The Taiwan Light Source (TLS) is a third-generation light source with low operating energy, 1.5 GeV, which is used as ultra-violet and soft x-ray light source. A Superconducting RF cavity designed by Cornell University and tested at Cornell Electron Storage Ring (CESR) will be installed at TLS. The 500 mA beam current upgrade project at TLS is expected to reach the following basic goals: 1) reducing the longitudinal coupled bunch instability, 2) increasing the stored beam current by factor of two, 3) maintaining the beam lifetime by doubling the operating gap voltage. The RF cavity and beam parameters calculation will be discussed. Calculation for radiation shielding and cryogenic safety will be presented. The HFSS simulation results for the cavity modes, components of high-power waveguide transmission system and the coupling parameters will be addressed.

A beam combiner, which can combine multiple Gaussian beams into a single one, has many important applications, such as high-power radar and weapon. In this paper, we propose a new scheme of the design of high-power beam combiner at millimeter wavelengths by using wire grids. The design tool is to combine a genetic algorithm (GA) for global optimization and an Ansoft HFSS for rigorous electromagnetic computation. The design method is described in detail and the optimized results are presented. Finally, a brief summary is given.