BEHAVIOR OF VACUUM PRESSURE IN TPS VACUUM SYSTEM

Taiwan Photon source (TPS) is in its first stage commissioning in 2014-2015. The vacuum systems of TPS were installed for commissioning since August 2014. After four months performance testing and subsystem integration, the commissioning of booster ring began on 12 December and then the first 3 GeV beam was stored on 31 December. 100mA beam current, 35Ah accumulated beam dose was archived in March 2015 before machine shut down. The average pressure in storage ring is 2.8×10 Pa before commissioning, rising to 1.33×10 Pa with 100mA beam current. In 35Ah accumulated beam dose, the target of beam cleaning effect has reached to 8.92×10 Pa/mA. The vacuum performance, experience and events during commissioning will be presented in this paper.