Fermilab, Batavia
IIT, Chicago, Illinois
Illinois Institute of Technology, Chicago, Illinois
The Fermilab Booster beam is exposed to magnet laminations, resulting in impedance effects much larger than resistive wall effects in a beam pipe. We present a calculation of wake functions in laminated magnets, which show large values at distances of the order of a few meters, but decrease quickly to zero beyond that. Therefore, strong in-bunch and nearest-bunch effects are present. We show realistic Synergia simulations of the Booster using these wake functions and space-charge solvers appropriate for the various geometries of the constituent elements of the machine. The simulation of tune shifts is in good agreement with experimental data. We find that wake fields in the Booster magnet laminations strongly increase beam emittance and have the potential to cause significant beam loss.
