Cryostat for HECRAL Superconducting Magnet

Abstract

In order to support the normal operation of HECRAL (Hybrid superconducting Electron Cyclotron Resonance ion source with Advance in Lanzhou) superconducting magnet, a cryostat in the form of immersed in liquid helium was designed, which integrated two two-stage GM (Gifford-McMahon) cryocoolers, helium vessel, thermal shield, outer Dewar, suspension structures, service turret, binary current leads, corresponding monitoring and diagnosis system. The 1st cold head of the two-stage cryocoolers were used to cool the thermal shield and HTS (High Temperature Superconducting) current leads. Enough cooling capacity in the temperature region of 4.2K was supplied by the 2nd cold head to condense the saturated helium vapor evaporated by heat load (including static heat load and dynamic heat load), to realize the “0” liquid helium evaporation operation of the superconducting magnet. The corresponding heat load of the designed cryostat was analyzed, and the WST (Western Superconducting Technologies Co., Ltd.) was commissioned to install the cryostat and carried out cryogenic excitation test. The cryostat is now operated in IMP (Institute of Modern Physics, Chinese Academy of Sciences) and all parts of the magnet and cryostat are working normally, which ensures proper operation of the ion source.