Performance improvement of a two-stage GM cryocooler by use of Er(Ni_(0.075)Co_(0.925))_2 magnetic regenerator material

摘要

A newly developed magnetic regenerator material Er(Ni_(0.075)Co_(0.925))_2, having high specific heat at temperatures from 10 to 20 K, has been tested inside the second regenerator of a two-stage GM cryocooler. Different working conditions have been examined: four Er(Ni_(0.075)Co_(0.925))_2 /Pb material ratios, three displacer reciprocating speeds, and two cryocooler stroke lengths. In the best working conditions, the experimental results show a cooling power improvement up to 15 percent over the whole temperature range from 10 to 20 K compared to that of the same GM cryocooler employing only lead.