Liu, Y.-C. Cheng, C.M. Chung, T.Y. Hsiao, Y.M. Tseng, F.H. JACoW Publishing Geneva, Switzerland 2673-7035 978-3-95450-224-0 10.18429/JACoW-FLS2023-WE4P20 English 192-195 photon electron alignment synchrotron feedback Contribution to a conference proceedings 2024 2024-01 https://doi.org/10.18429/JACoW-FLS2023-WE4P20 http://jacow.org/fls2023/papers/we4p20.pdf Taiwan Photon Source (TPS) has been open to user operation since 2016. We report the alignment results of tandem EPUs in one double mini-beta y long straight section. The goal is to increase the brilliance of the synchrotron lights produced by the tandem EPUs through well-alignment and using a phase shifter to achieve both spatial and temporal coherence. The calculated brilliance gain of the tandem EPUs is compared, and the difference between the measured and numerical results is analyzed.