Abstract:
FLASH II is a major extension of the existing FLASH facility at DESY. It has been proposed in collaboration with the Helmholtz-Zentrum Berlin (HZB). FLASH II is a seeded FEL in the parameter range of FLASH. The final layout of the undulator section of FLASH II allows for different seeding schemes. So that seeding with an HHG source as well as seeding in cascaded HGHG scheme and several combination of these schemes are possible. However, for the shortest wavelengths down to 4 nm the cascaded HGHG scheme is considered. It consists of two frequency up conversion stages utilizing a Ti:Sa laser based seeding source in deep UV range. We present and discuss start-to-end simulation studies for the shortest wavelength generated in the HGHG cascade of FLASH II.