Mainz 2017 – scientific programme

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A: Fachverband Atomphysik

A 26: Poster Session II

A 26.24: Poster

Wednesday, March 8, 2017, 17:00–19:00, P OG1

VMI spectrometer for studying interaction of atoms and molecules with Terahertz radiation — •Patrick Froß, Yonghao Mi, Nicolas Camus, Lutz Fechner, Thomas Pfeifer, and Robert Moshammer — Max-Planck-Institut für Kernphysik, Heidelberg, Germany

Thanks to the advancements in strong laser technologies, generation and detection of strong Terahertz (THz) radiation has become possible in the recent years. Because of their low frequencies, they appear as ideal to study ultrafast phenomena in atoms and molecules without disturbing/interacting with the interrogated systems. In order to investigate the effect of THz and their imprint on particles arising from ionization with visible light, we build a dedicated spectrometer. First, this spectrometer has focusing optics which overcome the difficulties due to a low THz power inherent from the low power conversion efficiency of current pulsed THz generation. Second, the spectrometer frame is such that the voltage settings can be changed between Reaction Microscope (ReMi) settings allowing coincident measurement of all charged particles and VMI settings in which the multi-hit limitation of usual ReMis is overcome allowing to record statistics faster. An MCP-phosphor-screen-detector records a collective image of the charged particles that can mathematically be transformed to get the original 3D-momentum-distributions. The particle trajectories were simulated to find a potential configuration with optimal VMI-properties for the ReMi-spectrometer frame. First experimental results were obtained from photoionization of Argon with 25fs-IR-laser-pulses.