Beam lifetime estimation for taiwan 3gev synchrotron light source

The demanding design features of Taiwan Photon Source (TPS), low emittance and small gap undulator vacuum vessels, cause Touschek scattering and gas scattering to play a major limitation role for beam lifetime. We calculate the Touschek lifetime based on the tracking procedure determining energy acceptance. The nonlinear synchrotron oscillation due to large second- order momentum compaction factor is included in the energy acceptance calculations. Small vertical ID gaps are imposed in the tracking procedure. Besides, the gas scattering lifetime is estimated with varying gas pressure. The possible improvement solutions for lifetime will be addressed.