Heidelberg 2015 – scientific programme
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MO: Fachverband Molekülphysik
MO 10: Experimental Techniques
MO 10.4: Talk
Tuesday, March 24, 2015, 15:15–15:30, PH/SR106
Characterization of an electron gun for diffraction experiments on controlled gas-phase molecules — •Nele L. M. Müller1, Sebastian Trippel1, Terence G. Mullins1, and Jochen Küpper1,2,3 — 1Center for Free-Electron Laser Science, DESY, Hamburg — 2The Hamburg Center for Ultrafast Imaging, Hamburg — 3Department of Physics, University of Hamburg
The aim of the presented work is to investigate the structure and dynamics of molecules in the gas-phase by electron diffraction experiments. Controlling the molecules’ state and spatial orientation increases the amount of information contained in electron diffraction patterns. The contribution presents our newly set-up electron gun that will be combined with an existing controlled-molecules apparatus. In the controlled-molecules setup gas-phase molecules are state-selected by means of electric deflection and then laser-aligned to serve as a well-defined sample [1]. The developed DC electron gun can produce up to 10 million electrons per pulse and uses an electro-static lens for focusing. The focusing electrodes are arranged in a configuration similar to a velocity map imaging spectrometer. Initially, they can be used to measure the spatial and velocity distribution of the electron pulse at the cathode. In combination with electron trajectory simulations this allows for further characterization of the electron beam, as for example the determination of pulse duration and coherence length. Electron diffraction data from solid state and gaseous samples will be presented.
[1]Trippel et al., Mol. Phys. 111, 1738-1743 (2013)