Speaker
Paul Cruikshank
Description
Interventions to repair components inside LHC cryostats can only be performed with the system at room temperature. The architecture of the cryogenic and vacuum system permits local warm-up of the 2.8 km arc cryostat. The method, prerequisites, means, constraints, risks and time to locally warm-up a sub-sector are compared to a complete arc warm-up, including the steps to get back to 1.9 K powering. Configuration variants in each arc sector and sub-sector are considered and their impact on the local warm-up procedure. Typical repairs such as diode exchange, helium leak repair and splice consolidation will be presented, including the recent experience of local warm-up in sectors 8-1 and 2-3 to repair DFBA flexible hoses. The necessity and impact of beam vacuum venting during local warm-up will be explained and reviewed.
