The thermal damping of an aerogel resonator in superfluid He-3-B at ultra low temperatures.

We present measurements of the thermal damping of a cylindrical aerogel sample oscillating in superfluid He-3-B in the low temperature regime. The measurements are made at low pressures where the He-3 confined in the aerogel is normal. As in the case of conventional vibrating Wire resonators, the thermal damping arises from quasiparticle collisions at the wire surface and is enhanced by many orders of magnitude by Andreev scattering from the superfluid backflow around the resonator. However, in the case of aerogel, incoming quasiparticles must be absorbed and thermalised within the aerogel before being re-emitted