The Development Of High-temperature Superconducting Magnetometer Control Device

Traditionally, magnetic induction coil is utilized as the magnetic field receiver sensor, but it cannot directly measure the magnetic field signal because of the measured low signal noise ratio of induced electromotive force low-frequency signal. Low-frequency signal mainly reflects the deep geological information, but the high-temperature superconducting magnetometer can measure magnetic fields directly. According to electromagnetic theory, good conductor on the underground brings about strong magnetic field for secondary field. However, the magnetic field decay is very slow, i.e. the magnetic field is small, and then the induced electromotive force is also small. Clearly in this case, direct measurement of the magnetic field will improve the signal noise ratio of the data. High-temperature superconducting magnetometer can improve the distinguishability of transient electromagnetic method, making detecting the detailed 1,000-meter-undergrounded geological information possible, which provide new high-tech means in order to find deep metal mining, oil and gas resources, solving the grave problems of the shortage of mineral resources.This article relies on the "863" national high-tech development project sub-project "Aeromagnetic vector (three components) to measure key technology research and prototype development and production" to carry out research work, studying the domestic and international development of high-temperature superconducting magnetometer, analyzing the high-temperature superconducting magnetometer system block diagram, and raising the necessity of the high-temperature superconducting magnetometer control device. The research is based on the working principle of SQUID and High-temperature superconducting magnetometer probe circuit, designed and developed high-temperature superconducting magnetometer measurement and control devices.The MSP430F149 MCU is designed at the core for the high-temperature superconducting magnetometer control device hardware platform, coordinated control of other modules. It is designed and completed eight modules: the power supply module for the device; the scanning field triangle triangle-wave current generator module for the RF SQUID; the signal switching module for triangular wave signal switching and feedback signals; the key module and LCD display module for instrument operation and data set; the data acquisition module for constantly monitoring the voltage; the control module for adjusting optimum operating point for RF SQUID; the communication interface module for uploading the data collected by control system to a computer for data processing and analysis. It is presented in detail the principle of functional circuit module design and parameter index in the paper. The tests showed that the high-temperature superconducting magnetometer control device hardware platform performed normal operation.MSP430F149 is a processor with online programming function. Using a software development platform, IAR Embedded Workbench (V3.42A), in this paper, designing programs using modular design, it completed the programming of function module for the high-temperature superconducting magnetometer control device. The main program modules are the data acquisition module and the control modules. The complete designed high-temperature superconducting magnetometer control devices achieve the following functions:(1) Built-in triangular wave signal source, replacing the original external triangular wave signal source, to achieve system simplicity.(2) The device can automatically load the best operating point of RF SQUID.(3) The device automatically loads the basis of the best operating point can also be manually debug.(4) The device can realize the automatic and manual compensation after the reset.(5) The device can automatically store the optimal operating point to facilitate the turnout next time.Finally, connecting the high-temperature superconducting magnetometer control devices with the superconducting quantum interference device and RF head, open the control unit to adjust the operating point, and signal generator output standard triangular scanning field current. Regulating tuning, RF SQUID bias control level, and the exchange of compensation by the turn buttons, as well as observing with the oscilloscope waveform, to get the best operating point of RF SQUID, it verified the feasibility, versatility and practicality of for the designed high temperature superconducting magnetometer control device.