Abstract
A method to measure the heat transfer from a solid surface to liquid helium in the transient mode with a time resolution in the microsecond range is described. A monofilamentary NbTi/Cu compound conductor 52 μm in diameter is used as a heater by applying a current ≳Ic and, via the temperature dependence of Ic, as thermometer with a response time below 10 μsec. Transient heat transfer can be described by a heat‐flow‐independent transfer coefficient h=5 W/cm2 K below a ’’take‐off’’ time t1. At t1 the heat‐transfer coefficient decreases rapidly due to the onset of film boiling. t1 is related to the heat flow Q by the expression t1Q−2.