Electron Cloud in the LHC:
Animated simulation results by Oliver Brüning

In all simulations photo-electrons are produced only during the first bunch passage (with a quantum yield of 1.02). The data then shows the evolution of the electron cloud for the successive passage of 10 LHC bunches, assuming a secondary electron yield of 1.7 and no space charge.

Simulations of the LHC electron cloud dynamics with a magnetic field of 8.4 T

Elliptic vacuum chamber: the electron cloud increases without space charge. LHC type vacuum chamber: the electron cloud does not increase even without space charge. It saturates. Thus, for the case where all bunches produce photoelectrons, the density will grow.

Simulations of the LHC electron cloud dynamics without magnetic field

Elliptic vacuum chamber: the electron cloud decreases without space charge. LHC type vacuum chamber: the electron cloud decreases without space charge.

30/07/1997 Francesco.Ruggiero@cern.ch