Uniform Irradiation in a PEFP 100-MeV Beam Line with Octupole Magnets

One of the PEFP (Proton Engineering Frontier Project) 100-MeV beam lines requires a large and uniform irradiation field of +/- 10% uniformity in the target area of 300 mm x 300 mm. We studied the nonlinear optics method by using two octupole magnets in order to achieve a large uniform field at the target. We found that the particles can be uniformly distributed within +/- 10% in a 300 mm x 300 mm irradiation field at the target. We also studied the conditions of the quadrupole and the octupole magnets to meet the requirement of a large and uniform irradiation field.