Quasi-discretization of the electron continuum emitted in collisions of 0.6 MeV u-1 Au11+ with noble gases

We have measured relative doubly-differential cross sections for electron emission in collisions of 0.6 MeV u-1 Au11+ projectile ions with He, Ne and Ar targets for laboratory electron-detection angles between 17o and 80o and electron energies from 100 eV to well above the classical binary encounter region. We observe that, independent of the target Zt, the electron spectra display three characteristic peak-like structures whose energies are nearly invariant with observation angle. These structures are attributed to the diffraction of quasi-free target electrons in the potential of the projectile. (author)