Uniform beam distributions using octupoles

The Gaussian beam profile of the BNL (Brookhaven National Laboratory) 200-MeV H/sup -/ linac beam at the Radiation Effects Facility target location was transformed into a rectangular profile with almost uniform distribution by placing two octupole magnetic elements at particular locations along the beam line. Experimental results of the beam profile projection in the horizontal and vertical planes, with and without octupoles, are presented and compared with third-order calculations. >