EXPERIENCE WITH THE PHOTOINJECTOR LASER AT FLASH

The photoinjector laser system of FLASH is a key el-ement for the generation of high quality electron beams required for a stable and reliable operation of the facility. FLASH is the VUV and soft X-ray FEL user facility at DESY. FLASH is based on superconducting accelerating structures allowing to accelerate electron bunch trains of a length of up to 800µs with a repetition rate of 10 Hz. Based on the standard 1 MHz pattern, the laser provides to some extend a flexible bunch train structure. We report on oper-ational issues and on the performance of the laser system and its integration into the machine protection system