Liquid nitrogen pre-cooled pulse tube refrigerator with low temperature switch valve and its simulation

In this article, a new kind of pulse tube refrigerator with a low temperature switch valve and a liquid nitrogen pre-cooler is introduced. The aim of this design is to eliminate the shortcomings of ordinary regenerators at temperature below 20K. Theoretical analysis shows that it's a promising alternative of ordinary pulse tube refrigerators. However, the experimental results are not good. Possible reasons are given.