H-0 (n = 3,4) Stark states produced in the interaction of 800-MeV H- ions with thin foils

The interaction of 800-MeV H- ions with a thin foil produces protons, the g round state and excited states of neutral H-0 atoms, and unstripped H- ions . We investigated the distributions of individual H-0 Stark states within t he n=3 and 4 levels produced by C and Al2O3 foil stripping of H- ions. Foil s of various thicknesses were placed upstream of a magnet with a linearly i ncreasing transverse field along the beam direction producing a motional el ectric field strong enough to ionize H-0 states with n greater than or equa l to 3. We consider three questions: (i) What are the populations of indivi dual H-0 Stark states produced in the interaction of 800-MeV H- ions with t hin C and Al2O3 foils, (ii) how do the relative population distributions ch ange with foil thickness, and (iii) how is the population distribution prod uced in an Al2O3 foil modified when the foil is placed in a magnetic field? A simple qualitative model is presented to explain the major trends. [S105 0-2947(98)02212-4].