Düsseldorf 2007 – scientific programme

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A: Fachverband Atomphysik

A 28: Collisions with electrons and ions (jointly with MO)

A 28.3: Talk

Friday, March 23, 2007, 11:15–11:30, 5M

A photoemission source for experiments on electron impact ionization of atoms and molecules — •Vladimir Borovik, Toshiyasu Ichioka, Claus Dieter Schröter, Alexander Dorn, and Joachim Ullrich — Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-67119 Heidelberg, Germany

The investigation of single and multiple ionization of atoms by electron impact allows insight into the dynamics of fundamental few-body quantum systems. In the past we have performed these studies combining a standard thermo-cathode electron beam source with a Reaction Microscope (see, e.g., Dürr et al., PRL 96, 243202). In future we aim to improve the electron beam quality concerning the energy definition and timing structure. We therefore have built a photoemission source based on a semiconductor cathode with negative electron affinity (NEA). The design, the preparation procedure of the GaAs crystal and the resulting beam properties will be presented.