Superconducting niobium thin-film gradiometer technology program. Final report 4 Jan 82-17 Jan 83
Dc SQUIDs with 2.5 micron square niobium-aluminum oxide-niobium tunnel junctions and titanium resistive shunts have been fabricated. The SQUID inductance was 0.9 nH, and the shunt resistors were approximately 10 ohms. With the SQUIDs operated in a small-signal amplifier mode the minimum white noise of the SQUIDs was measured. Low frequency noise was measured form 0.005 to 2 Hz with the SQUIDs operated in a closed-looped negative-feedback mode. A straight line with a slope of -20 db/decade (1/f frequency dependence) fits the data below 0.5 Hz. This line intersects a horizontal line through the white noise at about 1.6 Hz. A design was completed of a thin-film gradiometer with one-inch square pickup loops, a baseline of 1.1 inches, and a 50-turn input coil, which will fit on a 3-inch diameter silicon wafer. The sensitivity of this gradiometer was predicted. Fabrication of this completely integrated thin-film gradiometer made only of refractory metals should provide an excellent means of predicting the achievable sensitivity and balance of an airborne magnetic gradiometer.
- Research Organization:
- Texas Instruments, Inc., Dallas (USA)
- OSTI ID:
- 5692164
- Report Number(s):
- AD-A-126133/8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CURRENTS
DIRECT CURRENT
ELECTRIC CURRENTS
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
ELECTRODES
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
FABRICATION
FILMS
FLUXMETERS
JUNCTIONS
MAGNETOMETERS
MEASURING INSTRUMENTS
METALS
MICROWAVE EQUIPMENT
NIOBIUM
PHYSICAL PROPERTIES
RESISTORS
SQUID DEVICES
SUPERCONDUCTING DEVICES
SUPERCONDUCTORS
THIN FILMS
TRANSITION ELEMENTS