%0 Journal Article
%A Mester, A.
%A Zimmermann, Egon
%A Van der Kruk, J.
%A Vereecken, H.
%A Van Waasen, S.
%T Development and drift-analysis of a modular electromagnetic induction system for shallow ground conductivity measurements
%J Measurement science and technology
%V 25
%N 5
%@ 1361-6501
%C Bristol
%I IOP Publ.
%M FZJ-2014-02814
%P 055801
%D 2014
%X Electromagnetic induction (EMI) is used for fast near surface mapping of the electrical conductivity (EC) for a wide range of geophysical applications. Recently, enhanced methods were developed to measure depth-dependent EC by inverting quantitative multi-configuration EMI data, which increases the demand for a suitable multi-channel EMI measurement system. We have designed a novel EMI system that enables the use of modular transmitter/receiver (TX/RX) units, which are connected to a central measurement system and are optimized for flexible setups with coil separations of up to 1.0 m. Each TX/RX-unit contains a coil, which is specifically adjusted for transmitting or receiving magnetic fields. All units enable impedance measurements at the coils, which are used to simulate its electrical circuit and analyze temperature-induced drift effects. A laboratory drift analysis at 8 kHz showed that 88% of the drift in the measured data is due to the change in the electrical transmitter coil resistance. The remaining 12% is due to changes in the transmitter coil inductance and capacitance, the receiver impedance and drifts in the amplification circuit. A measurement under field conditions proved that the new EMI system is able to detect a water-filled swimming pool with 50 mS m−1, using a coil separation of 0.3 m. In addition, the system allows in-field ambient noise spectra measurements in order to select optimal low-noise measurement frequencies
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000334352000041
%R 10.1088/0957-0233/25/5/055801
%U https://juser.fz-juelich.de/record/153151