 70. The power amplifier 63 is connected to the signal source 62 and is used to amplify the sine wave demagnetized electrical signal generated by the signal source 62 to a corresponding amplitude and output. Please refer to FIG. 4 together, which is a schematic diagram of a demagnetization circuit in a TMR array scanning rock magnetic detector according to a second embodiment of the present invention.

In the present invention, the AC demagnetization field uses a signal source 62 and a power amplifier 63 to drive the magnetization demagnetization coil. The signal source 62 is realized by a single-chip microcomputer 622 and an AD9854 chip 621, and the output frequency is 400 Hz, and the voltage amplitude decreases linearly with a sine wave (the magnetic field 200mT is attenuated to 0mT). The single-chip microcomputer 622 communicates with the computer 72 through the RS232 serial port and waits for the computer's demagnetization instruction. The demagnetization instruction set by the PC can change the amplitude and frequency of the output signal, and the output instruction control signal source 62 outputs a signal to the power amplifier for demagnetization. As the power amplifier, an audio power amplifier 631 can be used. For example, the professional amplifier CA20 of commercial sound precision company is used, 8ohm stereo power is 1300w, 4ohm stereo power is 2000w, and 2ohm stereo power is 2600w. Theoretically, a maximum current of 36A can be achieved with a 2ohm load. The maximum voltage calculated by 8ohm can reach 102V. AD9854DDS chip can output sine wave with adjustable frequency, phase and amplitude. 32-bit frequency control word, frequency accuracy can reach 0.0466Hz, 14-bit amplitude control word, 21A maximum current (200mT magnetic field), control accuracy can reach 0.0013A (12.2μT). The frequency of demagnetization is selected as 400Hz. Under the condition of 400Hz, the resistance of the magnetization demagnetization coil 50 is affected by the proximity effect and becomes 2.499ohm. Due to the presence of the inductance, the impedance of the entire load is very large. Use capacitors for tuning. For resistance only, tuning is performed with CBB capacitors in series and parallel. The tuning capacitor is 1.221 μF.

The switch 64 is connected to the pulse power source 61 and the power amplifier 63, and is used to switch the magnetization pulse current or the amplified sine wave demagnetization electric signal to the magnetization demagnetization coil 50 to generate a magnetic field of a predetermined strength and to perform the function of switching the magnetization and demagnetization. purpose.

Although the specific implementations of the pulse power source 61, the signal source 62, and the power amplifier 63 are given above, those skilled in the art can also use other pulse power sources 61, the signal source 62, and the power amplifier 63 that can be applied in the prior art.

Please refer to FIG. 5 in combination, which is a schematic structural diagram of a magnetization demagnetization coil in a TMR array scanning rock magnetic detector according to a second embodiment of the present invention. The measurement of saturated isothermal remanence requires magnetization and demagnetization of the sample, and the TMR probe array is used to measure the remanence signal of the rock specimen. This part mainly includes the design of DC magnetizing magnetic field coil and alternating magnetic field coil, so that the generated magnetic field has high uniformity and resolution. The magnetized demagnetizing coil of the present invention adopts a hollow cylindrical coil structure. As shown in the figure, the inner diameter R1 = 25mm, the outer diameter R2 = 67mm, and the length l = 30mm. The diameter of enameled wire is 1.77mm (copper core 1.68mm). It is wound in 24 layers, each layer is 33 turns, for a total of 792 turns. It can be calculated that when the pulse current I = 105A, B = 1T; when the AC current I = 21A, B = 0.2T. Can meet the requirements of magnetization demagnetization. The manufactured magnetized demagnetizing coil is placed on a coil bobbin, and the coil bobbin may be epoxy material. Rock specimens are placed in the internal cavity of the magnetized demagnetization coil.

The sample positioning system of the present invention can realize three-dimensional precise movement and positioning of a sample. Preferably, the three-dimensional sample moving stage 10 is provided with a stepping motor 13 and a scale displacement sensor 14.

