Recent low temperature SQUID developments

Magnetometers based on superconducting quantum interference devices (SQUID's) fabricated from low (liquid helium) temperature superconductor materials are currently the most sensitive devices for measuring weak magnetic fields. A major application of low temperature SQUID's is in biomagnetism where multichannel systems with around 100 channels are required. The recent world-wide effort to develop biomagnetic multichannel systems has stimulated both the sophistication of existing SQUID concepts and the development of novel SQUID concepts optimized for biomagnetic applications. The latest SQUID designs are reviewed and their merits are evaluated. Both the noise and the dynamic behavior are discussed and a fair quantitative comparison between the different SQUID concepts is given.<
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