A vibration free cryostat using pulse tube cryocooler

This paper introduces a new vibration free cryostat cooled by liquid helium and a 4 K pulse tube cryocooler. The cryogenic device mounts on the sample cooling station which is cooled by liquid helium The boil off helium is recondensed by the pulse tube cryocooler, thus the cryostat maintains zero boil off There is no mechanical contact between the cryogenic part of the cryocooler and the sample cooling station A bellows is used to isolate the vibration which could transfer from the cryocooler flange to the cryostat flange at the room temperature Any vibrations generated by the operation of the cryocooler are almost entirely isolated from the cryogenic device. The cryostat provides a cooling capacity of 0 65 W at 4.21 K on the sample cooling station while maintaining a vapor pressure of 102 kPa. The sample cooling station has a very stable temperature with oscillations of less than +/-3 mK during all the operations. A cryogenic microwave oscillator has been successfully cooled and operated with the cryostat. (C) 2010 Elsevier Ltd. All rights reserved