Performance of a Cryogenic Vacuum System (COLDEX) with a LHC Type Proton Beam

The cold bore experiment (COLDEX) installed in the Super Proton Synchrotron (SPS) has been used to study the performance of a vacuum system operating at cryogenic temperatures in the presence of a Large Hadron Collider (LHC) type proton beam. The ~ 2 m long cryostat, which can be cooled below 3Â K, is fitted with an actively cooled beam screen which can bee temperature-controlled between 5 and 100 K. Molecular desorption and deposited heat load measurements, with or without gas pre-condensation, have been performed. Implications to the LHC design and operation will be discussed.