Field Profile Flattening for Multi-Cell Accelerator
Dr. Art Vetter
Boeing Phantom Works
Introduction to multicell cavity
General first order perturbation theory
Perturbation matrix in terms of cell frequency errors
Field profile perturbations in terms of cell frequency
Finding and correcting the frequency errors that account
for observed profile
Strategy for employing active tuners
Standing wave accelerator structures typically require adjustment of the
resonant frequency of each cell in order to produce a reasonably
uniform excitation profile in the desired accelerating mode. First
order perturbation theory can provide an estimate of the field profile distortions
produced by deviations from the ideal resonant frequency of the cells.
These results can be inverted to allow the frequency errors to be inferred
from the measured excitation profile of a structure. A few iterations
allow the field profile to be made flat to within a percent or two.
Finally, the deployment strategy for active tuners is guided by the results
of the perturbation analysis.