An improved closed-loop, two-stage pulse-tube refrigerator provides 4 W of cooling power at a temperature of 15 K. The original intended application of this refrigerator is in preventing boiloff of liquid hydrogen from a propellant tank aboard a spacecraft. The basic refrigerator design can also be adapted to terrestrial applications like cooling superconducting electronic devices.

The design operating frequency of this pulse-tube refrigerator is 30 Hz — an order of magnitude greater than the operating frequencies of other pulse-tube refrigerators. The higher frequency makes it possible to design a compressor that is much smaller and lighter, relative to the compressors of lower-frequency pulse-tube refrigerators of similar capacity.

This work was done by W. G. Dean of Dean Applied Technology Co., Inc., for Marshall Space Flight Center.