Design of transport lines for uniforming beam distribution with octupoles

The intensity distribution of a typical particle beam is an approximate Gaussian distribution while many applications require the beam to be uniform. Local bright spots on the targets for high-power Gaussian beams create difficult cooling problems and shorten the lifetime of the target. In this paper, we have theoretically studied uniformization of the transverse beam profile using two octupole magnets placed at particular locations in the beam transport line. The details about the requirements on magnet strength and phase advance will be shown. As an example, we take a set of China Spallation Neutron Source parameters to simulate the beam. The simulation result agrees well with theoretical formulas