Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 36: Poster Session II (Metals; Nanostructures at surfaces; Surface or interface magnetism; Spin-Orbit Interaction at Surfaces; Electron and spin dynamics; Surface dynamics; Methods; Theory and computation of electronic structure)
O 36.97: Poster
Dienstag, 15. März 2011, 18:30–22:00, P4
A time-of-flight electron spectrometer for angle- and time-resolved 2PPE — •Andreas Damm1, Anne Spende1, Jens Güdde1, Achim Czasch2, Ottmar Jagutzki2, Horst Schmidt-Böcking2, and Ulrich Höfer1 — 1Fachbereich Physik, Philipps-Universität, D-35032 Marburg — 2Institut für Kernphysik, Goethe-Universität, D-60438 Frankfurt am Main und RoentDek Handels GmbH, D-65779 Kelkheim
Many studies on surface electron dynamics employing two-photon photoemission (2PPE) would benefit from the ability to map the full two-dimensional surface bandstructure in a single time-resolved experiment. Examples include the study of quasi-elastic electron scattering within electronic surface bands or the extension of 2PPE for the generation of coherently excited electrical currents at surfaces.
Thus, we have developed a position-sensitive time-of-flight spectrometer capable of measuring the kinetic energy as well as the full parallel momentum k||→ of low-energy electrons photoemitted from a surface with a maximum rate of few MHz. Its main components are a field-free drift tube and a delay-line detector for a position-sensitive detection. A variable drift length allows to enhance either the acceptance angle or the energy- and momentum-resolution. The energy resolution for low kinetic energy electrons as typical for 2PPE experiments is better than 10 meV even at the maximum acceptance angle of ±25∘.
Investigations on the momentum-dependence of the decay of image-potential electrons on Cu(100) will be presented underlining the capabilities of this instrument.