Design of a wavefront sensor for nanofocusing characterization at SHINE

SHINE is a high repetition rate X-ray free electron laser (XFEL) facility under construction in Shanghai, China. The coherent imaging of single molecule and single particle endstation (CDS) is one of the instruments initially built, and this instrument requires a 100-nanometer focus. To achieve such a focusing, a K-B system with 7 mrad grazing angle and Ir coating is preferred to enlarge the numerical aperture. Notably, a wavefront sensor based on the Talbot interferometer has been designed to characterize the nanofocusing. The heatload on the grating and YAG:Ce screen will be a big problem for high repetition rate. We proposed a shutter to migrate heat to ensure the grating and YAG:Ce screen working properly under a high average transport power.