Thermometry using thermal activation of Josephson junctions at MilliKelvin temperatures

We use the thermal activation of Josephson junctions as a thermometer to investigate heat flow from a hot resistor at milliKelvin temperatures on a silicon chip used for superconducting qubit experiments. The experiments are compared to computer simulations and agree well. These results indicate that on-chip resistors can be used below a certain power level, but not above that level.