Low emittance accelerator cavity design to minimize amplification of beam breakup modes

Theoretical analysis and computer simulation have been applied to obtain cavity designs that dramatically reduce cumulative beam breakup amplification for solenoidally focused, high current, relativistic electron beam multiple gap induction accelerators. Specific use is made of low emittance, long gap designs which provide phase cancellation and attendant reduced beam-eigenmode coupling; an effect the usual short gap, or impulse, approximation cannot address. Specific comparison with a standard short gap cavity design for a 50 MeV, 10 kA induction accelerator illustrates the significant improvement in beam breakup suppression that obtains with the low emittance long gap accelerator cavity designs