A digital Double Relaxation Oscillation SQUID for particle detector readout

Double Relaxation Oscillation SQUIDs (DROSs) are based on relaxation oscillations that are generated in hysteretic dc SQUIDs by an external L–R shunt. We realized a DROS with the complete flux-locked loop circuitry on one single chip, the Smart DROS. The pulsed output of the Smart DROS enables a digital readout scheme, in which the effective number of voltage pulses across the DROS corresponds to the amount of applied flux. This concept allows high slew rates up to 108 Φ0/s, which enables the Smart DROS to be used for the readout of particle detectors.