| We report on first differential experiments of few-photon multiple ionization of He, Ne and small molecules by intense FEL radiation at FLASH using a Reaction Microscope. Measurements were performed at wavelengths of 44 nm (28.2 eV), 32 nm (38.7 eV) and 28 nm (44.9 eV) and estimated intensities in the range of 10¹2; – 10¹4; W/cm². Experimental results will be presented and discussed in terms of possible multiple ionization pathways due to the instantaneous or sequential absorption of several photons. |
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