Highly scalable readout electronics for large multi-channel dc-SQUID systems

SQUID instruments for biomagnetic diagnostics, radiometry and astrophysics are often equipped with a large number of devices. For systems with more than a few tens of sensors, read-out with an equivalent number of independent components is not an appropriate solution to meet both, technical and financial requirements. In such cases, specifically tailored readout electronics are typically used. In this presentation, the general concept of a new highly scalable and flexible electronics is presented which is intended for operation of up to several 1000 SQUID channels in the linearizing flux locked loop mode. A prototype version of the electronics for the readout of a low-noise biomagnetic system involving 72 SQUID sensors is demonstrated. Measurement results regarding gain, bandwidth, noise, and power consumption will be presented. Finally, we discuss other potential applications in magnetometry and radiation detection with transition edge sensors or metallic magnetic calorimeters.