A femtoamperemeter based on a superconducting quantum interferometer and a bulk transformer

M.A. Tarasov, A.S. Kalabukhov, S.A. Kovtonyuk, I.L. Lapitskaya, S.A. Gudoshnikov, Mikko Kiviranta, O.V. Snigirev, L.S. Kuzmin, Heikki Seppä

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    Abstract

    A femtoamperemeter based on a superconducting quantum interference device (SQUID) with a planar on-chip gradiometric transformer and an additional volume cryogenic transformer on a toroidal ferromagnetic core is developed, fabricated, and experimentally studied. The conditions for the optimum matching of the SQUID to the signal source are analyzed. It is demonstrated that the conditions for the optimum matching and high coupling coefficient are satisfied in the transformer with a ferromagnetic core. The excess noise introduced by the core is studied experimentally. It is shown that double shielding using superconducting and ferromagnetic shields makes it possible to lower the cutoff frequency of the excess noise to less than 1 kHz.
    Original languageEnglish
    Pages (from-to)1404-1409
    Number of pages6
    JournalJournal of Communications Technology and Electronics
    Volume48
    Issue number12
    Publication statusPublished - 2003
    MoE publication typeA1 Journal article-refereed

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    Cite this

    Tarasov, M. A., Kalabukhov, A. S., Kovtonyuk, S. A., Lapitskaya, I. L., Gudoshnikov, S. A., Kiviranta, M., Snigirev, O. V., Kuzmin, L. S., & Seppä, H. (2003). A femtoamperemeter based on a superconducting quantum interferometer and a bulk transformer. Journal of Communications Technology and Electronics, 48(12), 1404-1409.