Tune shifts and spreads due to short and long range beam-beam interaction

Abstract

The performance of existing and proposed collider is often limited by the beam-beam interaction. The tune shift and spread from head-on and long-range beam-beam interactions for both round and flat Gaussain beam have been studied with analysis method in this paper. These formulas are useful for multi-bunch colliders where both short-range and long-range beam-beam interactions should be considered.

Method study of parameter choice for a circular proton–proton collider

“…The spread must be limited to those values that avoid crossing the dangerous resonance in the operation tune space of the machine. This crossing may also produce instabilities in the beam, limiting the performance of the machine (beam lifetime and luminosity) and creating radiation problems in the detectors (beam-halo) [11,12]. To obtain a high beam-beam parameter, with a small effect on the luminosity, and considering the experience gained from experiments at the LHC and Tevatron [13][14][15], the full crossing angle θ c is chosen to provide a beam-beam separation of n s = 10-12 RMS beam sizes for the parasitic crossings [8,16]:…”