The CEBAF cryogenic system

The CEBAF (Continuous Electron Beam Accelerator Facility) superconducting linear accelerator incorporates cryogenic refrigeration equipment at three locations within the site: the Central Helium Liquefier (CHF), located in the center of the accelerator; the experimental end station refrigerator; and the test laboratory refrigerator located in the Cryogenic Test Facility (CTF) adjacent to the test laboratory. The CEBAF cryogenic system provides 2-K refrigeration to the linacs of the accelerator and test laboratory and 4.5-K refrigeration for the end station experimental halls. The CHF and the test laboratory systems produce 45-K supercritical gaseous helium for shield refrigeration. Liquid nitrogen shields are also incorporated in the test laboratory and end stations. The status of the CHL and of the CTF are reviewed