Performance of Japanese Pulse Tube Coolers for Space Applications

Abstract

We report results from an experimental evaluation of Japanese Stirling-type pulse tube coolers operating at 60–80 K, with potential application to future satellite applications. Three commercial samples were driven under vacuum conditions of below ∼10−2 Pa. The cooling capacities, cooldown times, and the vibration generated by the cold heads and compressors were measured systematically. With room-temperature heat-sink conditions, the cooling capacities at 77K ranged from 2 W to 3.4 W among the three coolers when driven with an effective input power of 100 W. The measured coolers were estimated to be similar to those of US flight coolers used in a previous infrared mission, and the results strongly suggest that Japanese coolers are worth being developed for space use; though, the present input power of 100 W is somewhat large. Displacements of the cold heads during operation depended on the cooler mounting to the base plate and were measured to be ∼3 to 13 µumpp—a value considerably larger than the displacement levels of US flight pulse tube coolers. The vibration of the cold head could be suppressed, even in the present integral-type configuration, if the cold head is placed at the node of vibrations.