Outgassing Test of High Temperature Superconducting (HTS) Power Cable Cryostat

Reduction of outgassing in a high temperature superconducting (HTS) power cable cryostat is very important to achieve a long interval vacuum pumping and to drop the minimum vacuum condition in the cryostat. So, in order to reduce outgassing from the cryostat surface, cleaning and baking are needed processes in manufacturing the cryostat. The outgassing surface of the cable cryostat is larger than the vacuum space of the cable cryostat, therefore the vacuum condition of the cable cryostat degrades quickly at a small outgassing rate. In this paper, to analyze the thermal insulation performance of cable cryostat, we have measured the outgassing rate of the sample HTS power cable cryostat in various structures of thermal insulation (with or without multilayer insulation and filled with liquid nitrogen or without liquid nitrogen) and predicting the trend of the vacuum condition changes by the measured outgassing rate data. A long term outgassing test is performed for three months.