Speaker
Description
In accelerators, collimators are used to shape the beam
and protect the machine against damage. They have however
an adverse effect on the beam quality. We present a
trapped-mode analysis of the new collimators for PETRA IV
and their impact on beam dynamics. Wakefield and eigenmode
simulations are used to determine the beam-coupling
impedance of the collimators. From that, the quality factor,
shunt impedance and normalised shunt impedances are extracted.
The results show that higher-order modes make a
significant contribution to the beam-coupling impedance of
the structure. It is shown that geometric modifications can
effectively reduce the beam-coupling impedance. Based on
the found modes, beam stability calculations show stable
behaviour.
| Paper status | No proceeding file submitted. |
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