Universal Minimum Heat Leak on Low-Temperature Metallic Electrical Leads

Alan M. Kadin

doi:10.1063/1.2355343

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arXiv · cond-mat/0508697

Universal Minimum Heat Leak on Low-Temperature Metallic Electrical Leads

Alan M. Kadin

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Abstract

Low-temperature electronic systems require electrical leads which have low electrical resistance to provide bias current I without excessive voltage drop V. But proper cryogenic design also requires high thermal resistance to maintain a minimum heat leak Q from the hot temperature T[hot] to the cold temperature T[cold]. By the Wiedemann-Franz law, these requirements are in direct conflict, and the optimal configuration takes a particularly simple universal approximate form for the common case that T[cold] << T[hot]: Q/I = V = 3.6 kT[hot]/e. This is applied here to the cryopackaging of RSFQ superconducting circuits on a 4K cryocooler, but is equally applicable to other cryogenic systems such as a superconducting sensor array at low and ultra-low temperatures.

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Alan M. Kadin. 2007-04-01. Universal Minimum Heat Leak on Low-Temperature Metallic Electrical Leads. https://doi.org/10.1063/1.2355343

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