Investigation and elimination of orbit distortion sources to achieve a high-quality photon beam at the Taiwan Photon Source

High beam stability is important to obtain a brilliant photon beam. There are many sources which can negatively affect beam stability, such as mechanical vibrations, electrical noise and malfunction of power supplies, etc. These sources are hard to avoid completely by careful design and may appear any time after installation work. To identify possible sources and study their effect to beam motion, a systematic study was performed starting with specific hardware installations. A method was developed to quickly identify locations of multiple perturbations and to observe vibrations and low-level undesired alternating magnetic fields. As for mechanical vibrations, a severe beam motion during beam commissioning was caused by quadrupole and vacuum chamber vibrations. The transfer of such vibrations to the beam were simulated by forced-shaking. Inversion of the response matrix together with singular value decomposition could identify perturbations by electrical noise originating from a nearby radio frequency system and cooling fans. After eliminating these detrimental factors, a high-quality beam, stable to less than 10% of the beam size, was achieved at the Taiwan Photon Source.