2020同步年報

Facility Status 089 Mean Time Between Failure (MTBF) as the ratio of scheduled user time to number of faults, and beam-sta- bility index as the photon-intensity variation shot to shot of the diag- nostic beamline with a ratio better than 0.1%. In summary of 2020, the availability was 93.3% with a sched- uled user time 5,112 hours; MTBF was 232.4 hours, and beam stability was 95.5% with 0.1% tolerance. In November, the klystron of the LINAC failed; the only spare klystron was sent back to its manufacturer THALES in France for high-power test due to an impact loading during air delivery. It took ten days to try to recover the failed klystron; the availability thus decreased from 97.6% to 93.3%. In December it took another three days to replace it with the delivered new klystron. Downtime and Failure Analysis of TLS In 2020, in total there were 22 beam trips. The accumulated downtime of each subsystem is shown in Fig. 3 , with 344.3 hours in total. The major downtime, 303.7 hours, was contrib- uted from the LINAC system, in which the klystron event took 301 hours. The others including earthquake, power spike, noise, beamline, injection kicker, RF system etc . became minor in 2020. Table 3 : Main parameters of TPS storage ring. Beam energy (GeV) 3 Circumference (m) 518.4 Current/design (mA) 450/500 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 95.5% 97.6% 55.4 44.8 139.9 182.1 83.2 98.7 245.7 319.4 192.1 213.7 0 50 100 150 200 250 300 350 400 60% 65% 70% 75% 80% 85% 90% 95% 100% MTBF (Hour) Stability & Availibility ΔI/I 0 (<0.1%) Availability MTBF 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 PS,1.91, 0.6% Cryogenic, 1.3, 0.4% BD, 0, 0.0% RF, 5.70 , 1.7% I&C, 10.36, 3.0% Operation, 3.21, 0.9% Magnet, 0, 0.0% Vacuum, 0, 0.0% Utility, 0, 0.0% Safety, 0, 0.0% Linac, 303.66, 88.2% Other, 18.15, 5.3% Downtime of 344.3 hours in 2020 Fig. 3 : Downtime contribution of TLS accelerator in 2020. (Downtime 344.3 hours) Fig. 2 : Summary of beam-stability index 0.1%, availability and MTBF of TLS from 2011 to 2020. Taiwan Photon Source (TPS) Machine Parameters of TPS As a synchrotron light source opened to users less than five years ago, TPS accelerator features low emittance, top-up injection, superconductive RF-module operation and high stability. Listed in Table 3 are the major parame- ters of the TPS storage ring for current operation. The TPS accelerator tunnel includes a storage ring and a booster ring concentrically. Statistics of TPS Machine Operation TPS was first opened to users in the last quarter of 2016 with beam current 300 mA, raised to 400 mA in December 2017, and then regularly reached 450 mA in the latter days of 2020. Both scheduled and delivered user time and the availability since 2018 are shown in Fig. 4 , quarter by quarter. In 2020, the annual availability was 98.5% with scheduled user time 4,647 hours; MTBF attained 160.2 hours as shown in Fig. 5 together with the year statistics since 2017.