MAX-lab, Lund
HZB, Berlin
Lund University, Division of Atomic Physics, Lund
The first generation of coherent harmonic radiation from the MAX-lab test FEL have recently been achieved. The 380 MeV electron beam has been seeded by a 263 nm Ti:Sapphire laser and coherent radiation in the harmonics 1 to 4 (263 66 nm) has been produced both in linear and circular polarization mode. The facility consists of a photo cathode RF gun, the MAX injector (two 95 MeV linacs placed in a recirculator), beam transport including compression optics and the two undulators (modulator and radiator) separated by a four magnet chicane for bunching control. The radiator undulator is of Apple type providing tunable polarization. The basic characterization of the source with dynamic studies of laser energy, undulator gap and chicane influence on the coherent harmonic signal will be reported.
MAX-lab, Lund
Lund University, Division of Atomic Physics, Lund
Electro-optical spectral decoding was used to on-line monitor the arrival time of the electron bunches relative to the seed laser pulse at the test FEL facility at MAX-lab. An infrared chirped pulse coming from the seed laser is influenced by an electron bunch induced birefringence in a ZnTe birefringent crystal and the arrival time is determined from its spectrum. The possibility of running simultaneously with the FEL allowed for a feedback scheme to be built to compensate for the long term drifts in the system. Also, the whole system (the accelerator and the lasers) were synchronized to the power grid frequency. This lock increased the stability and was monitored by the EO setup. Measurements of the bunch length were performed and their correlation with arrival time pointed towards main contributors to the jitter in the system.