Low Temperature High Frequency Pulse Tube Cooler Using Precooling

Abstract

A low-temperature stage pulse tube cooler is under development at CEA-SBT in partnership with Air Liquide (AL/DTA). This stage is designed to operate from an 80 K heat sink and to provide cooling power at 30 K. In a first phase, an experimental setup featuring a Gifford McMahon (GM) cooler as the precooling stage has been manufactured. The regenerator of the pulse tube stage includes a heat exchanger thermally coupled to the GM cold tip. The design is such that the temperature of this heat sink can be varied over a wide range of temperatures. A preliminary tuning of this experimental setup has been done. In this case, stainless steel meshes have been used even in the low-temperature area. The first results are encouraging, as a temperature lower than 30 K has already been achieved. Sensitivity to various parameters such as inertance, frequency, filling pressure and heat intercept temperature has been tested. The heat extracted at the intermediate heat exchanger has been measured using a shunt-type technique and is compatible with the use of our large-heat-lift pulse tube for precooling. For space applications, the precooling could be provided by a passive radiator. In order to increase the performance, we have examined the use of a regenerator material with better specific heat capacity in the cold area. Lead plated meshes have been manufactured and initial experimental results are presented. This cooler will provide inputs for the design of an integrated two-stage pulse tube cooler in the future.