| Popis: |
The heat load of a superconducting rf cavity is a strong function of the operating frequency and temperature. For CEBAF the optimized choice was 1500 MHz and 2.0 K. Four thousand eight hundred watts of refrigeration at 2.0 K (plus 12,000 W at 45 K) is provided by the Central Helium Liquefier. This is more than an order of magnitude larger than any existing superfluid system; we are, therefore, able to utilize new technologies, e.g., cold compressors with active magnetic bearings. The Central Helium Liquefier system has 1.4 km of transfer lines to distribute the cryogens to the cavities in the linear accelerators. |
