Talk will cover state-of-the-art photocathodes for bright-beam and spin-polarized-beam generation.

The implementation of High Pressure Rinse (HPR) not only ensures thorough cleaning of the inner high purity niobium surface of Superconducting Radio Frequency (SRF) cavities but also unlocks their full potential for achieving peak performance. By effectively removing contaminants and impurities, HPR sets the stage for enhanced superconducting properties, improved energy efficiency, and superior operational stability. A simulation tool has been developed, facilitating the accurate prediction of both the quality and effectiveness of the rinsing process before its execution in the cleanroom. This tool, the focus of this paper, stands as a pivotal advancement in optimizing Superconducting Radio Frequency (SRF) cavity preparation. Furthermore, our paper will also present correlations with cavity cold testing results, demonstrating the practical applicability and reliability of the simulation predictions in real-world scenarios.

In this paper, the design of a compact C-band SLED RF Pulse Compressor for a Very High Electron Energy (VHEE) FLASH machine is presented. A spherical cavity RF pulse compressor - selected because of its compactness and relative ease of fabrication - is adopted to compress the 5 𝜇s RF pulse, down to 1 𝜇s obtaining a peak power gain greater than 5. Both the RF and thermo-mechanical design have been carried out, including a sensitivity study to evaluate the mechanical tolerances, possible tuning methods, and the cooling system. The main parameters of the full RF design (spherical storage cavity + mode converter/polarizer) and the final mechanical design of the structure are presented.