Soft X-ray grating compressors for free-electron-laser pulses

We discuss the design of double plane grating compressors to be used for chirped pulse amplification on free-electron laser (FEL) ultrashort pulses at energies higher than 100 eV. In particular, the design of a grating compressor for wavelength emission centered at 10 nm is demonstrated. The XUV efficiency measurements in the 8-12 nm range of the gratings to be used in a double plane grating compressor realized for an upcoming experiment planned at FERMI is presented and discussed. The overall instrument efficiency is furthermore analyzed.