0428同步年報-2021-全

Facility Status 091 delivered user time to scheduled user time, mean time between failures (MTBF) is the ratio of scheduled user time to number of faults, and beam stability index is the shot- to-shot photon intensity variation of the diagnostic beamline with a ratio less than 0.1%. In summary, by 2021, availability was 97.4% with a scheduled user time of 5,040 hours, MTBF was 115 hours, and time of beam stability was 97.5%. Downtime and Failure Analysis of the TLS In 2021, a total of 43 beam trips were recorded. The accumulated downtime of each subsystem is presented in Fig. 3 , and the total accumulated downtime was 129 hours. Among the various contributors to downtime (including earthquakes, power spikes, noises, and beamlines), the RF system accounted for the largest proportion at 47.3 hours. Taiwan Photon Source (TPS) Machine Parameters of the TPS As a synchrotron light source that has only been made available to users for less than 6 years, the TPS accelerator features low emittance, top-up injection, superconductivity RF module operation, and high stability. Table 3 lists the major parameters of the TPS storage ring for current operations. The TPS accelerator tunnel comprises a storage ring and a booster ring that are arranged concentrically. Statistics of TPS Machine Operation The TPS was first made available to users in the fourth quarter of 2016 with a beam current of 300 mA, which was increased to 400 mA in December 2017 and subsequently reached 450 mA in the Table 3 : Main parameters of TPS storage ring. Fig. 2 : Beam stability index (0.1%), availability, and MTBF of the TLS from 2011 to 2021. Fig. 3 : Downtime contribution of the TLS accelerator in 2021. (Downtime 129 hours) Beam energy (GeV) 3 Circumference (m) 518.4 Current/design (mA) 400/500 Number of buckets 864 Beam emittance (ε x /ε y ) (nm-rad) 1.6/0.016 Momentum compaction (α 1 /α 2 ) 0.0024/0.0021 RF voltage (MV) 2.8 Synchrotron tune (ν s ) 5.42 x 10 -3 later period of 2020. In 2021, the beam current reached 500 mA for users. The scheduled user time, delivered user time, and availability of TPS from 2019 onward are presented on a quarter-by-quarter basis in Fig. 4 (see next page). In 2021, annual availability was 97.9%, scheduled user time was 4,681 hours, and MTBF was 106 hours ( Fig. 5 , see next page).