抄録
The pulse-tube is no solid piston in the expansion space and the pulse-tube is cooled down by that gas does work in the gas. The pulse-tube cryocooler is doesn't need a moving parts in the expansion space and it is an advantage such as a low vibration and high reliability. On the other hand, a pulse-tube cryocooler is different from the solid piston and the cryocooler operating gas often takes an influence due to the change in the environment. When the low temperature part of the expander is in the top from the normal temperature part, natural convection occurs by the influence of the gravity and a cooling capacity decreases greatly. This report is that an examination was done about the efficiency improvement due to the change in the pulse-tube size and the influence which the inclination of the expander on the cooling performance.
