• E. Prat, W. Decking, T. Limberg
  DESY, Hamburg

This paper studies the impact of transverse dispersion on the SASE radiation power sensitivity with respect to the electron beam energy off-set. Both measurements and simulations are presented. By correcting the spurious dispersion inside the undulator region, the electron beam energy bandwidth is increased considerably, which decreases the SASE power jitter due to electron energy fluctuations.

• E. Prat, C. Gerth, K.E. Hacker
  DESY, Hamburg

At the Free Electron Laser in Hamburg (FLASH), when the electron beam is accelerated some degrees off-crest in the first accelerator module as during SASE operation, a correlation between the longitudinal position and the beam energy is induced. Between the second and the third dipole of the first bunch compressor (BC2), the horizontal beam position correlates linearly with the beam energy. With additional vertical dispersion, the beam is tilted in the x-y plane in this region, thereby increasing the projected vertical emittance. A systematic study of how vertical dispersion tilts the beam at the BC2 and causes an increase of the vertical emittance is presented here. The dispersion is generated by applying vertical trajectory bumps through the first accelerator module.