A Mechanical Thermal Switch for Using a Cryostat between 4 and 650 K

Design of a mechanical thermal switch used in a low temperature cryostat is described. In the thermal switch on position, the sample can be cooled to 4 K. In the thermal switch off position, the sample can be maintained at any temperature in the range from 4 to 650 K with cryogenic liquid (liquid helium at low temperatures and liquid nitrogen at higher temperatures) in the cryostat.