120 Hz pulse tube cryocooler for fast cooldown to 50 K

A pulse tube cryocooler operating at 120 Hz with 3.5 MPa average pressure achieved a no-load temperature of about 49.9 K and a cooldown time to 80 K of 5.5 min. The net refrigeration power at 80 K was 3.35 W with an efficiency of 19.7% of Carnot when referred to input pressure-volume (PV or acoustic) power. Such low temperatures have not been previously achieved for operating frequencies above 100 Hz. The high frequency operation leads to reduced cryocooler volume for a given refrigeration power, which is important to many applications and can enable development of microcryocoolers for microelectromechanical system applications