Early Developments and Applications of SQUID Rock Magnetometers.
Abstract
The SQUID rock magnetometer at the University of Pittsburgh was designed by Bill Goree and was operational by 1969. This was only some 7 years after Josephson had published his work predicting the preservation of long range order between two superconductors across a thin insulating barrier: the Josephson junction, whose incredible sensitivity to magnetic flux made the rock magnetometer possible. The intial rock magnetometer used RF SQUIDs. It was designed with an open room temperature access, so that long cores could be passed through the instrument to be measured. Other experiments such as thermal demagnetization, stress effects, or viscosity could also be carried out with continuous observations. Unfortunately, at this time the RF SQUIDs were somewhat unreliable. The intial design had to be abandoned because replacements of SQUIDs required complete disassembly of the instrument, which was costly and time consuming. A standard vertical dewar design was then adopted with the SQUIDs easily accessable in the liquid helium. With the development of more reliable SQUIDs a return to the intial design was undertaken. This intrument with its DC SQUIDs is now used in laboratories all around the world.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFMGP24A..08D
- Keywords:
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- 1594 Instruments and techniques