A fast slewing cryostat for small sample in vacuo electrical/optical testing in the range 30 K-500 K

A cold finger vacuum cryostat is described in which a sapphire heat conducting element is used to achieve very fast slew rates for a small sample stage over a wide temperature range with optimal matching to a closed cycle helium refrigerator head. When the set temperature is reached it is maintained with very high stability (±5 mK). The target applications are associated with semiconductor electrical material characterisation measurements which require temperature scanning, e.g., thermally stimulated current, deep level transient spectroscopy, and applications which require annealing followed by rapid transition to lower temperature for measurement.