THE LOW TEMPERATURE THERMODYNAMIC PROPERTIES OF VANADIUM IN THE SUPERCONDUCTING, NORMAL, AND MIXED STATES.

Abstract not availabl

National Bureau of Standards Reports

Abstract: This document contains the proceedings of the Third Cryocooler Conference, held at the National Bureau of Standards, Boulder, CO, on Sept. 17-18, 1984. About 140 people from 10 countries attended the conference and represented industry, government, and academia. A total of 26 papers were presented orally at the conference and all appear in written form in this document. The emphasis in this conference was on small cryocoolers in the temperature range of 4 - 80 K. Mechanical and non-mechanical types were discussed in the various papers. Applications of these small cryocoolers include the cooling of infrared detectors, cryopumps, small superconducting devices and magnets, and electronic devices

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 application