Improvements in or relating to cryostat systems

摘要

Cryostat systems comprise first and second liquid interconnected helium baths, and a magnet structure which is immersed in one of the baths. The liquid helium is cooled by means of a pumped refrigeration means. The present invention replaces the pumped refrigeration means with a pulse tube refrigerator which can be located directly within the two baths. The pulse tube refrigerator has a 'cold finger' having cold and warm ends. The cold end extracts into the bath housing the coil structure and has heat exchange connected thereto. The pulse tube refrigerator can also serve to cool the radiation shields.