NSLS-II Seminar

Ion effects are one of the very high priority issues in the damping ring R&D for the Technical Design Phase of the International Linear Collider (ILC). Ions produced from the processes like collision ionization, tunnel ionization and synchrotron radiation ionization of the residual gas in the vacuum pipe couple the beam motion and cause the two-stream instabilities in the machine. For the low-emittance storage rings with multi bunch operation, like the ILC electron damping ring, the single passage instability so-called fast ion instability is prominent and potentially deleterious to the machines performance. In this talk, ion effect issues are overviewed, followed by a detailed introduction to the simulation study of the fast ion instability in the ILC damping ring. Possible cures are proposed as well. In addition, the latest experimental results on the fast ion instability at KEK ATF damping ring are also presented.