Heat Dissipation induced by Microvibrations in Low Temperature Systems

Abstract Low temperature detectors operating at sub-Kelvin temperatures and in the FIR or X-ray wavelengths, are a key feature of space missions addressing the science of the universe. The thermal stability of the coldest cooling stage to which they are thermally coupled is crucial to the performance of thermal detectors. This thermal stability could significantly be compromised by the fluctuations of the thermal dissipation due to microvibrations arriving at said cooling stage. The coldest stage is also often only able to provide a few microwatts of cooling power. Thus to not jeopardise available cooling power nor detector performance, both the thermal dissipation due to induced microvibrations and the variations thereof must be minimised. This article discusses dissipation induced by microvibrations in a gas-gap heat switch, a common elementary device in space cryogenics and ubiquitous in sub-Kelvin applications. The heat switch is instrumented and vibrated at 1.2 K. Dissipation levels of several microwatts for several millig of mechanical excitation are observed.