C. L. BOHN, K.-Y. NG (Fermilab)
An analytic theory of cumulative multibunch beam breakup in linear colliders is developed. Included is a linear variation of transverse focusing across the bunch train as might be applied, e.g., by chirping the radiofrequency power sources or by using radiofrequency quadrupole magnets. The focusing variation saturates the exponential growth of the beam breakup and establishes an algebraic decay of the transverse bunch displacement versus bunch number. A closed-form expression for the transverse displacement is developed. It is used to quantify the total normalized emittance and thereby isolate the region of parameter space corresponding to high multibunch luminosity. The sensitivity of multibunch beam breakup to variations in accelerator and beam parameters is likewise quantified.
*Work supported by the Universities Research Association, Inc. under contract DE-AC02-76CH00300 with the U.S. Department of Energy.
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