Mitigating chromatic effects for the transverse focusing of intense charged particle beams

A final focusing scheme designed to minimize chromatic effects is discussed. Solenoids are often used for transverse focusing in accelerator systems that require a charged particle beam with a small focal spot and/or large energy density A sufficiently large spread in axial momentum will reduce the effectiveness of transverse focusing, and result in chromatic effects on the final focal spot. Placing a weaker solenoid upstream of a stronger final focusing solenoid (FFS) mitigates chromatic effects on transverse beam focusing. J.M. Mitrani \textit{et al.}, Nucl. Inst. Meth. Phys. Res. A (2013) http://dx.doi.org/10.1016/j.nima.2013.05.09