| 摘要 |
<p>The present invention relates to MRI or NMR systems and, in particular, to a cooling system for a magnet assembly housed in a cryostat incorporating a pulse tube refrigerator (8). The cryostat usually consists of several interior cylindrical or oval-shaped vessels for storing liquids and usually comprises an outer vacuum case, a nitrogen can or a radiation shield instead, and a further radiation shield and the helium vessel (4) housing the superconducting magnet (2). The magnet usually is made of NbTi, Nb3Sn, or some HTC conductor or a combination of both. The present invention uses a pulse tube refrigerator (8), the so-called pulse tube cooler, which essentially comprises an empty tube and a further tube housing the regenerator material for the cooler, which is inserted into the neck tube (6) of the cryosat. <IMAGE></p> |
