Performance of Nitrogen Heat Tubes in Cooling Down of Superconducting Magnets

The paper describes the application of nitrogen-filled heat tubes for pre-cooling of the superconducting wiggler with “dry” cryostat (ANKA/CLIC Superconducting multipole wiggler 2015). In our design the first stages of cryo-coolers are connected to the magnet yoke by two heat tubes, which provide high heat transmission rate (up to 100 W per tube) in the temperature range from 300K down to 70K. When the nitrogen inside the tubes reaches its freezing point then the heat transmission becomes broken. The heat tubes allowed us to exclude application of liquid nitrogen from the process of pre-cooling of the magnet.