Measured performance parameters of gradiometers with digital output

Conference · Wed Mar 01 04:00:00 EST 1989 · IEEE Trans. Magn.; (United States)

OSTI ID:6043843

Drung, D; Crocoll, E; Herwig, R; Neuhaus, M; Jutzi, W

A planar first order gradiometer and a dc SQUID comparator have been integrated on the same 6x6 mm/sup 2/ chip in the Nb-Nb/sub 2/O/sub 5/-PbInAu technology and operated in a flux-locked loop. Owing to the digital gradiometer output, a very low flux noise of 7x10/sup -7/PHI/sub O//..sqrt..Hz, a coupled noise energy of 34 times Planck's constant h and a gradient noise of 3.8 pT/(m..sqrt..Hz) have been achieved in the white noise region above about 60 Hz. In spite of the very low flux noise, a maximum slew rate of 1.5x10/sup 5/ PHI/sub O//s at a signal frequency of 4 kHz has been measured. A simple modulation scheme has been developed to cancel Josephson junction critical current fluctuations yielding 4.5x10/sup -6/ PHI/sub O//..sqrt..Hz at 0.1 Hz.

• Research Organization: Univ. Karlsruhe, Institut fur Elektrotechnische Grundlagen der Informatik, Hertzstr. 16, D-7500 Karlsruhe 21 (DE)
• OSTI ID: 6043843
• Report Number(s): CONF-880812-
• Conference Information: Journal Name: IEEE Trans. Magn.; (United States) Journal Volume: 25:2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
420201* -- Engineering-- Cryogenic Equipment & Devices
656100 -- Condensed Matter Physics-- Superconductivity
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHALCOGENIDES
CRITICAL CURRENT
CURRENTS
DENSITY
DIGITAL SYSTEMS
ELECTRIC CURRENTS
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
FABRICATION
FLUCTUATIONS
FLUXMETERS
GOLD
INDIUM
JOSEPHSON JUNCTIONS
JUNCTIONS
LEAD
MAGNETIC FLUX
MEASURING INSTRUMENTS
METALS
MICROWAVE EQUIPMENT
NIOBIUM COMPOUNDS
NIOBIUM OXIDES
NOISE POLLUTION
OXIDES
OXYGEN COMPOUNDS
PARAMETRIC ANALYSIS
PHYSICAL PROPERTIES
PLANCK LAW
POLLUTION
REFRACTORY METAL COMPOUNDS
SQUID DEVICES
SUPERCONDUCTING DEVICES
SUPERCONDUCTING JUNCTIONS
TECHNOLOGY ASSESSMENT
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VARIATIONS