Simultaneous Operation of Three Laser Systems at the FLASH Photoinjector

The free-electron laser facility FLASH at DESY (Hamburg,Germany) operates two undulator beamlines simultaneously. Both undulator beamlines are driven by a common linear superconducting accelerator with a beam energy of up to 1.25 GeV. The superconducting technology allows the acceleration of trains of several hundred micro second spaced bunches with a repetition rate of 10 Hz. A fastkickers-septum system is installed to distribute one part ofthe electron bunch train to FLASH1 and the other part to FLASH2 keeping the full 10 Hz repetition rate for both beamlines. In order to deliver different beam properties to each beamline, the FLASH photoinjector uses two independent laser systems to generate different bunch pattern and bunch charges. One laser serves the FLASH1 beamline, the other the FLASH2 beamline. A third laser with adjustable laser pulse duration is used to generate ultra-short bunches for single spike lasing