Impedance matching a Josephson galvanometer by means of a superconducting transformer

Journal of Applied Physics

Volumn 42, Issue 10, 1971, Pages 3859-3865

  Clarke, John ^a,b   Tennant, William E ^a,b   Woody, D ^a,b  

^a UNIVERSITY OF CALIFORNIA   (United States)

^b LAWRENCE BERKELEY NATIONAL LABORATORY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

SUPERCONDUCTING DEVICES;

GALVANOMETERS;

EID: 0015127416     PISSN: 00218979     EISSN: None     Source Type: Journal    
DOI: 10.1063/1.1659697     Document Type: Article

References (20)

1. This estimate is based on the assumption that the best low-noise FET has a noise of about [formula omitted] with a source impedance of [formula omitted]
2. Basic principles of the transformer were mentioned in Ref. 4.
3. We usually used resistance wire (manganin or constantan) rather than copper wire to make connections to the solder bead.
4. Best Slugs we have made could resolve better than [formula omitted]
5. Response of the combined system ([formula omitted] circuit and room-temperature amplifier) to a step-function input is the sum of two exponentials, with time constants [formula omitted] and [formula omitted]
6. It is also interesting to note that for a primary and a secondary to be perfectly coupled ([formula omitted] [formula omitted]), in the absence of screening currents all flux which links one circuit must link the other. Therefore the geometries of the primary and secondary must be exactly superposed—the path taken by the secondary current must be identical to that taken by the primary current.
7. 1% Bi was added to the In to increase the normal-state resistance of the tabs.