THE LCLS SINGLE-SHOT RELATIVE BUNCH LENGTH MONITOR SYSTEM

摘要

The Particle Beam Physics Lab (PBPL) at UCLA is developing a single-shot relative bunch length monitor system for the Linac Coherent Light Source (LCLS) X-ray Free Electron Laser at SLAC. To ensure high-quality lasing, feedback systems are needed. The bunch length monitor system will be a crucial part of the linac longitudinal feedback system, which is necessary to keep the final peak beam current stable. The system will consist of two single-channel detector arrangements, one after each bunch compressor, and will use the coherent synchrotron radiation (CSR) and coherent edge radiation (CER) from bunch compressor chicane dipole magnets to monitor the bunch length. Details of the system are presented, with an emphasis on the device for bunch compressor one (BC1), and the system is compared to alternatives. Plans for testing are presented as well.