
TY  - JOUR
A1  - Balch, Steve 
T1  - The emerging role of helicopter time domain EM systems
JF  - ASEG Extended Abstracts
JO  - ASEG Extended Abstracts
Y1  - 2004
VL  - 2004
IS  - 1
SP  - 1
EP  - 4
KW  - 
UR  - https://doi.org/10.1071/ASEG2004AB005 
N2  - Helicopter time domain electromagnetic (H-TEM) systems are an emerging technology. The ability to integrate the great depth penetration of fixed-wing systems with the spatial resolution and conductance discrimination of helicopter frequency domain systems is an important development for the detection of discrete conductors. H-TEM systems can be configured with multiple receiver coils to make their responses more diagnostic, such as the discrimination of thick from thin conductors. The use of a rigid geometry allows these systems to measure during the transmitter on-time where high conductance targets produce a stronger response. In areas of conductive overburden, it is possible to remove much of the high amplitude response due to surface conductivity from deeper bedrock conductors by subtracting the off-time response from the corresponding on-time response. The resultant profiles are more diagnostic of bedrock conductors than are the late off-time channels from the same system at a lower base frequency. 
ER  -

