Frankfurt 2006 – scientific programme

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A: Atomphysik

A 19: Wechselwirkung mit VUV and X-FEL Licht

A 19.4: Talk

Thursday, March 16, 2006, 15:15–15:30, H7

Photoionisation of rare gas atoms by VUV-FEL radiation — •Michael Wellhöfer¹, Jon Tobias Hoeft¹, Michael Martins¹, Wilfried Wurth¹, Markus Braune², and Jens Viefhaus² — ¹Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg, Germany — ²Fritz-Haber-Insitut, Faradayweg 4-6, 14195 Berlin, Germany

The Vacuum Ultra Violet - Free Electron Laser (VUV-FEL) at Hasylab/DESY has been set in operation in the beginning of 2005. This unique novel source yields very short laser pulses, typically 50fs and less, with very high photon flux up to 10¹³ photons per pulse. Due to the Self Amplified Spontaneous Emission (SASE) process of the VUV-FEL each pulse differs from the previous in intensity and wavelength. This demands a complete new data acquisition system to correlate the measurements with the individual pulse properties. Furthermore the VUV-FEL does not only generate laser pulses with one distinct wavelength, but also higher harmonics. Thus, to perform experiments with a well defined photon energy, e.g. for high resolution spectroscopy, a monochromator beamline has been designed and set in operation for user experiments mid 2005. The high intensity of the VUV-FEL allows not only experiments on diluted targets such as single atoms or free clusters within a single shot, but also experiments probing the non linearity of photon absorption. Thus, the full spectral information of a single shot is required. This can be accomplished by using zero order and first order beam simultaneously. In my talk I will present first results of photoionisation experiments on rare gas atoms.