1. Some results on the LHC multibunch modes at 7 TeV/c
N. Mounet and E. Métral
From Sacherer theory with the dipolar impedance (= the right impedance to put in a stability diagram) and synchrotron mode m=0, using a complete 25ns filling (3564 bunches), zero chromaticity and nominal LHC design parameters.
N. Mounet and E. Métral - ICE meeting - 01/09/2010

2. Coupled-bunch modes from the beam screens only w. r
Coupled-bunch modes from the beam screens only w.r.t all the machine elements in the model (Collimators + MBWs/MQWs magnets + beam screens + warm pipe + broad band)
In horizontal, beam screens = 55% of the imaginary tune shift (i.e. -1/rise time), 1% of the real tune shift
But pessimistic model of the beam screens in horizontal (used a factor 2 for the weld, see Carlo Zannini)
N. Mounet and E. Métral - ICE meeting - 01/09/2010

3. Coupled-bunch modes from the beam screens only w. r
Coupled-bunch modes from the beam screens only w.r.t all the machine elements in the model (Collimators + MBWs/MQWs magnets + beam screens + warm pipe + broad band)
In vertical, beam screens = 49% of the imaginary tune shift (i.e. -1/rise time), 1% of the real tune shift
N. Mounet and E. Métral - ICE meeting - 01/09/2010

4. Coupled-bunch modes from all the machine elements in the model: effect of the bunch length
For the real tune shift, dependence in power law with a exponent of ~ -0.4
N. Mounet and E. Métral - ICE meeting - 01/09/2010

5. Coupled-bunch modes from all the machine elements in the model: effect of the bunch length
For the imaginary tune shift (= -1/rise time), small linear dependence
For the real tune shift, power law with a exponent of ~ -0.4
N. Mounet and E. Métral - ICE meeting - 01/09/2010