Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 47: Electronic Structure of Surfaces: Spectroscopy, Surface States

O 47.5: Poster

Dienstag, 8. März 2016, 18:15–20:30, Poster E

Towards ToF Momentum Microscopy With CW Sources Using an Ultrafast Chopper Scheme — •Anna Zaporozhchenko^1,2, Olena Fedchenko¹, Katerina Medjanik^3,1, Sergej Chernov¹, Andreas Oelsner⁴, Hans-Joachim Elmers^1,2, and Gerd Schönhense^1,2 — ¹Institut für Physik, JOGU, 55099 Mainz, Germany — ²Graduate School of Excellence MAINZ, 55128 Mainz, Germany — ³Lund University, MAX IV Laboratory, 22100 Lund, Sweden — ⁴Surface Concept GmbH, 55124 Mainz, Germany

The use of time-of-flight techniques for high-resolution spectroscopy and momentum microscopy requires a defined time structure of the photon beam. The time resolution of 3D (x,y,t)-resolving detectors, e.g. the delay-line detector, is typically 150 ps [1]. Thus a period of the exciting photon pulses of 200 ns (pulse rate of 5 MHz) yields more than 1000 time slices, sufficient for high-resolution spectroscopy. We developed an ultrafast electron-optical deflector system capable of chopping the desired pulse repetition rate out of a faster pulse train or even out of a continuous-wave signal. A first experiment with a laboratory He source was performed. In the first prototype pulse profiles of 2 ns width have been achieved. One goal is to chop lower pulse rates from the 100 or 500 MHz multibunch signal of storage rings. The current status of this development will be shown. Funded by BMBF (05K13UM1)