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MO: Fachverband Molekülphysik

MO 30: Poster: Spectroscopy in He droplets

MO 30.1: Poster

Dienstag, 20. März 2007, 16:30–18:30, Poster A

Characterisation of the Even-Lavie nozzle as a source for a pulsed helium nanodroplet beam — •Christoph Strauss, Oliver Bünermann, Marcel Mudrich, and Frank Stienkemeier — Universität Freiburg, Physikalisches Institut, D-79104 Freiburg, Germany

We present first measurements with the Even-Lavie valve to characterise the flux and the peak intensity of a pulsed He droplet beam. Both mass-spectrometric measurements of the undoped beam as well as surface ionization detection of alkali-doped helium droplets were performed. The nozzle is designed for high repetition rates up to 1000Hz at temperatures down to 10K. Due to the short opening time (20μs) high peak intensities can be generated at moderate pumping speeds in the source chamber. Because of a low electric power consumption ( < 3W ) and an efficient cooling of the copper housing of the Even-Lavie valve, the low cooling power of a standard closed cycle refrigerator establishes cryogenic conditions. Eventually, the pulsed source will be used in combination with kHz laser ablation and kHz femtosecond lasers.