The sample stage controller 20 further includes a motor controller 21 and a motor driver 22. Among them, the motor controller 21 is connected to the data processing control system 70, and is used to receive the sample table movement instruction to generate a motor control signal, and use the position information fed back by the scale displacement sensor 14 to implement closed-loop control of the movement positioning of the rock specimen on the sample support rod 11. . The motor driver 22 is connected to the motor controller 21, and is used for receiving a motor control signal and generating a driving electric signal to the stepping motor 13. The three-dimensional movement and positioning of the three-dimensional sample moving stage 10 are realized by three stepping motors 13 respectively. The stepping motor 13 is preferably a piezoelectric ceramic ultrasonic motor to reduce the residual magnetism of the motor itself. The motor driver of the piezoelectric ceramic ultrasonic motor can be an AB1A driver. When operating in a closed-loop servo system, the motor driver receives an analog signal instruction of +/- 10V from the motor controller and converts the control signal into an AC voltage to drive the motor. The motor controller 21 uses the motion control card DMC 18X2, and the DMC18X2 control card is directly inserted into the PCI card slot of the computer. These two control cards can control 1-4 axes respectively, which can meet the control requirements of the three-dimensional mobile platform . It can provide +/- 10V analog signal command for standard servo system.

The design and production of the rock specimen rack of the present invention requires that the sample support rod 11 be non-magnetic material and is very close to the superconducting receiving coil of the TMR probe array, so as to reduce the attenuation loss of the residual magnetic signal of the rock specimen. In addition, the invention can realize accurate X-Y-Z three-dimensional movement of the sample, and realize the residual magnetic measurement and scanning imaging of the biological sample. Mobile resolution: 20nm, mobile accuracy: 100nm. Preferably, both the three-dimensional sample moving stage 10 and the sample support rod 11 are made of non-magnetic material. Such as ceramics, organic plastics, quartz glass and so on.

The TMR probe array 30, the three-dimensional sample moving stage 10, and the magnetized demagnetizing coil 50 of the present invention are all placed in a magnetic shielding room 9. The invention designs a special magnetic shielding room 9 to provide a zero magnetic field space experimental environment for the entire system, and realize shielding of the ambient static magnetic field and alternating magnetic field. Preferably, a high-permeability material is used to build a square shielded chamber, which can sufficiently accommodate the rock specimen magnetic detection system, experimental samples and experimental operators.

The internal magnetic field of the magnetically shielded chamber 9 constructed by the present invention is a high-standard zero magnetic space below 100 nT and a uniform area lower than 50 nT, which can provide an excellent test environment for the magnetic detection and analyzer of the scanning TMR array rock specimen.

More preferably, the present invention further includes a magnetic shielding tube 8 sleeved outside the TMR probe array 30 and the sample support rod 11 during magnetic field detection. This magnetic shield cylinder 8 is used only when detecting the magnetic field of the rock sample 1, and is withdrawn when it is demagnetized. The above magnetic shielding room 9 is used to shield the internal magnetic field to 100nT and below, which removes the interference of the surrounding environment on the test; magnetic shielding, 8 is used to shield the internal magnetic field to 10nT and below, which can reduce the background magnetic field of the test more low.

Although the sample support rod 11 in FIG. 1 and FIG. 2 is a vertical support rod, the present invention is not limited thereto, and the sample support rod 11 is more preferably a horizontally disposed support rod. Please refer to FIG. 6, which is a schematic structural diagram of a three-dimensional sample moving stage of a TMR array scanning rock magnetic detector according to the present invention. As shown in FIG. 6, the three-dimensional sample moving stage 10 is composed of a three-dimensional moving mechanism, and a horizontal sample supporting rod 12 is provided above. The horizontal sample support rod 12 has a length of 50 cm to 70 cm. The horizontal sample support rod 12 larger than 50cm can reduce the influence of the motor itself and the magnetic field generated during the movement on the measurement.

The TMR array scanning rock magnetic detector of the present invention can achieve the following technical indicators:

1) System sensitivity: 2nT / Hz1 / 2 @ 100Hz;

2) Measurement range: ± 50Oe;

3), single TMR sensitivity: 2-4mV / V / Oe;

4) Magnetization field strength: 0-1T, uniformity ± 2%;

5) Demagnetization intensity: 0-0.3T, uniformity ± 2%;

6) The system spatial resolution reaches 5 × 10-6m;

7) Magnetic shielding index of test area: 0-5 × 10-8T.

In summary, the TMR array scanning rock magnetic detector of the present invention has the following characteristics:

1) In accordance with the magnetic detection and analysis requirements of rock specimens, the present invention provides a scanning rock specimen magnetic detection and analyzer with in-situ magnetization and demagnetization functions. There is no such commercial scanning rock specimen magnetic detection system in the prior art. Generally, various types of magnetometers are used to measure the magnetic moment of the entire sample, and the existing scanning magnetometers do not have the functions of magnetizing and demagnetizing the samples.

