Noise study of gradiometer comprised of a Ketchen-type dc-SQUID with additional positive feedback (APF)

Yooichi Takada; K. Kazami; G. Uehara; Hisashi Kado

doi:10.1117/12.181004

2 July 1994 Noise study of gradiometer comprised of a Ketchen-type dc-SQUID with additional positive feedback (APF)

Yooichi Takada, K. Kazami, G. Uehara, Hisashi Kado

Proceedings Volume 2160, Superconductive Devices and Circuits; (1994) https://doi.org/10.1117/12.181004
Event: OE/LASE '94, 1994, Los Angeles, CA, United States

Abstract

We investigated effective flux-to-voltage transfer function and flux noise characteristic corresponding to positive feedback parameter (beta) a on Ketchen-type dc-SQUID with additional positive feedback (APF) by comparing the experimental results with calculated results. The measurement and calculated results for the effective flux-to-voltage transfer function and white flux noise characteristic are in good agreement. We quantitatively obtained the white flux noise characteristic of dc-SQUID (dc-Superconducting Quantum Interference Device) with APF. As (beta) a approaches unity, the flux noise caused by preamplifier voltage noise is decreased and the flux noise caused by the intrinsic flux noise of dc-SQUID with APF is increased. We find that an optimum value of dc-SQUID with APF exists, determined by the trade-off between the flux noise caused by preamplifier voltage-noise and the intrinsic flux noise of dc- SQUID with APF.

Citation Download Citation

Yooichi Takada, K. Kazami, G. Uehara, and Hisashi Kado "Noise study of gradiometer comprised of a Ketchen-type dc-SQUID with additional positive feedback (APF)", Proc. SPIE 2160, Superconductive Devices and Circuits, (2 July 1994); https://doi.org/10.1117/12.181004

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available