ausblenden:
Schlagwörter:
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Zusammenfassung:
Higher Order Modes (HOMs) can severely limit the operation of superconducting cavities
in a linear accelerator with high beam current, high duty factor and complex pulse
structure. Therefore, the full HOM spectrum has to be analysed in detail to identify
potentially dangerous modes already during the design phase and to define their damping
requirements.
For this purpose a dedicated beam dynamics simulation code, Simulation of higher
order Mode Dynamics (SMD), focusing on beam-HOM interaction, has been developed in
the frame of this project. SMD allows to analyse the beam behaviour under the presence
of HOMs, taking into account many important effects, such as for example the HOM
frequency spread, beam input jitter, different chopping patterns, as well as klystron and
alignment errors.
SMD is used to investigate in detail into the effects of HOMs in the Superconducting
Proton Linac (SPL) at CERN and in particular their potential to drive beam instabilities
in the longitudinal and transverse direction. Based on these results, HOM damping
requirements for the HOM coupler design are then defined. In addition, the linear accelerators
of the European Spallation Source (ESS) and the Spallation Neutron Source
(SNS) are analysed with respect to HOM impact and the results are compared with the
SPL simulations.
