Sources of beam halo in the Next Linear Collider main linac

One of the factors that limited the performance of the Stanford Linear Collider (SLC) was the number of particles per bunch with large betatron or energy amplitudes. We consider the equivalent problem for the Next Linear Collider (NLC) main X-band linacs. We evaluate the number of large-amplitude particles which can be expected due to scattering processes, wakefields, and magnet nonlinearities. We conclude that the number of particles in the beam halo from these sources can easily be accomodated by the planned post-linac collimation system.