Berlin 2001 – scientific programme

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A: Atomphysik

A 5: Posters Tuesday (Photoionisation, Multi Photon Processes)

A 5.3: Poster

Tuesday, April 3, 2001, 12:30–15:00, AT3

Cross-section ratio of double to single ionization of Helium — •Andreas Muthig¹, L. Spielberger¹, R. Dörner¹, O. Jagutzki¹, H. Bräuning¹, Th. Weber¹, J. Wang², Y. Qiu³, J. Burgdörfer³, and H. Schmidt-Böcking¹ — ¹Insitut für Kernphysik, Universität Frankfurt, August Euler Str.6, 60486 Frankfurt — ²Department of Physics, Tulane University, New Orleans, Louisiana, 70118-5698 — ³Department of Physics, University of Tennesee 37831-6377

We have measured the ratio of double to single ionization of helium by high energy photons R_C=σ⁺⁺/σ+ at photon energies of 40, 75 and 100 keV. The technique used was recoil ion momentum spectroscopy. The ratio was found to be slightly energy-dependent. The theoretical calculations underline the importance of final-state-correlations which are still not negligible at these photon energies.

Apart from the ratio of total cross sections, the momentum-distribution of the singly-charged He-Ions was measured and is in agreement with the theoretical prediction.