Development of Extra Large Ultra-High Vacuum Degassing Station: An Instrumentation Study

We reported the development of the extra-large ultra-high vacuum(UHV) degassing station,dedicated to high temperature baking/degassing of the 650 MHz/800 kW continuous-wave speed regulating tube of Circular Electron Positron Collider(CEPC).The vertical baking/degassing station mainly consisted of a UHV chamber(Φ1600 mm×5000 mm),internal/external pumping units including oil-free dry vacuum pumps,magnetic suspension turbo-molecular pumps and sputter-ion pumps; high-temperature baking hood with six cylindrical sections and independent heating-units,elevator,automatic control units and operation/supporting platform.The UHV degassing station was tested.The results show that the automatic controlled degassing station meets all the stringent design requirements.To be specific,the base pressure was better than 8.0×10^-8 Pa,the continuously adjustable baking temperature covers 25~600℃ range with a uniformity of ±5℃.In addition,the UHV-vacuum system can be rapidly cooled with 80 K nitrogen pumped from liquid nitrogen tank.