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Optimized Input Output Column

IP.com Disclosure Number: IPCOM000096686D
Original Publication Date: 1963-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Jones, RE: AUTHOR

Abstract

The arrangement in A is for minimizing refrigeration requirements for cooling input/output leads 1 of constant cross sectional area. Leads 1 are connected at lands 2 on cryogenic array supporting substrate 3, immersed in liquid helium bath 4, and to external peripheral equipments not shown. Input/output leads 1 are supported, e.g., on a MYLAR* strip.

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Optimized Input Output Column

The arrangement in A is for minimizing refrigeration requirements for cooling input/output leads 1 of constant cross sectional area. Leads 1 are connected at lands 2 on cryogenic array supporting substrate 3, immersed in liquid helium bath 4, and to external peripheral equipments not shown. Input/output leads 1 are supported, e.g., on a MYLAR* strip.

For a given cryogenic refrigerator construction, temperature stations 5 supplying refrigeration capacity at various temperatures, i.e., 75 degrees K, 35 degrees K, 15 degrees K and 4 degrees K, respectively, are spaced at fixed intervals along refrigerator Dewar wall 6. Total heat Q, i. e., Joule heating generated by a time average current I and conduction heating along input/output leads 1, is dissipated at the various stations 5. The quantity of heat Q dissipated at stations 5 is minimized when lengths of leads 1 between adjacent stations 5 are in proper ratio.

Total heat Q, absorbed at a given station 5 as a function of geometrical factor A/L, is plotted as curve T in B where A and L are crosssectional area and length, respectively, of the section of leads 1 above that station. Curve a depicts Joule heating and curve b depicts conduction heating. The geometrical factor A/L in accordance with minimum total heat Q is given by the quantity I*sqrt(p/2deltaTk) where p is resistivity of the input/output lead material, I is average current along leads 1, delta T is the temperature drop betwe...