Design study of a new SLED system with a biplanar 3-dB power divider and dual side-wall coupling-irises for the PAL XFEL

摘要

The Stanford Linear Accelerator Energy Doubler (SLED) system for the PAL (Pohang Accelerator Laboratory) XFEL (X-ray Free Electron Laser) is required to operate with an RF input power of 80 MW and a pulse width of 4 μs. Due to the high radiation dose from RF breakdown at coupling holes and power dividers in such a high-power operation, a modification of the original SLED system is called for. We designed a new SLED system with a biplanar 3-dB power divider and dual side-wall coupling-irises by using a finite-difference time-domain (FDTD) simulation. The new SLED system proved to be a good solution that reduced the probability of RF breakdown in high-powered operations due to the reduced field gradient and surface current. In addition, a time-domain simulation was carried out to estimate the performance of new SLED system and to study the process for the question of the SLED output waveform.