Noise characteristics of a dc SQUID with a resistively shunted inductance. II. Optimum damping

Keiji Enpuku, K. Yoshida, S. Kohjiro

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

Effects of a damping resistance on noise characteristics of a dc SQUID are studied theoretically, where the damping resistance is in shunt with a loop inductance of the SQUID. An analytical expression for the energy resolution of the SQUID is obtained, with which the relation between the damping resistance and the energy resolution is studied in detail. It is shown that an optimum value of the damping resistance exists, which is determined by the tradeoff between the improvement of the transfer function and the additional noise due to the damping resistance. Optimum values of the damping resistance are about twice the shunt resistance of the SQUID and vary slightly with SQUID modulation parameter β. For optimum damping, the energy resolution is improved, compared with the case without the damping resistance. This means that the SQUID with large β can be used without significant degradation of the performance, i.e., the previous restriction of β=1 can be loosened. The analytical results agree quantitatively with numerical ones.

Original languageEnglish
Pages (from-to)4218-4223
Number of pages6
JournalJournal of Applied Physics
Volume60
Issue number12
DOIs
Publication statusPublished - Dec 1 1986

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inductance
damping
shunts
tradeoffs
transfer functions
energy
constrictions
degradation
modulation

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Noise characteristics of a dc SQUID with a resistively shunted inductance. II. Optimum damping. / Enpuku, Keiji; Yoshida, K.; Kohjiro, S.

In: Journal of Applied Physics, Vol. 60, No. 12, 01.12.1986, p. 4218-4223.

Research output: Contribution to journalArticle

Enpuku, Keiji ; Yoshida, K. ; Kohjiro, S. / Noise characteristics of a dc SQUID with a resistively shunted inductance. II. Optimum damping. In: Journal of Applied Physics. 1986 ; Vol. 60, No. 12. pp. 4218-4223.
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