2) The present invention proposes to use a TMR probe array to perform two-dimensional scanning on rock specimens, and can use the obtained magnetic signals and the least squares algorithm and deconvolution to realize the measurement of natural remanence and saturated isothermal remanence. Perspective development on data parsing.

The TMR array scanning rock magnetic detector of the present invention can provide a powerful tool for China's geological and geophysical research, not only can it provide new research tools for traditional geosciences such as paleomagnetism, environmental magnetism, etc., but it can also promote biomagnetism The development of such interdisciplinary subjects as meteorite magnetism also has broad application prospects in integrated circuit detection analysis and non-destructive testing of magnetic materials.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than limiting them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still Modifications to the technical solutions described in the foregoing embodiments, or equivalent replacements of some of the technical features thereof; and these modifications or replacements do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A TMR array scanning type rock magnetic detector is characterized in that it includes:

   A sample positioning system includes a three-dimensional sample moving stage for placing a rock specimen, and a sample stage controller for adjusting the position of the three-dimensional sample moving stage; a sample support rod is provided on the three-dimensional sample moving stage;

   A TMR magnetic field detection system includes a TMR probe array and a TMR circuit for driving the TMR probe array for magnetic field detection;

   Magnetization demagnetization system, including a magnetization demagnetization coil set outside a rock specimen, and a coil control circuit connected thereto;

   A data processing control system, which is connected to the TMR circuit, the coil control circuit, and the sample stage controller, and is used to accept user input and send TMR scanning instructions, magnetization or demagnetization instructions, and sample stage movement instructions to the TMR circuit, coil control, respectively. Circuit and sample stage controller.
2. The TMR array scanning rock magnetic detector according to claim 1, wherein the coil control circuit comprises:

   A pulse power supply, connected to the data processing control system through a data acquisition card, and configured to generate a magnetization pulse current corresponding to a current intensity according to a magnetization instruction issued by the data processing control system;

   A signal source, connected to the data processing control system, and configured to generate a sine wave demagnetizing electrical signal of a corresponding frequency according to a demagnetization instruction issued by the data processing control system;

   A power amplifier connected to the signal source and configured to amplify the sine wave demagnetized electrical signal generated by the signal source to a corresponding amplitude and output;

   A switch is connected to the pulse power source and the power amplifier, and is used to switch the magnetization pulse current or the amplified sine wave demagnetization electric signal to the magnetization demagnetization coil to generate a magnetic field of a predetermined strength, and perform the function of switching the magnetization or demagnetization. the goal of.
3. The TMR array scanning rock magnetic detector according to claim 1 or 2, wherein:

   A stepping motor and a grating scale displacement sensor are arranged on the three-dimensional sample moving stage;

   The sample stage controller includes:

   The motor controller is connected to the data processing control system, and is configured to receive a sample stage movement instruction of the data processing control system to generate a motor control signal, and use the position information fed back by the scale displacement sensor to implement closed-loop control of the movement of the sample support rod Positioning

   The motor driver is connected to the motor controller and is configured to receive a motor control signal and generate a driving electric signal to the stepping motor.
4. The TMR array scanning type rock magnetic detector according to claim 3, wherein there are three stepping motors for controlling the movement of the sample support rod in three dimensions, respectively.
5. The TMR array scanning type rock magnetic detector according to claim 4, wherein the sample supporting rod is horizontally arranged.
6. The TMR array scanning type rock magnetic detector according to claim 4, wherein the length of the sample supporting rod is 30 cm to 100 cm.
7. The TMR array scanning type rock magnetic detector according to claim 3, wherein the three-dimensional sample moving stage and the sample supporting rod are both made of non-magnetic material.
8. The TMR array scanning rock magnetic detector according to claim 3, wherein the stepping motor is a piezoelectric ceramic motor.
9. The TMR array scanning rock magnetic detector according to claim 1, wherein the TMR probe array, the three-dimensional sample moving stage, and the magnetization demagnetization coil are all placed in a magnetic shielding room.
10. The TMR array scanning rock magnetic detector according to claim 9, further comprising: Magnetic shield tube

    The magnetic shielding room is used to shield the internal magnetic field to 100nT and below; the magnetic shielding cylinder is used to shield the internal magnetic field to 10nT and below.

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