Recently several approaches have been made to simplify the readout scheme of the standard dc SQUID. A double relaxation oscillation SQUID(DROS) consisting of a hysteretic dc SQUID and a reference junction in series shunted by an inductor and a resistor can provide a very large flux-to-voltage transfer coefficient. Thus, a DROS with direct readout with room temperature dc amplifier can be a good candidate for the next-generation SQUID magnetometer. We report on the development of a 3-channel magnetometer system based on DROS. The DROS is based on Nb/AlO/sub X//Nb Josephson junctions and the main feature of the system is its simple readout electronics.
Lee, Y. H., Kim, J. M., Kwon, H. C., Park, Y. K., Park, J. C., van Duuren, M. J., ... Rogalla, H. (1995). 3-channel double relaxation oscillation SQUID magnetometer system with simple readout electronics. IEEE transactions on applied superconductivity, 5(2), 2156-2159. https://doi.org/10.1109/77.403010