Emittance Dilution due to Many-Band Long-Range Dipole Wakefields in the International Linear Collider Main Linacs

We investigate the emittance dilution that occurs due to long range wakefields in the ILC (International Linear Collider) [1] L-band linacs. In previous simulations [2] we have focussed upon the largest kick factors (proportional to the transverse fields which transversely kick the beam off axis) for the first three pass-bands. Here we supplement these calculations with an additional four bands. We include seven pass-bands in our simulations with the upper dipole frequencies extending a little higher than 4 GHz. Higher order dipole modes in the first three pass-bands are damped by carefully orientating higher order mode couplers at both ends of each cavity. Here we investigate the impact of upper band modes on the beam dynamics.