| 摘要 |
PURPOSE: To rapidly cool a superconducting magnet at a controlled rate to avoid excessive thermal stresses by an initial cooling of the magnet, using a two-stage low-temp. refrigerator provided with a two-stage interface. CONSTITUTION: A pre-cooler has a first stage 11, including a cylindrical heat conductive shell 21 having a spiral groove 23 machined into the outer surface, and a second stage 13 including a solid cylindrical core 31, which is made of a high heat conductive material and has a spiral groove 33 machined into the outer surface. While in a second stage initial cooling using a low-temp. vapor, the radial heat exchange between a magnet and shield gradually pre-cools the magnet uniformly. When the shield is sufficiently cooled, the forced convection boiling occurs in the second stage of the pre-cooler for rapidly cooling the magnet. |
