LHC operation in 2011 had a smooth start in March with 75ns beams and only one month later moved to 50ns beam, after a successful dedicated scrubbing run. Several observables, such as pressure rise, heat load in the arcs, beam instability, emittance growth and synchronous phase shift, clearly pointed to the presence of an electron cloud inside the machine during the first days of operation...
We report the observations of beam-beam effects made in MD sessions in 2011.
The results are compared with the expectations and possible implications for the operation in 2012 are discussed.
This presentation will concentrate on the studies carried out on LHC beam instrumentation systems during the 2011 run, the improvements made and the outlook for 2012. It will include an update on the issues resolved since 2010, such as the performance of the BCT systems, and discuss advances in the bunch by bunch measurement capability of many systems. The conclusions will highlight what can...
With thirteen beam induced quenches and numerous Machine Development tests the current knowledge of LHC magnets quench limits still contains a lot of unknowns. Various approaches to determine the quench limits are reviewed and results of the tests are presented. Attempt to reconstruct a coherent picture emerging from these reults is taken. The available methods of computation of the quench...
The Achromatic Telescopic Squeezing (ATS) scheme is a novel squeezing mechanism, which is (almost fully) compatible with the existing hardware of the LHC, and enables both the production and the chromatic correction of very low beta*. The basic principles of the ATS scheme will be reminded together with its basic motivation which is to deliver a very ambitious beta* of 10-15 cm in view of the...
