Kapitza resistance and thermal conductivity of Kapton in superfluid helium Original Research Article

We have determined simultaneously the Kapitza resistance, RK, and the thermal conductivity, κ, of Kapton HN sheets at superfluid helium temperature in the range of 1.4–2.0 K. Five sheets of Kapton with varying thickness from 14 to 130 μm, have been tested. Steady-state measurement of the temperature difference across each sheet as a function of heat flux is achieved. For small temperature difference (10–30 mK) and heat flux density smaller than 30 W m−2, the total thermal resistance of the sheet is determined as a function of sheet thickness and bath temperature. Our method determines with good accuracy the Kapitza resistance, RK=(10540±444)T−3×10−6 K m2 W−1, and the thermal conductivity, κ=[(2.28±0.54)+(2.40±0.32)×T]×10−3 W m−1 K−1. Result obtained for the thermal conductivity is in good agreement with data found in literature and the Kapitza resistance’s evolution with temperature follows the theoretical cubic law.