Pulse tube coolers for HTS devices

Cryocoolers offer a convenient means of cooling where thermal loads are relatively small, particularly where bath cooling is not required and the load may be attached directly to the cold head. Depending on the type of cooler and number of stages, temperatures of 4 K and below may be reached. Unlike either Gifford-McMahon (G-M) or Stirling coolers, pulse tubes have no active components operating at low temperature, and therefore offer the potential of high reliability together with an absolute minimum of microphonics at the cold station. The simplicity of pulse tubes also means that they could probably be produced at relatively low cost if sufficient demand existed. Applications already being considered include the cooling of processor chips and other semiconductor devices, but pulse tubes obviously hold considerable potential in high temperature superconductor (HTS) device applications.