Single and double ionization of helium for fast, highly-charged ion-impact - Ullrich, J.; Dorner, R.; Berg, H.; Cocke, C.L.; Euler, J.; Froschauer, K.; Hagmann, S.; Jagutzki, O.; Schmidt-Bocking, H.; Tawara, H.; Unverzagt, M.; Mann, R.; et al. (Elsevier)
Using bare Ne, Ni and Kr projectiles, the ratio R of helium double-to-single ionization cross sections was measured at projectile energies of 80 MeV/u =〈 E"p =〈 1.5 MeV/u (0.39 =〈 ν"p/ c =〈 0.93). For Ne^1^0^+ impact R was observed to become independent of ν"p for ν"p / c 0.73, indicating that the high-velocity limit for one-step double ionization (''shake-off'' limit) has been reached for the first time for highly charged ions. Exploiting recoil-ion momentum spectroscopy (RIMS), first results for R, differential in the recoil-ion transverse momentum p"R, are presented for 10 MeV C^5^+ impact. Detailed investigation of the ionization collision dynamics indicates that p"R is reasonably related to the internuclear impact parameter b. This enables comparison of the experimental data with results of b-dependent ab initio calculations.
http://dx.doi.org/10.1016/0168-583X(94)95238-8
Keywords: U