An HTS dc SQUID system in competition with induction coils for TEM applications

A superconducting quantum interference device (SQUID) system using high-T-c de SQUID magnetometers setup for geomagnetic prospection is presented. Tn geomagnetic prospection using the transient electromagnetics method the SQU ID system had to compete with conventional induction coils. In measurements above real geological targets the significantly better performance of the SQUID based sensor compared to those coils could be demonstrated. The lower noise of the SQUID system at low frequencies allows measurement of the tra nsients 5-10 times longer, which results in an increase of the investigatio n depth of a factor more than 3. For the same data quality the measurement time can be reduced by a factor of 25-100 compared to coils. (C) 2001 Elsev ier Science B.V. All rights reserved.