700 mm Diameter Cryostats Operating at 1.8 deg K and Atmospheric Pressure

Two devices operational with ten Teslas NbTi coils have been built in order to undertake development programmes in superconducting magnets for fusion and high field research. The inner bore for experiments is in the 300 mm range. The cryostat system is described which enables superfluid helium at 1.8 deg K and atmospheric pressure to be used. Some constructional details concerning the main components are given. The results of the cryogenic tests are finally presented: a fully automated operation at 1.8 deg K with a rather small standard pump and a liquid helium consumption less than 4 l h -- 1 fed at 4.2 deg K. 11 ref.--AA