Control of dynamic disturbances produced by a pulse tube refrigerator in a vibration-sensitive instrumentation

The increase in use of “dry-cooling” technology, which is slowly replacing the LN2 cooling in vibration-sensitive instrumentation, such as scanning electronic microscopes and superconductive quantum interference devices, motivates the further quieting of the attached cryogenic refrigerators. A pulse tube refrigerator produces some relatively low vibration due to the oscillating gas pressure. However small, this may be excessive for the above mentioned vibration-sensitive instrumentation. Therefore, a customized vibration attenuation interface is proposed, which can effectively control this detrimental vibration. The authors propose a thermally conductive, passive vibration isolator for mounting a vibration-sensitive payload on the cold tip of a refrigerator. An optimal design is reached by incorporating an analytical model and appropriate experimentation. The authors demonstrate the capabilities of a first prototype vibration isolator in attenuating a pulse tube’s vibration down to the background level.