Analysis and Simulation of Beam Ion Instability in ILC Damping Ring with Multi-gas Species

Abstract

Ion induced beam instability is one critical issue for the electron damping ring of the International Linear Collider (ILC) due to its ultra small emittance of 2 pm. The beam ion instability for the latest DTC lattice has been studied both analytically and numerically. Different from previous studies, multi-gas species and exact beam filling patterns have been modeled simultaneously in this study. This feature makes the studies more realistic and accurate. The numerical code has been benchmarked with SPEAR3 experimental data and there is a good agreement between the simulation and observations. It uses the optics from MAD and can handle arbitrary beam filling pattern and vacuum. Our analyses agree well with expensive simulations.

A tiger beetle’s pursuit of prey depends on distance

“…The control gain is close to the critical value, τ = k e 1/ , with τ being the time delay. The derivation of the critical value is given in reference [2]. This further suggests that the beetle reorients itself toward the prey in the least amount of time without exciting oscillations.…”