Feasibility Study of X-ray Free Electron Lasers in Fourth Generation Storage Rings

Sammanfattning: This thesis studies the feasibility of a cavity based X-ray free electron laser in a fourth generation storage ring. The cavity design allows for modulation of the electron beam over several passes through the undulator. Simulations based on the PETRA IV facility are done to create the photon flux spectrum of a light pulse produced by an undulator. This spectrum is subsequently modeled to pass through an optical cavity with four diamond mirrors, and the efficiency of the cavity evaluated. A direct comparison to the shotnoise of the beam is made, to determine whether the light after one pass through the cavity will be intense enough to start the amplification needed for coherent emission. The effects of the energy spread and peak current are analysed: decreasing the energy spread and increasing the peak current have both the same effect of increasing the energy of the light produced in a single pass. The central result of the study is that the cavity based X-ray free electron laser seems feasible.