Abstract
Pulse tube cryocooler does not have moving parts in the expander. Therefore, this cryocoolers are low vibration, high reliability and long life. However, the cooling capacity of pulse tube cryocooler is lower than that of Stirling cryocooler. Therefore, an improvement of the cooling capacity is necessary. In this research, the effect of expander shape on cooling capacity has examined experimentally and numerically, using a model pulse tube refrigerator.