A coupled DC SQUID with low 1/f noise

Heikki Seppä, Mikko Kiviranta, Alexandre Satrapinski, Leif Grönberg, Jorma Salmi, Ilkka Suni

Research output: Contribution to journalArticleScientificpeer-review

26 Citations (Scopus)

Abstract

A low-noise coupled DC superconducting quantum interference device (SQUID) especially optimized for low frequency is discussed. Using large Josephson junctions and a low loop inductance the contribution of the critical current fluctuation to 1/f noise can be minimized. To minimize the inductance the Josephson junctions are placed in the center of the washer close to the SQUID loop. A scaled-up copper model of the SQUID and the signal coil is used to analyze the impedance of the SQUID loop affected by the signal coil. An equivalent circuit model describing the effective inductance of the SQUID loop as a function of the frequency is used to design appropriate damping of the resonances. The DC SQUID characteristics are smooth and the noise performance of the SQUID does not markedly suffer from resonances. The contribution of the 1/f noise at 1 Hz is found to be about 5*10-7 φ0 √Hz.
Original languageEnglish
Pages (from-to)1816 - 1819
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Volume3
Issue number1
DOIs
Publication statusPublished - 1993
MoE publication typeA1 Journal article-refereed

Fingerprint

SQUIDs
direct current
interference
inductance
Inductance
Josephson junctions
coils
washers
Washers
Critical currents
equivalent circuits
Equivalent circuits
low noise
Copper
critical current
Damping
damping
impedance
low frequencies
copper

Cite this

Seppä, Heikki ; Kiviranta, Mikko ; Satrapinski, Alexandre ; Grönberg, Leif ; Salmi, Jorma ; Suni, Ilkka. / A coupled DC SQUID with low 1/f noise. In: IEEE Transactions on Applied Superconductivity. 1993 ; Vol. 3, No. 1. pp. 1816 - 1819.
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title = "A coupled DC SQUID with low 1/f noise",
abstract = "A low-noise coupled DC superconducting quantum interference device (SQUID) especially optimized for low frequency is discussed. Using large Josephson junctions and a low loop inductance the contribution of the critical current fluctuation to 1/f noise can be minimized. To minimize the inductance the Josephson junctions are placed in the center of the washer close to the SQUID loop. A scaled-up copper model of the SQUID and the signal coil is used to analyze the impedance of the SQUID loop affected by the signal coil. An equivalent circuit model describing the effective inductance of the SQUID loop as a function of the frequency is used to design appropriate damping of the resonances. The DC SQUID characteristics are smooth and the noise performance of the SQUID does not markedly suffer from resonances. The contribution of the 1/f noise at 1 Hz is found to be about 5*10-7 φ0 √Hz.",
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A coupled DC SQUID with low 1/f noise. / Seppä, Heikki; Kiviranta, Mikko; Satrapinski, Alexandre; Grönberg, Leif; Salmi, Jorma; Suni, Ilkka.

In: IEEE Transactions on Applied Superconductivity, Vol. 3, No. 1, 1993, p. 1816 - 1819.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - A coupled DC SQUID with low 1/f noise

AU - Seppä, Heikki

AU - Kiviranta, Mikko

AU - Satrapinski, Alexandre

AU - Grönberg, Leif

AU - Salmi, Jorma

AU - Suni, Ilkka

N1 - Project code: PUO1042

PY - 1993

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N2 - A low-noise coupled DC superconducting quantum interference device (SQUID) especially optimized for low frequency is discussed. Using large Josephson junctions and a low loop inductance the contribution of the critical current fluctuation to 1/f noise can be minimized. To minimize the inductance the Josephson junctions are placed in the center of the washer close to the SQUID loop. A scaled-up copper model of the SQUID and the signal coil is used to analyze the impedance of the SQUID loop affected by the signal coil. An equivalent circuit model describing the effective inductance of the SQUID loop as a function of the frequency is used to design appropriate damping of the resonances. The DC SQUID characteristics are smooth and the noise performance of the SQUID does not markedly suffer from resonances. The contribution of the 1/f noise at 1 Hz is found to be about 5*10-7 φ0 √Hz.

AB - A low-noise coupled DC superconducting quantum interference device (SQUID) especially optimized for low frequency is discussed. Using large Josephson junctions and a low loop inductance the contribution of the critical current fluctuation to 1/f noise can be minimized. To minimize the inductance the Josephson junctions are placed in the center of the washer close to the SQUID loop. A scaled-up copper model of the SQUID and the signal coil is used to analyze the impedance of the SQUID loop affected by the signal coil. An equivalent circuit model describing the effective inductance of the SQUID loop as a function of the frequency is used to design appropriate damping of the resonances. The DC SQUID characteristics are smooth and the noise performance of the SQUID does not markedly suffer from resonances. The contribution of the 1/f noise at 1 Hz is found to be about 5*10-7 φ0 √Hz.

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DO - 10.1109/77.233329

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JO - IEEE Transactions on Applied Superconductivity

JF - IEEE Transactions on Applied Superconductivity

SN - 1051-8223

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ER -