Speaker
Dr
Jose Miguel Jimenez
(CERN)
Description
To achieve its nominal performances, the LHC relies on the scrubbing runs to both
improve the dynamic vacuum (beam lifetime) by a vacuum cleaning effect and decrease
the electron cloud induced limitations (heat load and beam instabilities) by a beam
conditioning effect.
An optimum scrubbing run scenario will be presented based on the vacuum cleaning
and beam conditioning results in the SPS together with their applicability to the
LHC and in particular for the role played by the physisorbed gasses and the
magnetic fields.
The interdependence of the scrubbing run scenario with the beam parameters used
during the first 3 years of operation will be presented and the limitations
discussed, in particular the advantages and drawbacks of scrubbing runs at
injection energy. The implications of the deconditioning effect observed when the
machine is not operated with beams will be presented together with the consequences
of a partial warming up of the cold parts during the shutdown.
To follow the evolution of the vacuum cleaning and beam conditioning during the
scrubbing runs, diagnostics are foreseen in the RT and Cold vacuum pilot sectors in
IR4. These diagnostics will be specifically design and operated to provide
information on the beam conditioning levels of the RT and colds sections of the LHC.
Author
Dr
Jose Miguel Jimenez
(CERN)
