Four-quadrant flux quanta counting for wide-range SQUID amplifiers

Mikko Kiviranta (Corresponding Author), Nikolay Beev

    Research output: Contribution to journalArticleScientificpeer-review

    4 Citations (Scopus)

    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.
    Original languageEnglish
    Number of pages5
    JournalSuperconductor Science and Technology
    Volume27
    Issue number7
    DOIs
    Publication statusPublished - 2014
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    quadrants
    SQUIDs
    counting
    amplifiers
    Fluxes
    interference
    analog to digital converters
    quantum counters
    Low noise amplifiers
    low noise
    dynamic range
    Energy dissipation
    Signal to noise ratio
    signal to noise ratios
    dissipation
    Feedback
    Experiments

    Keywords

    • dynamic range
    • fluxon counting
    • SQUIDs
    • superconductivity

    Cite this

    @article{aa3b8a448aa947f3a97fc2f20af91a0c,
    title = "Four-quadrant flux quanta counting for wide-range SQUID amplifiers",
    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.",
    keywords = "dynamic range, fluxon counting, SQUIDs, superconductivity",
    author = "Mikko Kiviranta and Nikolay Beev",
    year = "2014",
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    language = "English",
    volume = "27",
    journal = "Superconductor Science and Technology",
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    Four-quadrant flux quanta counting for wide-range SQUID amplifiers. / Kiviranta, Mikko (Corresponding Author); Beev, Nikolay.

    In: Superconductor Science and Technology, Vol. 27, No. 7, 2014.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Four-quadrant flux quanta counting for wide-range SQUID amplifiers

    AU - Kiviranta, Mikko

    AU - Beev, Nikolay

    PY - 2014

    Y1 - 2014

    N2 - 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.

    AB - 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.

    KW - dynamic range

    KW - fluxon counting

    KW - SQUIDs

    KW - superconductivity

    U2 - 10.1088/0953-2048/27/7/075005

    DO - 10.1088/0953-2048/27/7/075005

    M3 - Article

    VL - 27

    JO - Superconductor Science and Technology

    JF - Superconductor Science and Technology

    SN - 0953-2048

    IS - 7

    ER -