Multistage pulse tubes

In this paper we address the question of when and how multistaging in pulse -tube refrigerators improves the performance. A two-stage pulse-tube refrig erator 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 th e regenerator is zero. We derive analytical expressions for the position of the first stage connection to the regenerator in the case of maximum cooli ng power and in the case of the minimum temperature. (C) 2001 Elsevier Scie nce Ltd. All rights reserved.