Abstract
A liquid helium temperature fatigue testing system was developed at the National Research Institute for Metals, Tsukuba Laboratories. The system is equipped with a recondenser installed in the test machine cryostat. Helium mist is transferred to the recondenser from the refrigerator, and the evaporated helium gas in the cryostat is recondensed into liquid helium. Thus, the liquid helium level in the cryostat is kept constant without the addition of liquid helium during testing. Continuous operation of about 1000 hours has been achieved with this fatigue testing system.
