Thermal properties of calorimeters with Ti/Au transition-edge sensors on silicon nitride membranes

We are developing X-ray microcalorimeters employing superconducting-transition-edge sensors (TESs) for relatively high operation-temperatures of an 3He cryostat. The TESs are proximity bilayers of Ti and Au. An important thermal parameters, the thermal conductance G, of the microcalorimeters on SiNx membranes was evaluated by a simple method using R–T curves at different bias currents. It has been shown that the G value can be controlled by altering the membrane thickness and size.