Development of 40–80K Linear-Compressor Driven Pulse Tube Cryocoolers

Abstract

Along with the commercialization of HTS devices in fields such as mobile communications, and the development of far infrared devices for space and military applications, there arises a strong demand for compact and reliable cryocoolers working at 40–60K. The pulse tube cryocooler driven by a linear pressure wave generator has the potential to achieve high reliability and very long lifetime because of the absence of moving parts at low temperature. The ability of this kind of pulse tube cryocooler to achieve efficiencies comparable with Stirling cryocoolers has been theoretically and practically proven^1-3. Hence, pulse tube cryocoolers appear a good choice to meet the abovementioned requirements.

On the basis of our previous work that focused on miniature co-axial, linear-driven pulse tube cryocoolers with a few hundred milliwatts of cooling power at 80K⁴, we are trying to develop a new series of pulse tube cryocoolers working at lower temperatures and with larger cooling powers. The goal is to provide about 200mW at 40K or 1 ∼2 W at 60K, with input power as small as possible. The pressure wave generators are being developed in our laboratory uses a moving coil linear motor supported by flexure springs. Their maximum swept volumes are 2, 4, 5, and 10cm³ Two types of pulse tube cold head configurations, i.e. coaxial and U-shape, have been adopted to fit different applications. The present status of development for these coolers is presented in this paper,