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LOW-FREQUENCY NOISE REDUCTION IN SQUID MEASUREMENTS USING A LASER-DRIVEN SUPERCONDUCTING SWITCH. 1. DIRECT INPUT CIRCUIT SWITCHING. 2. MODULATED INDUCTANCE SWITCHING.

Author(s) : ANDERSON J. T.

Type of article: Article

Summary

THE AUTHORS DESCRIBE A TECHNIQUE FOR SUBSTANTIALLY DECREASING THE NOISE IN SQUID MEASUREMENT APPLICATIONS WHICH ARE INTRINSICALLY LOW FREQUENCY OR DIRECT CURRENT AND THUS FALL BELOW THE L/F KNEE IN THE SQUID NOISE ENERGY SPECTRUM. THE TECHNIQUE INVOLVES REVERSING THE SQUID INPUT LEADS AT A CHOPPING FREQUENCY OF APPROXIMATELY 100 HERTZ USING LASER-DRIVEN SWITCHES WHICH FORM A DOULOD FOR SUFFICIENTLY LOW NOISE SWITCHING, THE DEMODULATE OUTPUT NO LONGER CONTAINS THE SQUID LOW-FREQUENCY NOISE BUT RATHER NOISE AT THE SQUID WHITE-NOISE FLOOR. FOR APPLICATIONS WHERE THELOSS OF SLEW RATE IS UNACCEPTABLE, THE AUTHORS PRESENT IN THE ARTICLE AN ALTERNATE CHOPPING TECHNIQUE WHICH CAN PRESERVE THE ORIGINAL SQUID SLEW RATE WITH A LOSS IN LOW-FREQUENCY SIGNAL-TO-NOISE ENERGY RATIO OF ABOUT A FACTOR OF 4.

Details

  • Original title: LOW-FREQUENCY NOISE REDUCTION IN SQUID MEASUREMENTS USING A LASER-DRIVEN SUPERCONDUCTING SWITCH. 1. DIRECT INPUT CIRCUIT SWITCHING. 2. MODULATED INDUCTANCE SWITCHING.
  • Record ID : 1991-2010
  • Languages: English
  • Source: Rev. sci. Instrum. - vol. 60 - n. 2
  • Publication date: 1989
  • Document available for consultation in the library of the IIR headquarters only.

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