Effect of low-frequency ambient magnetic fields on the control unit and rf head of a commercial SQUID magnetometer

Journal Article · Sat Sep 01 00:00:00 EDT 1984 · Rev. Sci. Instrum.; (United States)

DOI:https://doi.org/10.1063/1.1137961· OSTI ID:6807208

Marcus, C M

The control unit and rf head of the SHE model 330X rf SQUID system are shown to be sensitive to ambient ac magnetic fields below 1 Hz, which cause the appearance of false signals corresponding to a magnetometer signal of 10/sup -6/ phi/sub 0/ per gauss of field applied. The control unit shows a sensitivity that is linear with frequency, suggesting that the signal is generated by Faraday induction. In contrast, the rf head response is independent of frequency and shows a strong second-harmonic conversion. This response may be due to the magnetic field sensitivity of the ferrite core inductor in the tuned amplifier of the rf head. These signals induced by ambient fields are a potential source of error in Stanford's Relativity Gyroscope experiment, which uses SQUID's on board a rolling satellite as part of the gyroscope readout system. The extent of the magnetic field sensitivity in these components necessitates the use of additional magnetic shielding aboard the satellite.

• Research Organization: Department of Physics, Stanford University, Stanford, California 94305
• OSTI ID: 6807208
• Journal Information: Rev. Sci. Instrum.; (United States), Vol. 55:9
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
GYROSCOPES
MAGNETIC SHIELDING
MAGNETOMETERS
SQUID DEVICES
SENSITIVITY
ERRORS
GENERAL RELATIVITY THEORY
MAGNETIC FIELDS
NOISE
RESOLUTION
SATELLITES
ELECTRONIC EQUIPMENT
EQUIPMENT
FIELD THEORIES
FLUXMETERS
MEASURING INSTRUMENTS
MICROWAVE EQUIPMENT
SHIELDING
SUPERCONDUCTING DEVICES
420201* - Engineering- Cryogenic Equipment & Devices
640106 - Astrophysics & Cosmology- Cosmology