Optical fiber feedback SQUID magnetometer
- 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), Vol. 38:2; ISSN 0018-9456
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BRAIN
MAGNETIC FIELDS
MAGNETOMETERS
DESIGN
OPTICAL FIBERS
SUPERCONDUCTIVITY
SQUID DEVICES
ACOUSTIC MEASUREMENTS
ELECTROMAGNETIC PULSES
ELECTRONIC CIRCUITS
FEEDBACK
HUMAN POPULATIONS
MAGNETIC SHIELDING
MICROWAVE AMPLIFIERS
MODE LOCKING
PERFORMANCE
AMPLIFIERS
BODY
CENTRAL NERVOUS SYSTEM
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
EQUIPMENT
FIBERS
FLUXMETERS
MEASURING INSTRUMENTS
MICROWAVE EQUIPMENT
NERVOUS SYSTEM
ORGANS
PHYSICAL PROPERTIES
POPULATIONS
PULSES
RADIATIONS
SHIELDING
SUPERCONDUCTING DEVICES
426001* - Engineering- Superconducting Devices & Circuits- (1990-)