合肥超导托卡马克装置首次致冷

A Primary Cryogenic Test for the Superconducting Tokamak in HEFEI

１９９４年７月１２～２２日期间合肥超导托卡马克装置ＨＴ－７首次低温调试。４Ｋ温区冷重高达１４Ｔ的超导环场磁体经９６ｈ致冷由３００Ｋ降温至９Ｋ，再数小时后降温至４．７Ｋ。磁体用迫流Ｈｅ内冷，用二相Ｈｅ流保冷３昼夜。超导线圈内外侧设置的热辐射屏重约８Ｔ，用液氮致冷，约６０ｈ冷至８０Ｋ，磁体共励磁二次，最大电流达４６５０Ａ，相应的环轴场为２．２Ｔ，超导体的最高场为３．７Ｔ。

A Primary cryogenic test for the superconducting tokamak HT-7 was conducted during the July 12-22 of 1994 in Hefei.It took 96 hour to cooldown the superconducting toroidal magnet to the critical temperature from 300K,and then the magnet temperature reached 4.7K in a few hours.The mass cooled to 4.7K is around 14 tons.The coils and their cases were cooledwith force-flow helium.A cold box supplied two-phase helium to maintain the coils at low temperatwre for three days.The thermal radiation shield of about 8 tons entirely surrounding the toroidal coils was cooled to 80K withliquid nitrogen for 60 hours.The coils were exited two times.The maximumcurrent reached 4650A,which corresponds the fields on the plasma axis of 2.2T and on the superconductor of 3.7 T.