München 2004 – wissenschaftliches Programm

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A: Atomphysik

A 13: Ion-Atom/Molekuel/Ion-Stoesse

A 13.5: Vortrag

Donnerstag, 25. März 2004, 12:00–12:15, HS 132

Charge-Exchange Cross Sections and the Gas-Solid Effect — •Andrè Fettouhi^1,2, Franck Becker¹, David Boutin¹, Hans Geissel^1,2, Ronja Knöbel², Jan Kurcewicz³, Yuri Litvinov¹, Hidemi Ogawa⁴, Mauricio Portillo¹, Christoph Scheidenberger^1,2, Jens Stadlmann¹, Helmut Weick¹, Martin Winkler^1,2, and Nan Yao^1,2 — ¹Gesellschaft für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany — ²II. Physikalisches Institut, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, D-35392 Gießen, Germany — ³Institute of Experimental Physics, Warsaw University, PL-00-681 Warsaw, Poland — ⁴Department of Physics, Nara Women’s University, Kitauoya-Nishimachi, Nara 630-8506, Japan

It has been known for some time now that the gas-solid effect in charge exchange cross sections arises from differences in the mean free path length. In a gas the mean free path length is usually 1 order of magnitude larger than in solids. With the Fragment Separator at GSI we investigated this effect with Ni²⁷⁺ and Ni²⁸⁺ ions penetrating through various solids and gases at 200 MeV/u. At this energy the ionization cross section is much larger than that of capture, making it possible to study the effect by comparing the fully stripped and H-like Ni ions. The results of the experimental data are presented, along with a short note on the Z_t-dependence of the cross sections.