ELECTRON CORRELATION IN THE IONIZATION OF HELIUM BY HIGH-ENERGY PROTONS AND ANTIPROTONS

Following Martin and Salin we discuss how to demonstrate the presence of electron-electron dynamical correlation during the collision of a f ast ion with an atom. Specifically in this paper we calculate proton-h elium and antiproton-helium single- and double-ionization reference cr oss sections when V-ee, the electron-electron interaction, is set to z ero during the collision but retained in the initial and Anal states. We present and critique three ways of obtaining these reference cross sections. Correlation measured in this way seems to be more important for proton projectiles than antiproton projectiles; it is especially n eeded at small impact parameters and for projectile energies below 350 keV.