Mature SQUID-systems and their application

When commercializing SQUID-technology, system aspects predominate, as the SQUID-sensor itself is usually only a minor part of the whole instrumentation. Unfortunately the diversity required by customers and/or by special constraints of the particular application necessitates in all but a few cases customs-made SQUID-systems. The article underlines this fact with examples of recent instrumentation solutions in the fields of ultrasensitive measurement techniques, environmental geophysics, biomagnetism, and biochemical analysis and discusses some additional aspects where an end-user oriented approach directly feeds back into the systems design phase. A common trend in SQUID development required by all applications mentioned is the need for higher slew-rates while keeping the field sensitivity as good as possible.