Author: Lin, Q.
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TUPB12 Machine Studies with Libera Instruments at the SLAC Spear3 Accelerators 284
 
  • S. Condamoor, W.J. Corbett, D.J. Martin, S. C. Wallters
    SLAC, Menlo Park, California, USA
  • M. Cargnelutti, P. Leban
    I-Tech, Solkan, Slovenia
  • L.W. Lai
    SSRF, Shanghai, People's Republic of China
  • Q. Lin
    Donghua University, Shanghai, People's Republic of China
 
  Turn-by-turn BPM readout electronics were tested on the SPEAR3 booster synchrotron and storage ring to identify possible improvements for the booster injection process and to characterize processor performance in the storage ring. For this purpose, Libera Spark and Libera Brilliance+ instruments were customized for the booster (358.4 MHz) and storage ring (476.3 MHz) radio-frequencies, respectively, and tested during machine studies. Even at low single-bunch booster beam current, the dynamic range of the Libera Spark readout electronics provided excellent transverse position measurement capability during the linac-to-booster injection process, the energy ramp-up phase and during beam extraction. Booster injection efficiency was also analyzed as a function of linac S-band bunch train arrival time. In the SPEAR3 storage ring turn-by-turn Libera Brilliance+ measurement capability was evaluated for single and multi-bunch fill patterns as a function of beam current. The single-turn measurement resolution was found to be better than 10 microns for a single 3 mA bunch. The horizontal single-bunch damping time was then determined with the 238 MHz bunch-by-bunch feedback system on and off.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB12  
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WEPB06 Time-Synchronous Measurements of Transient Beam Dynamics at Spear3* 441
 
  • Q. Lin, Z.H. Sun
    Donghua University, Shanghai, People's Republic of China
  • W.J. Corbett, D.J. Martin, K. Tian
    SLAC, Menlo Park, California, USA
 
  Funding: Work supported by the China Scholarship Council and the US Department of Energy Contract DE-AC03-76SF00515, Office of Basic Energy Sciences.
Multi-bunch beam instabilities can often be controlled with high-speed digital bunch-by-bunch feedback systems. The detected motion is based on charge centroid measurements that, for short bunches, cannot resolve intrabunch charge dynamics. To compliment the BxB data, we installed a fast-gated camera with a rotating mirror to sweep visible-light synchrotron radiation across the camera CCD. The SR measurements present a complimentary view of the motion. For this work we generated transient beam events in SPEAR3 using the BxB feedback system and synchronously observed the motion on the camera. Results are presented for a high-order multibunch beam instability and for single bunch drive-damp experiments.

 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB06  
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