Cited by 125
Shanghai University of Engineering Science
Publishes on Nanoparticles: synthesis and applications, Catalytic Processes in Materials Science, Magnesium Alloys: Properties and Applications. 4 papers and 179 citations.
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Beam Position Measurement (BPM) system is an indispensable diagnosis instrument that is used to monitor the beam position information. A digital BPM (DBPM) has been designed for Shanghai Synchrotron Radiation Facility (SSRF). Among the different types of data that the DBPM provides, the Close Orbit (CO) data is an important one which is applied to beam monitoring, as well as feedback to keep the beam orbit stable. Therefore, great efforts are required to optimize its performance. We implemented an off-tuned sampling method by using a Digital Phase-Locked Loop (DPLL) based on Alexander phase detector, and an interleaved switching scheme to address variance in the long-term performance of the sampling channels. To evaluate these sampling methods, we conducted commissioning tests in the SSRF. Test results indicate that the position resolution of the CO data can effectively be enhanced from 3.62 μm to 0.16 μm by the interleaved switching scheme while no obvious performance difference was observed with or without the off-tuned sampling method applied which was probably due to good performance of the sampling channels in the DBPM electronics.
BPM (Beam Position Measurement) system is one of the most important beam diagnostic instruments in accelerators. A fully digital BPM (DBPM) has been designed for SSRF (Shanghai Synchrotron Radiation Facility). As Analog-to-Digital Converter (ADC) is one crucial part in the DBPM system, the sampling methods should be studied to achieve optimum performance. We implemented different sampling modes and compared them through tests. Meanwhile, long term variation among four sampling channels is another concern, which would introduce errors in beam position measurement. We designed an interleaved distribution scheme to address this issue. To evaluate these sampling methods, we conducted commissioning tests with the beam in SSRF. Test results indicate that with proper sampling methods, a turn-by-turn (TBT) position resolution better than 1 um is achieved, and the slow-acquisition (SA) position resolution is enhanced from 4.28 μm to 0.17 μm successfully with interleaved distribution applied, both beyond requirement.