ABSTRACT
Our objective in recent years has been to achieve improved single-shot PES data based on a pulsed Ni-like Pd ion, Ad - 4p 85 eV x-ray laser used in conjunction with electron time-of-flight (eTOF) spectroscopy. The soft x-ray laser has a high photon flux (>1012/pulse), 4 - 5 ps pulse duration and narrow line width (AE/E-2 x 10"5). This photon energy has a large photo-ionisation cross-section for valence band and shallow core level
was used on this shot. It is noted that the x-ray laser beam overfilled the optical beam on the sample so that there are detected photoelectron signals from heated and unheated regions of the foil. It is observed that the 3d peak intensity has been lowered and there exists a small foot just before the strong onset at -50 ns. The latter feature is associated with bound electrons above the Fermi level which are being excited by the pump beam. Increasing the pump energy by a further factor of ten generates a strong electron signal before 50 ns that indicates the sample is in an ionized state. These experiments can be repeated by changing the pumping parameters. For example, by controlling the pump energy different states of matter can be studied. Further experiments are ongoing to study the relaxation processes at different time delays between the probe and the pump.
