Accession Number:

ADA126133

Title:

Superconducting Niobium Thin-Film Gradiometer Technology Program.

Descriptive Note:

Final rept. 4 Jan 82-17 Jan 83,

Corporate Author:

TEXAS INSTRUMENTS INC DALLAS EQUIPMENT GROUP

Personal Author(s):

Report Date:

1983-03-14

Pagination or Media Count:

41.0

Abstract:

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 dbdecade 1f 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.

Subject Categories:

  • Geomagnetism
  • Test Facilities, Equipment and Methods
  • Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE