Optical fiber feedback SQUID magnetometer

Journal Article · Fri Mar 31 23:00:00 EST 1989 · IEEE (Institute of Electrical and Electronics Engineers) Transactions on Instrumentation and Measurement; (USA)

DOI:https://doi.org/10.1109/19.192358· OSTI ID:5169747

Naito, S; Sampei, Y; Takahashi, T ^[1]

---

1. Yokogawa Electric Corp., 2-9-32, Nakacho, Musashino-shi, Tokyo 180 (JP)

This paper describes an optical fiber feedback superconducting quantum interference device (SQUID) magnetometer which was developed to improve electromagnetic interference characteristics. The SQUID consists of an RF SQUID probe, an RF amplifier, two multimode fibers, and a SQUID control unit. Phase-locked pulse width modulation (PWM) was used to construct a flux locked loop (FLL) circuit in the SQUID control unit. The operation of the optical fiber feedback SQUID is stable when a common mode voltage of ac 100 V/50 Hz is applied. It has an energy resolution of 1 x 10/sup -28/ J/Hz. This paper also describes the measurement of an auditory evoked field from the human brain in a magnetically shielded room using the fiber feedback SQUID with a gradiometer type pickup coil.

• OSTI ID: 5169747
• Journal Information: IEEE (Institute of Electrical and Electronics Engineers) Transactions on Instrumentation and Measurement; (USA), Journal Name: IEEE (Institute of Electrical and Electronics Engineers) Transactions on Instrumentation and Measurement; (USA) Vol. 38:2; ISSN IEIMA; ISSN 0018-9456
• Country of Publication: United States
• Language: English

Related Subjects

426001* -- Engineering-- Superconducting Devices & Circuits-- (1990-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACOUSTIC MEASUREMENTS
AMPLIFIERS
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
DESIGN
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROMAGNETIC PULSES
ELECTROMAGNETIC RADIATION
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
EQUIPMENT
FEEDBACK
FIBERS
FLUXMETERS
HUMAN POPULATIONS
MAGNETIC FIELDS
MAGNETIC SHIELDING
MAGNETOMETERS
MEASURING INSTRUMENTS
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
MODE LOCKING
NERVOUS SYSTEM
OPTICAL FIBERS
ORGANS
PERFORMANCE
PHYSICAL PROPERTIES
POPULATIONS
PULSES
RADIATIONS
SHIELDING
SQUID DEVICES
SUPERCONDUCTING DEVICES
SUPERCONDUCTIVITY