Cryostat

Claim 1

A cryostat comprising: a hollow cylindrical liquid helium vessel (3) containing a superconductive magnet coil (1) and liquid helium (2); a plurality of cylindrical heat insulating plates (4) enclosing said hollow cylindrical liquid helium vessel (3); a liquid nitrogen vessel (5) located outwardly of one of said plurality of cylindrical heat insulating plates (4) in enclosing relation: a vacuum vessel (9) enclosing said liquid nitrogen vessel (5) and having a-hollow room temperature space section (10# formed substantially in a central portion; and a plurality of rods (16) formed of material of low thermal conductivity for supporting said liquid nitrogen vessel (5) in said vacuum vessel (9) under tension; characterized in that: said liquid helium vessel (3) extends substantially horizontally and has a plurality of shaft-like projections (13) each extending outwardly from one of opposite end walls thereof; said liquid nitrogen vessel (5) extends substantially horizontally and has a plurality of hollow cylindrical portions (14) each formed at one of opposite ends thereof in positions corresponding to said shaft-like projections (13) of the liquid helium vessel (3) so that the shaft-like projections (13) and the hollow cylindrical portions (14) are located concentrically with each other; and a plurality of support structures (15) each composed of a multiple cylinder of small thickness formed of material of low thermal conductivity connecting said shaft-like projections (13) to said hollow cylindrical portions (14), said multiple cylinder including a plurality of cylinders connected to each other alternately at opposite ends and in central portions.