Abstract :
Physically speaking, the delta function like beam-beam nonlinear forces at interaction points (IPs) act as a sum of delta function nonlinear multipoles. By applying the general theory established previously, in this paper we examine analytically the beam-beam interaction limited dynamic apertures and the corresponding beam lifetimes for both the round and the flat beams. Relations between the beam-beam limited beam lifetimes and the beam-beam tune shifts are established, which show clearly why experimentally one has always a maximum beam-beam tune shift, ξy,max, around 0.045 for e +ecircular colliders, and why one can use round beams to double this value approximately
Keywords :
colliding beam accelerators; electron accelerators; particle beam dynamics; storage rings; synchrotrons; analytical estimation; beam-beam limited dynamic apertures; beam-beam nonlinear forces; beam-beam tune shifts; delta function; flat beams; interaction points; lifetimes; nonlinear multipoles; positron+electron circular colliders; round beams; Apertures; Colliding beam devices; Electron beams; Life estimation; Lifetime estimation; Magnetic heads; Particle beams; Probability; Storage rings; Testing;
