Beam energy spectra in the presence of cell-to-cell phase advance errors

Abstract The parameters of the accelerating structures of linear accelerators have a strong influence on the beam parameters such as the mean energy and the energy spread. One of the most common types the accelerating structures is based on disk loaded waveguides. Imperfections in such structure parameters may be critical for subsequent beam dynamics. We analytically study the influence of the errors of the cell-to-cell phase advance on the beam energy spread and the mean energy on the example of the constant gradient structure. Derived expressions were applied to the case of a large number of accelerating structures, which is relevant for GeV linacs, to obtain accelerated beam parameters in terms of the probabilistic analysis for several values of the injected beam duration.