Suppression of emittance growth by excited magnet noise with the transverse damper in LHC in simulation and experiment

The LHC transverse dampers initially built to control transverse instabilities are also a good remedy to suppress the oscillations causing emittance growth excited by electro-magnetic noise at the frequencies of betatron sidebands. To prevent the emittance growth excited by the damper itself, it has to have extremely low noise. The paper presents experimental results obtained during the 2010 LHC run and their comparison with simulations of the suppression of these externally excited oscillations and subsequent emittance growth suppression. Recent analysis of emittance growth in LHC shows that there is a missing contribution that cannot be explained by IBS and for which the interplay of the transverse damper with its intrinsic noise and external sources of noise may be the cause. A further reduction of the noise in the damper system is highly desirable. Possible improvements in the damper system to enhance its effectiveness with respect to the suppression of emittance blow-up are also discussed.