Research On The Key Technology Of Multi-channel MRS-TEM Joint Instrument

The MRS-TEM joint detection method integrates the Magnetic Resonance Sounding(MRS)method with the advantages of non-invasive,directly detect the groundwater geology information and the Transient Electromagnetic Method(TEM)method with the advantages of large detection depth and directly access to resistivity information,which makes a significant contribution to the groundwater exploration industry in China.However,the MRS-TEM joint detector currently applied to groundwater detection only shares a small number of devices,and does not realize real reuse in technology and hardware,resulting in low transmission power and sharing rate of hardware resource,and the limitation of acquisition channels.It not only causing waste of hardware resources but also limits the research of some data processing methods,such as reference denoising and multi-dimensional joint interpretation.In view of the above problems faced by the current MRS-TEM joint instrument,this paper develops a multi-channel MRS-TEM joint detector based on high-power emission technology.At the same time,some key technologies studied in the paper.On the basis of realizing the sharing of hardware resources,the multi-channel MRS-TEM joint detector improved integration of the instrument.This paper mainly completed the following research work:(1)The basic principles of MRS and TEM methods for detecting groundwater are expounded respectively.The theoretical basis for the joint detection of MRS and TEM is discussed.The flow of MRS-TEM joint interpretation is further introduced.On this basis,the overall structure of the multi-channel MRS-TEM joint instrument is designed,and the functions of each sub-module in the transmitting subsystem and the receiving subsystem are described in detail.(2)The transmitting subsystem of the MRS-TEM joint detector is designed in this paper,the high-power transmitting technology of shared energy storage capacitor and the TEM emission voltage stabilization technology based on Buck circuit are proposed to realize the time-division multiplexing function of the transmitting bridge.At the same time,detailed design instructions for the implementation process of each key technology are carried out.The high-power transmitting subsystem sharing the energy storage capacitor greatly increases the transmission power of the MRS-TEM combined instrument,and the time-division multiplexing function of the transmitting bridge greatly improves the utilization of hardware resources.(3)For the receiving subsystem of the multi-channel MRS-TEM joint instrument designed in this paper,the weak signal conditioning technology and signal acquisition technology of dual-switching are proposed,and the low-noise preamplifier circuit,dual-channel signal conditioning module and data acquisition module are realized.The design further improves the anti-interference ability and integration of the receiving subsystem.(4)The transmitting subsystem and receiving subsystem of MRS-TEM joint instrument designed for this purpose are tested in the laboratory.The effectiveness of the transmitting subsystem was verified by testing the transmitting waveform of the transmitting subsystem in MRS and TEM transmitting modes.Meanwhile,the background noise of the low-noise preamplifier circuit designed in this paper was tested in the electromagnetic shielding room,and the equivalent background noise was only 1nV/?Hz.The field experiment proves the effectiveness multi-channel MRS-TEM joint instrument with the technology of high-power transmission in this paper.In summary,the research in this paper further expands the application of the MRSTEM joint method in groundwater detection,and provides hardware support for the joint interpretation of multi-dimensional data and reference denoising algorithms.