The behaviour of the various gas elements which enter the tube of a pulse t
ube refrigerator from its cold end has been analysed using the method of ch
aracteristics. It is found that, in an orifice pulse tube refrigerator, the
gas elements can be divided into three parts. The specific cooling capacit
y produced by the second part of the gas elements is the largest. If the to
tal mass is fixed, in order to improve the overall cooling capacity of an o
rifice pulse tube refrigerator, the ratio of the gas elements in the second
part should be increased, while those in the first part and the third part
should be decreased. (C) 1999 Elsevier Science Ltd. All rights reserved.