Hannover 2003 – scientific programme

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A: Atomphysik

A 2: Multiphotonprozesse 1

A 2.5: Fachvortrag

Monday, March 24, 2003, 12:00–12:15, F128

Atoms in strong X-ray pulses — •Ulf Saalmann — Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden

Ionization of atoms in strong X-ray pulse differs fundamentally from that under optical laser impact. First of all, it starts from the inside because photoionization cross sections at X-ray wavelengths are considerably higher for the inner shells than for the valence shells. Multiple single-photon ionization is possible, in particular because the inner-shell holes created by photoionization are refilled by Auger-like processes. Due to this almost instantaneous refilling of the inner shells they can be ionized many times during the pulse and thus the atoms can be efficiently “pumped dry”. This occurs “inside-out” and is the exact opposite to the ionization mechanism in the visible wavelength regime where the electrons are removed from the outside like shells of an onion. We discuss the relevant time scales of these competing processes.