Vibration Decoupling for Dilution Refrigerators

Due to the cumbersome handling and need for a continuous supply of expensive coolant in conventional wet cryostats, dry cryostats, with pulse-tube coolers doing the pre-cooling at the push of a button, have grown ever more popular. However, these come at the cost of additional vibrations within the cryostat itself. Thus, especially vibration-sensitive applications require pausing the pulse-tube cooler and relying on passive isolation. This is of course not possible for indefinite periods of time.

In this patent-pending system, the sampleholder is hanging freely inside the cryostat, effectively decoupling the two. The connectionto the external mount consists of multiple stages of mechanically damping and thermally insulating components. In order to reach target temperature <10 mK, the support incorporates additional radiation shielding as well as mechanically flexible thermal bridges to select stages of the cryostat. A fully-functional prototype has been in use by the inventors for almost a year supporting several different use cases. Resulting mechanical noise is at least as low as for wet cryostats.

Unlike previous solutions, the invention combines virtually indefinite continuous operation time at constant low temperature with minimal mechanical noise and easy handling – and can be retrofitted in most commercially available cryostats. This makes it making it ideally suited for quantum computing and particularly vibration sensitive measurement applications.

Technology Readiness Level 7: System prototype demonstrated in operational environment