Correlation between copper photoemission spectra and spectra of x-ray pulses produced by sub-picosecond laser-irradiated noble gas clusters

Interaction of a cluster jet with a very intense laser pulse generates x-rays in the keV domain. Many features of this type of source are well characterized and understood but their temporal structure is still being discussed. We performed experiments on photoelectron emission of a pure copper metallic sample irradiated by such a source of x-rays. We determined the best laser and gas jet parameters in order to enhance the photoemission yield. The maximum signal was obtained with 30 bars of xenon irradiated by 250 fs 75 mJ pulse at 800 nm, corresponding to an intensity of 2.10 16 W/cm 2 . We were able to observe a peak of Auger electrons at 62 eV in the photoelectron spectrum. This suggests that pulse duration measurements based on the Laser Assisted Auger Decay (LAAD) technique are possible.