BEAM DYNAMICS STUDIES OF THE ESS LINAC USING A NEW MULTICELL CAVITY MODEL

The European Spallation Source is designed to deliver 5 MW proton beam power on the target while keeping the beam induced losses below 1 W/m throughout the LINAC. This implies the need of accurate models to correctly describe
the longitudinal beam dynamics within the multi-cell cavities. In all the previous error studies the cells of a multicell cavity were modelled as a sequence of independent gaps and the errors were applied directly on the amplitude of
each cell accelerating field, considered as random variable. In this paper, instead, we present a new detailed analysis of the effect of the error tolerances on the beam dynamics including a new model to calculate the amplitude errors
of the accelerating field in the multi-cell cavities: errors are applied on the geometrical parameters of each cavity; then the accelerating field is calculated solving the Maxwell equations over all the cavity.