Thermal Resistance Across the Interstitial Material Kapton MT at Cryogenic Temperatures

Abstract

The present work concentrates on the measurement of the thermal resistance of a copper/Kapton MT/copper junction, in a flat-plate geometry, at cryogenic temperatures. Kapton MT is a polyimide film with alumina filler particles and has a relatively low thermal resistance, but yet a high voltage standoff capability. The thermal resistance consists of two components: thermal contact resistance at the copper/Kapton MT interfaces, and the thermal conduction resistance across the Kapton MT film. The measured thermal resistance indicates that increasing the contact pressure reduces the thermal resistance, to a limit determined by the film conduction resistance. Increasing the contact pressure and the average interface temperature, and decreasing the thickness of the interstitial layer, tends to decrease the thermal resistance.