GENERAL PHYSICS COLLOQUIUM _____ Title: Ultrafast processes at high x-ray intensity Speaker: Robin Santra, Centre for Free Electron Laser Science, DESY-Hamburg Time: Wednesday, 23 March, 2011 at 3:15 p.m. Place: Physics Auditorium, 3rd floor, Department of Physics Abstract After a brief introduction to x-ray-induced processes and x-ray free-electron lasers, the principles of x-ray multiphoton ionization will be discussed. Results from some of the first experiments carried out at the world's first x-ray free-electron laser, the Linac Coherent Light Source at SLAC National Accelerator Laboratory, will be presented and compared with theory. It will be shown that the x-rays from the LCLS are so intense that (a) an atom can be completely stripped of all its electrons; (b) inner-shell ionization can be as fast as the Auger decay of an inner-shell hole, thus leading to the efficient formation of double-core-hole states; and (c) the characteristics of the Auger decay process itself can be modified. _____ Coffee/tea and cake will be served at 3 p.m. David Field ******************************* Trine Binderup Department of Physics and Astronomy Aarhus University Ny Munkegade 120, building 1525 DK-8000 Aarhus C e-mail: trinebm@phys.au.dk Phone: +45 8942 3603 Office: 1525-324