Multistage pulse tubes Original Research Article

In this paper we address the question of when and how multistaging in pulse-tube refrigerators improves the performance. A two-stage pulse-tube refrigerator is treated as an example. In order to avoid complicated mathematical or numerical calculations we assume that the only irreversible process in the regenerator is heat conduction and that the average enthalpy flow in the regenerator is zero. We derive analytical expressions for the position of the first stage connection to the regenerator in the case of maximum cooling power and in the case of the minimum temperature.