Keyword: feedback
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MOOB01 Beam Commissioning of SuperKEKB Rings at Phase-2 operation, detector, MMI, injection 6
 
  • M. Tobiyama, M. Arinaga, J.W. Flanagan, H. Fukuma, H. Ikeda, H. Ishii, S.H. Iwabuchi, G.M. Mitsuka, K. Mori, M. Tejima
    KEK, Ibaraki, Japan
  • G. Bonvicini
    Wayne State University, Detroit, Michigan, USA
  • E. Mulyani
    Sokendai, Ibaraki, Japan
  • G.S. Varner
    University of Hawaii, Honolulu,, USA
 
  The Phase 2 commissioning of SuperKEKB rings with Belle II detector began in Feb. 2018. Staring the commissioning of positron damping ring (DR), the injection and storage of the main rings (HER and LER) smoothly continued in Apr., 2018. The first collision has been achieved on 26th Apr. with the detuned optics (200 mm x 8 mm). Performance of beam instrumentation systems and the difficulties encountered during commissioning time will be shown.  
slides icon Slides MOOB01 [11.232 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOOB01  
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MOPA13 Fast Luminosity Monitoring for the SuperKEKB Collider (LumiBelle2 Project) luminosity, MMI, detector, monitoring 51
 
  • C.G. Pang, P. Bambade, S. Di Carlo, D. Jehanno, V. Kubytskyi, Y. Peinaud, C. Rimbault
    LAL, Orsay, France
  • Y. Funakoshi, S. Uehara
    KEK, Ibaraki, Japan
 
  LumiBelle2 is a fast luminosity monitoring system prepared for SuperKEKB. It uses sCVD diamond detectors placed in both the electron and positron rings to measure the Bhabha scattering process at vanishing scattering angle. Two types of online luminosity signals are provided, a Train-Integrated-Luminosity at 1 kHz as input to the dithering feedback system used to maintain optimum overlap between the colliding beams in horizontal plane, and Bunch-Integrated-Luminosities at about 1 Hz to check for variations along the bunch trains. Individual beam sizes and offsets can also be determined from collision scanning. This paper will describe the design of LumiBelle2 and report on its performance during the Phase-2 commissioning of SuperKEKB.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPA13  
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TUOC01 Integration of a Pilot-Tone Based BPM System Within the Global Orbit Feedback Environment of Elettra FPGA, controls, electron, Ethernet 190
 
  • G. Brajnik, S. Bassanese, G. Cautero, S. Cleva, R. De Monte
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  In this contribution, we describe the advantages of the pilot tone compensation technique that we implemented in a new BPM prototype for Elettra 2.0. Injecting a fixed reference tone upstream of cables allows for a continuous calibration of the system, compensating the different behaviour of every channel due to thermal drifts, variations of cable properties, mismatches and tolerances of components. The system ran successfully as a drop-in substitute for a Libera Electron not only during various machine shifts, but also during a user dedicated beamtime shift for more than 10 hours, behaving in a transparent way for all the control systems and users. The equivalent RMS noise (at 10 kHz data rate) for the pilot tone position was less than 200 nm on a 19 mm vacuum chamber radius, with a long-term stability better than 1 um in a 12-hour window. Two main steps led to this important result: firstly, the development of a novel RF front end that adds the pilot tone to the signals originated by the beam, secondly, the realisation of an FPGA-based double digital receiver that demodulates both beam and pilot amplitudes, calculating the compensated X and Y positions.  
slides icon Slides TUOC01 [6.468 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUOC01  
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TUPB12 Machine Studies with Libera Instruments at the SLAC Spear3 Accelerators booster, brilliance, injection, synchrotron 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.  
poster icon Poster TUPB12 [1.531 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB12  
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TUPC10 The Design of Scanning Control System for Proton Therapy Facility at CIAE controls, proton, cyclotron, interface 319
 
  • L.C. Cao, T. Ge, F.P. Guan, S.G. Hou, X.T. Lu, Y. Wang, L.P. Wen
    CIAE, Beijing, People's Republic of China
 
  A new proton therapy facility is being construted at CIAE. As a part of whole control system, the scanning control system is designed to scan the beam for the access of required tumor therapy field. The origin data plan comes from treatment control system. Two set of dipole magnet is driven for changing the beam path. Meanwhile, interfaces between scanning system and other systems is built for beam control and safe considering. In order to acquire high precise feedback control, the beam position and dose monitor ionization chambers will be constructed in the nozzle. Once accident occurs, the scanning system should be able to response instantly to cut off beam and inform safe interlock system simultaneously. The response time of scanning system is at tens of microsecond level, so the scanning controller, feedback controller and the monitor electronics is built in fast mode. Detailed description will be presented in this paper.  
poster icon Poster TUPC10 [0.794 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPC10  
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TUPC13 Early Commissioning of the Luminosity Dither Feedback for SuperKEKB luminosity, MMI, controls, electron 328
 
  • M. Masuzawa, Y. Funakoshi, T. Kawamoto, S. Nakamura, T. Oki, M. Tobiyama, S. Uehara
    KEK, Ibaraki, Japan
  • P. Bambade, S. Di Carlo, D. Jehanno, C.G. Pang
    LAL, Orsay, France
  • D.G. Brown, A.S. Fisher, M.K. Sullivan
    SLAC, Menlo Park, California, USA
  • D. El Khechen
    CERN, Geneva, Switzerland
  • U. Wienands
    ANL, Argonne, Illinois, USA
 
  SuperKEKB is an electron-positron collider, which aims to achieve a peak luminosity of 8×1035 cm-2 s−1 using what is known as the "nano-beam" scheme. This paper reports on the commissioning and performance of a luminosity dither feedback. The system, based on one previously used at SLAC for PEP-II, is employed for collision orbit feedback in the horizontal plane. Twelve air-core Helmholtz coils drive the positron beam sinusoidally at a frequency near 80 Hz, forming a closed bump at the interaction point. A lock-in amplifier detects the amplitude and phase of the corresponding frequency component of the luminosity signal. When the beams are aligned for peak luminosity, the magnitude of the luminosity component at the dithering frequency becomes zero. The magnitude grows as the beams are offset, and the phase shifts by 180 degrees when the direction of the necessary correction reverses. The hardware and algorithm were tested during SuperKEKB Phase II run. The electron beam orbit was successfully adjusted to minimize the amplitude of the dither frequency component of the luminosity signal, and the optimal condition was maintained by continuously adjusting the electron beam orbit.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPC13  
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WEPA01 A MicroTCA.4 Timing Receiver for the Sirius Timing System timing, controls, interface, hardware 375
 
  • J.L. Brito Neto, G.B.M. Bruno, S.R. Marques, L.M. Russo, D.O. Tavares
    LNLS, Campinas, Brazil
 
  The AMC FMC carrier (AFC) is a MicroTCA.4 AMC board which has a very flexible clock circuit that enables any clock source to be connected to any clock input, including telecom clock, FMC clocks, programmable VCXO oscillator and FPGA. This paper presents the use of the AFC board as an event receiver connected to the Sirius timing system to provide low jitter synchronized clocks and triggers for Sirius BPM electronics and other devices.  
poster icon Poster WEPA01 [3.299 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA01  
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WEPB06 Time-Synchronous Measurements of Transient Beam Dynamics at Spear3* diagnostics, controls, experiment, injection 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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