Stripper-foil scan studies of the first-turn beam loss mechanism in the LAMPF proton storage ring (PSR)

First-turn beam losses in the LAMPF proton storage ring were measured as a function of the left-right position of the carbon foil used to strip neutral hydrogen atoms to H⁺ for proton injection into the PSR. Two foil thicknesses, 200 and 300 μg/cm² , were tested. Results indicated that first-turn loss is caused predominately by magnetic field stripping of a small fraction of the H ⁰ atoms that pass through the stripper foil without being stripped to protons, and the results were not consistent with a mechanism involving protons originating from atoms in the halo of the neutral beam incident on the stripper foil