Stuttgart 2012 – scientific programme
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A: Fachverband Atomphysik
A 28: Poster: Interaction of matter with ions
A 28.2: Poster
Wednesday, March 14, 2012, 16:30–19:00, Poster.V
Projectile coherence effects in ion-impact induced single ionization of He — •Xincheng Wang1, Micheal Schulz2, Aaron LaForge1, Katharina Schneider1, Aditya Kelkar1, Joachim Ullrich1, Robert Moshammer1, and Daniel Fischer1 — 1Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany — 2Institut für Kernphysik, Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt, Germany
In recent ion-molecule collision experiments the influence of the spatial coherence of the projectile ions on the differential cross sections has been discovered. Even though this effect seems - due to wave-particle duality - rather evident, it has not been considered before: In essentially all theoretical models the projectile ions either have been regarded as plane waves or as classical particles. We investigate the influence of the projectile coherence length in single ionization of helium and have measured the fully differential cross sections in 3MeV proton collisions at the Test Storage Ring (TSR). Here the projectile beam was cooled down using the electron cooling, thus decreasing the beam emittance and thereby increasing the transverse coherence length. The results are in a much better agreement with the theoretical prediction than earlier 100MeV/u C6+ data with smaller coherence length and the same perturbation. These observations suggest, that the earlier observed discrepancies between experiment and theory that have been a puzzle for many years, can be explained considering the coherence properties of the ion beam.