Test of evaluating performance of Helium recondensing type cryostat with 4 K GM cryocooler

4 K GM 극저온냉동기를 이용한 헬륨 재응축형 극저온용기의 성능 평가시험

The helium recondensing type cryostat with 4 K GM cryocooler is fabricated in order to keep cryogenic state of two saddle type superconducting magnet opposite to each other designed maximum 0.3 T magnetic field, and 1270 mm diameter open bore. The current leads which consist of metal current leads made for brass sheet and HTS current leads made in American Superconductor$^{TM}$ intermediate cool down with cryocooler Thus , the cryocooler for helium recondensing is a 1.5W/4.2 K GM SUMITOMO cryocooler. While superconducting magnet is working of 1600 gauss to 200 A, the cryostat keep constantly the level of liquid helium at 0.05 bar gauge pressure.e.