High-repetition-rate photoelectron spectroscopic diagnostics for SHINE XFEL using time-of-flight spectrometers

Due to their ultrashort pulse duration and high peak brightness, x-ray free-electron lasers (XFELs) have emerged as one of the most powerful tools at the forefront of scientific research. Non-invasive spectral diagnostics of XFEL pulses is an emerging necessity to enhance their operational capability. This paper introduces a time-of-flight photoelectron spectrometer designed for high-repetition-rate XFELs. The instrument is primarily employed to provide high-resolution spectral measurements within the 400-3000 eV range. The energy resolution of the spectrometer itself can reach 0.06 eV. Detailed descriptions of its design principles, structural components, and data acquisition systems are provided, and simulations are conducted to assess the influence of factors such as spot size on energy resolution, ensuring the instrument's reliability and stability in practical applications. Taking the above influencing factors into account, the energy resolution of the photoelectron spectrometer in the final energy spectrum measurement can theoretically reach 0.5 eV. This research will offer significant technical support for the optimization of free-electron lasers and the execution of ultrafast scientific experiments.