Keyword: closed-orbit
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MOPP027 First Beam-based Test of Fast Closed Orbit Feedback System at GSI SIS18 controls, synchrotron, acceleration, feedback 153
 
  • R. Singh, A. Doring, P. Forck, K. Lang, S.H. Mirza, D. Rodomonti, D. Schupp, M. Schwickert, H. Welker
    GSI, Darmstadt, Germany
  • A. Bardorfer
    I-Tech, Solkan, Slovenia
 
  Funding: European Unions Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871 (ARIES). German Academic Exchange Service under Personal Reference No. 91605207.
The SIS18 synchrotron of GSI will be used as a booster ring for the SIS100 synchrotron built in the scope of the FAIR project. In order to preserve the beam quality during the whole acceleration ramp, a new closed orbit feedback (COFB) system is implemented at the SIS18 which operates with the existing BPMs and steerer magnets. The system aims for a bandwidth of several 100 Hz and robustness against the variation of the response matrix and the beam rigidity during the ramp. The architecture of the system and the results of the first beam-based test of the COFB hardware are presented. As a first step, the orbit correction is performed over the entire ramp using the response matrix corresponding to injection energy only taking the beam rigidity into account. Experimental observations of the bandwidth limitations arising from the temporal delay of the steerer power supplies and the spatial model variation during the ramp are compared with simulations. It is found that the temporal and the spatial model mismatch have similar effect on the achievable bandwidth of the COFB.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP027  
About • paper received ※ 07 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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WEBO03 Development of MTCA.4-Based BPM Electronics for SPring-8 Upgrade electron, electronics, FPGA, LLRF 469
 
  • H. Maesaka, T. Fukui
    RIKEN SPring-8 Center, Innovative Light Sources Division, Hyogo, Japan
  • H. Dewa, T. Fujita, M. Masaki, C. Saji, S. Takano
    JASRI/SPring-8, Hyogo-ken, Japan
 
  We have developed a new button-BPM readout electronics based on the MTCA.4 standard for the low-emittance upgrade of SPring-8 [*]. Requirements for the BPM system are a high single-pass BPM resolution of better than 100 µm for a 100 pC injected bunch to achieve first-turn steering in the commissioning of the upgraded ring and a highly stable COD BPM within 5 µm error for 1 month to maintain the optical axis of brilliant x-rays for users [**]. We designed an rf front-end rear transition module (RTM) having band-pass filters, low-noise amplifiers, step attenuators, and calibration tone generators. The rf signal is detected by a 16-bit 370 MSPS high-speed digitizer advanced mezzanine card (AMC) developed for the new low-level rf system of SPring-8 [***]. The firmware of the FPGA on the digitizer AMC was newly developed to implement various functions of the BPM system. We evaluated the readout system at a laboratory and then tested at the present SPring-8 storage ring with a prototype BPM head for the SPring-8 upgrade. We confirmed that the new readout system satisfies the requirements for the single-pass BPM resolution and the COD BPM stability.
* SPring-8-II Conceptual Design Report, http://rsc.riken.jp/pdf/SPring-8-II.pdf
** H. Maesaka et al., Proc. IBIC’18, paper TUOC04.
*** T. Ohshima et al., Proc. IPAC’17, paper THPAB117.
 
slides icon Slides WEBO03 [3.340 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEBO03  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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WEPP030 Betatron Phase Advance Measurements Using the Gated Turn-by-turn Monitors at SuperKEKB betatron, coupling, luminosity, detector 585
 
  • G. Mitsuka, K. Mori, M. Tobiyama
    KEK, Ibaraki, Japan
 
  In the SuperKEKB commissioning Phases 2 (Feb.-Jul., 2018) and 3 (from Mar. 2019), the betatron phase advances between adjacent beam position monitors have been measured using a total of 138 gated turn-by-turn monitors. A fast RF gating of the monitors enables turn-by-turn beam position detections by focusing only on an artificially-excited non-colliding bunch, while leaving colliding bunches unaffected. Betatron phase advances measured by the gated turn-by-turn monitors and accordingly obtained betatron functions were consistent with the closed orbit measurements. High signal-to-noise ratio were achieved by advanced signal extraction methods such as NAFF, SVD, and independent component analysis.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP030  
About • paper received ※ 03 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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