Abstract
Absolute cross sections for single and double ionization of helium have been measured for highly charged (24 {<=} q {<=} 92) and fast (3.6 MeV/u {<=} E{sub p} {<=} 1 GeV/u) heavy-ion impact. The ratio of double to single ionization is found to deviate drastically from the prediction of first order theories: In the strong perturbation regime they fall below the scaling of Knudsen et al. (1984) even for 120 MeV/u U{sup 91+} impact, whereas a dramatic increase by a factor of 4 is observed in the regime of low perturbations for 0.5 and 1 GeV/u Kr{sup 36+} impact. At low reduced energies of E{sub p}/q < or approx. 0.5 the single ionization cross sections are in excellent agreement with recent CDW-EIS calculations by Fainstein et al. (1991) and close coupling calculations by Janev et al. (1980). In the entire energy range the experimental data are predicted within 50% by classical calculations of McKenzie et al. (1987). For 3.6 MeV/u and projectile charge states 24 {<=} q {<=} 55 the cross sections scale slightly weaker than q{sup 2}, as has been observed previously for the regime of strong coupling. (orig.).
Berg, H;
Unverzagt, M;
Spielberger, L;
Euler, J;
Jagutzki, O;
Schmidt-Boecking, H;
[1]
Bernstein, E;
[2]
Hagmann, S;
[1]
Fainstein, P D;
[3]
Ullrich, J;
Schardt, D;
Mann, R;
Mokler, P
- Frankfurt Univ. (Germany). Inst. fuer Kernphysik
- Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)
- Centro Atomico Bariloche (Argentina)
Citation Formats
Berg, H, Unverzagt, M, Spielberger, L, Euler, J, Jagutzki, O, Schmidt-Boecking, H, Bernstein, E, Hagmann, S, Fainstein, P D, Ullrich, J, Schardt, D, Mann, R, and Mokler, P.
Absolute cross sections for helium single and double ionization in collisions with fast, highly charged projectiles.
Germany: N. p.,
1991.
Web.
Berg, H, Unverzagt, M, Spielberger, L, Euler, J, Jagutzki, O, Schmidt-Boecking, H, Bernstein, E, Hagmann, S, Fainstein, P D, Ullrich, J, Schardt, D, Mann, R, & Mokler, P.
Absolute cross sections for helium single and double ionization in collisions with fast, highly charged projectiles.
Germany.
Berg, H, Unverzagt, M, Spielberger, L, Euler, J, Jagutzki, O, Schmidt-Boecking, H, Bernstein, E, Hagmann, S, Fainstein, P D, Ullrich, J, Schardt, D, Mann, R, and Mokler, P.
1991.
"Absolute cross sections for helium single and double ionization in collisions with fast, highly charged projectiles."
Germany.
@misc{etde_10115884,
title = {Absolute cross sections for helium single and double ionization in collisions with fast, highly charged projectiles}
author = {Berg, H, Unverzagt, M, Spielberger, L, Euler, J, Jagutzki, O, Schmidt-Boecking, H, Bernstein, E, Hagmann, S, Fainstein, P D, Ullrich, J, Schardt, D, Mann, R, and Mokler, P}
abstractNote = {Absolute cross sections for single and double ionization of helium have been measured for highly charged (24 {<=} q {<=} 92) and fast (3.6 MeV/u {<=} E{sub p} {<=} 1 GeV/u) heavy-ion impact. The ratio of double to single ionization is found to deviate drastically from the prediction of first order theories: In the strong perturbation regime they fall below the scaling of Knudsen et al. (1984) even for 120 MeV/u U{sup 91+} impact, whereas a dramatic increase by a factor of 4 is observed in the regime of low perturbations for 0.5 and 1 GeV/u Kr{sup 36+} impact. At low reduced energies of E{sub p}/q < or approx. 0.5 the single ionization cross sections are in excellent agreement with recent CDW-EIS calculations by Fainstein et al. (1991) and close coupling calculations by Janev et al. (1980). In the entire energy range the experimental data are predicted within 50% by classical calculations of McKenzie et al. (1987). For 3.6 MeV/u and projectile charge states 24 {<=} q {<=} 55 the cross sections scale slightly weaker than q{sup 2}, as has been observed previously for the regime of strong coupling. (orig.).}
place = {Germany}
year = {1991}
month = {Oct}
}
title = {Absolute cross sections for helium single and double ionization in collisions with fast, highly charged projectiles}
author = {Berg, H, Unverzagt, M, Spielberger, L, Euler, J, Jagutzki, O, Schmidt-Boecking, H, Bernstein, E, Hagmann, S, Fainstein, P D, Ullrich, J, Schardt, D, Mann, R, and Mokler, P}
abstractNote = {Absolute cross sections for single and double ionization of helium have been measured for highly charged (24 {<=} q {<=} 92) and fast (3.6 MeV/u {<=} E{sub p} {<=} 1 GeV/u) heavy-ion impact. The ratio of double to single ionization is found to deviate drastically from the prediction of first order theories: In the strong perturbation regime they fall below the scaling of Knudsen et al. (1984) even for 120 MeV/u U{sup 91+} impact, whereas a dramatic increase by a factor of 4 is observed in the regime of low perturbations for 0.5 and 1 GeV/u Kr{sup 36+} impact. At low reduced energies of E{sub p}/q < or approx. 0.5 the single ionization cross sections are in excellent agreement with recent CDW-EIS calculations by Fainstein et al. (1991) and close coupling calculations by Janev et al. (1980). In the entire energy range the experimental data are predicted within 50% by classical calculations of McKenzie et al. (1987). For 3.6 MeV/u and projectile charge states 24 {<=} q {<=} 55 the cross sections scale slightly weaker than q{sup 2}, as has been observed previously for the regime of strong coupling. (orig.).}
place = {Germany}
year = {1991}
month = {Oct}
}