FRAA02
SLAC, Menlo Park, California, USA
BNL, Upton, Long Island, New York, USA
SLAC National Accelerator Laboratory is developing LCLS-II, a superconducting linear accelerator based free electron laser capable of a repetition rate up to 1 MHz. To deliver the FEL beam with minimal power loss and wavefront distortion, we need grazing-incidence plane mirrors with height errors below 1nm rms, under operational conditions. We also need to mitigate thermal effects of a complex photon energy-dependent thermal profile. We discuss a mirror cradle that minimizes figure error using variable length water cooling through a gallium-indium eutectic bath, and curve correction with an off-axis bender. We present thermal and mechanical analysis, design and prototyping results of figure sensitivity under bender corrections.
