Abstract
We have studied flux quanta counting in an open loop as a way to implement superconducting quantum interference device (SQUID) amplifiers with a large dynamic range and small power dissipation simultaneously. Good signal-to-noise ratio at all flux values is provided by using two SQUIDs, one yielding sin(ϕ) and the other cos(ϕ) proportional signals. In principle, the lack of feedback lifts the slew rate limitation due to the loop causality present in previously implemented flux quanta counters. Experimental results are shown for up to 180 Φ0 peak-to-peak flux ranges with a 1.5 μΦ0 Hz−1/2 noise floor, dominated by the digitizer noise. The SQUID and low-noise amplifier would allow a 0.07 μΦ0 Hz−1/2 noise floor with a more silent digitizer. Operation up to a 13 Φ0 μs−1 slew rate was demonstrated, but this is not a fundamental limitation. In our experiment, the mismatch between the sin(ϕ) and cos(ϕ) channels limited the practically achievable slew rate.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
