Damage study for the design of the European XFEL beamline optics

The European X-Ray Free Electron Laser will deliver high intensity ultrashort pulses of x-rays. The results of the x-ray interaction with matter in such a regime are not yet fully understood and the energy threshold for surface modifications remains unknown. The behavior of optical components under irradiation is a major issue for the European XFEL project. In fact some experiments rely on the coherence and high quality wave front of the beam and any degradation, even on the nanometer scale, of the x-ray optical components will affect the performance of these experiments. Hence investigation of radiation effects on materials is needed. We will describe the on-going program at the European XFEL which aims at developing new approaches for beamline design specific to FEL light source. Different tools are used in order to simulate the beam propagation and interaction with optical elements.