High Frequency Coaxial Pulse Tube Microcooler

This paper describes the continued development of a cryocooler which uses a coaxial pulse tube cold head designed for high operating frequencies. This high frequency design results in a small, low mass, fast cool-down pulse tube cryocooler. The cooler’s coaxial pulse tube cold head was optimized to utilize the small swept volume and high resonant frequency of a scaled down version of Northrop Grumman Space Technology’s existing line of flight qualified compressors. It was also thermodynamically and mechanically optimized for rapid cool-down, and it has a very low inherent thermal mass at the cold end. At a reject temperature of 298 K, this cooler can lift 1.3 W at 77 K. This paper describes this cooler’s performance over a range of frequencies up to 144 Hz and discusses the estimated losses.