IONIZATION IN PROTON--He^+(1s, 2s, or 3s)-ION COLLISIONS Thomas G. Winter Department of Physics, Pennsylvania State University, Wilkes-Barre Campus, Lehman, Pennsylvania 18627, U. S. A. Accurate cross sections are being determined primarily for ionization in p-He^+(1s, 2s, or 3s) collisions for proton energies from about 0.3 to 2 MeV using a coupled-Sturmian-pseudostate approach and also the first-Born approximation. These results are being compared with existing Born and continuum-distorted-wave results.