Transient jitter from injection in storage rings

Abstract

Injection of fresh bunches into a storage ring can induce jitter in the stored bunches. For machines demanding beams of very low emittance and high stability, such as the damping rings of a future linear collider or the storage rings of a super flavor factory, this could be a potential performance limitation. We present an analysis, for the International Linear Collider (ILC) damping rings, of the transverse jitter induced on the extracted bunches from the jitter on the injected bunches, with the coupling between bunches mediated by the resistive-wall wakefield of the vacuum chamber. We find that it is important to include details of the local transverse focusing around the ring. We consider the impact of the finite thickness of the beam pipe wall, and of nonevaporable getter coating on the inside surface: in the parameter regime of the ILC damping rings, we find that the results are only slightly modified compared to an approximation to the resistive-wall wakefield based on a single-layer wall of infinite thickness. The results from our simulations indicate a tight specification on the jitter of the injected bunches. © 2009 The American Physical Society.