Investigation of DC flow effects on a 4K two-stage pulse tube cryocooler

11th European Conference on Applied Superconductivity

Tsuchiya, A.^1 ; Xu, M.Y.^2

Precision Equipment Group, Sumitomo Heavy Industries, Ltd., 2-1-1, Yato-cho, Nishitokyo-city, Tokyo

188-8585, Japan^1

Technology Research Center, Sumitomo Heavy Industries, Ltd., 2-1-1, Yato-cho, Nishitokyo-city, Tokyo

188-8585, Japan^2

关键词: Cryocoolers;    DC flow;    Dilution refrigerator;    Gas circulation;    Pulse tube cryocoolers;    Stage cooling;    Sumitomo heavy industries;    Ultra low temperatures;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/507/3/032051/pdf
DOI  :  10.1088/1742-6596/507/3/032051

来源: IOP

【 摘 要 】

Sumitomo Heavy Industries, Ltd. (SHI) has been continuously developing 4K GM-type pulse tube cryocoolers for cooling superconducting magnets and pre-cooling ultra-low temperature refrigerators, such as dilution refrigerators, etc. In a double-inlet or a 4-valve GM-type pulse tube cryocooler, there is a gas circulation, called DC flow, generated by the pulse tube, the regenerator and the orifice. The performance of a pulse tube cryocooler is strongly dependent on the rate of such kind of flow. It is possible to improve the performance by optimizing the rate. In order to optimize the rate, a bypass line with a small valve is installed between the warm end of the pulse tube and the low pressure side of the compressor. The second stage cooling capacity at 4.2 K was improved by about 0.25 W after optimization of the rate by adjusting the opening of the valve. The details of the experiment results will be reported in this paper.