Cross-correlator for the diagnostics of 3D ellipsoidal shaped UV laser pulses for the future XFEL low-emittance photo-injector

Summary form only given. The European X-ray Free Electron Laser (XFEL) is being built at DESY in Hamburg. Its ultrashort X-ray flashes with extremely high peak and average brilliance are expected to allow unprecedented experiments with atomic resolution on femtosecond time scales. The Photo Injector test facility at DESY, Location Zeuthen (PITZ) is responsible for the developing of the electron source for the XFEL. The laser driven RF gun has to fulfill very challenging specifications on electron source performance for linac based FELs, namely it should provide electron bunches with high bunch charge (~1 nC) and extremely low transverse emittance (<; 1 mm mrad). The RF photo-injector drive laser pulse shaping is a key issue to achieve such a performance. It was theoretically shown [1] that the 3D ellipsoidal shape of the UV pulses driving the photo-injector is the optimal.