Author: Bambade, P.
Paper Title Page
TUZGBD5 Performance of Nanometre-Level Resolution Cavity Beam Position Monitors at ATF2 1212
 
  • T. Bromwich, D.R. Bett, N. Blaskovic Kraljevic, R.M. Bodenstein, P. Burrows, G.B. Christian, C. Perry, R.L. Ramjiawan
    JAI, Oxford, United Kingdom
  • S. Araki, A. Aryshev, T. Tauchi, N. Terunuma
    KEK, Ibaraki, Japan
  • P. Bambade, S. Wallon
    LAL, Orsay, France
  • S.W. Jang
    Korea University Sejong Campus, Sejong, Republic of Korea
 
  A system of three low-Q cavity beam position monitors (BPMs), installed in the interaction point (IP) region of the Accelerator Test Facility (ATF2) at KEK, has been designed and optimised for nanometre-level beam position resolution. The BPMs are used to provide an input to a low-latency, intra-train beam position feedback system deployed in single-pass, multi-bunch mode with the aim of demonstrating intra-train beam stabilisation on electron bunches of charge ~1 nC separated in time by 280 ns. In 2016 the BPM resolution was demonstrated to be below 50 nm using the raw measured vertical positions at the three BPMs. New results will be presented utilising integrated sampling of the raw waveforms, improved BPM alignment and modified cavities to demonstrate a vertical position resolution on the order of 20 nm.  
slides icon Slides TUZGBD5 [8.561 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUZGBD5  
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WEPAL037 Simulation Study on Luminosity Feedback for Horizontal Beam Stabilization at Superkekb 2250
 
  • C.G. Pang, P. Bambade
    LAL, Orsay, France
  • Y. Funakoshi, S. Uehara
    KEK, Ibaraki, Japan
 
  The SuperKEKB e+ e- collider uses highly focused ultra-low emittance bunches colliding every 4 ns to reach a very high luminosity of 8× 1035 cm-2s-1. It is quite essential to have an orbit feedback system at the Interaction Point (IP) to maintain the optimum overlap between the colliding beams in the presence of ground motion disturbances. For the horizontal motion, a luminosity monitoring system, based on measuring the rate of the Bhabha process at vanishing scattering angle, is developed as input signal to the feedback system. The relative precision needed for this monitor is studied in detail, for the different successive stages of luminosity operation, based on a full simulation of this system, including the detector, DAQ, lock-in amplifier, and feedback control.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL037  
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WEPAL038 First Tests of Superkekb Fast Luminosity Monitors During 2018 Phase-2 Commissioning 2254
 
  • 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
 
  The SuperKEKB e+e- collider aims to reach a very high luminosity of 8× 1035 cm-2s-1, by using highly focused ultra-low emittance bunches colliding every 4 ns, it is essential to have an orbit feedback system at the Interaction Point (IP) to maintain the optimum overlap between two colliding beams. Luminosity monitoring systems including LumiBelle2 and ZDLM as input to dithering feedback system used to stabilize the horizontal orbit at the IP were developed and will be described, including the detectors, mechanical set-up, DAQ. Preliminary measurements and analysis of background and first stage luminosity monitoring data collected will be reported and compared with simulation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL038  
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THYGBE4 Early Phase 2 Results of LumiBelle2 for the SuperKEKB Electron Ring 2934
 
  • S. Di Carlo, P. Bambade, D. Jehanno, V. Kubytskyi, C.G. Pang, Y. Peinaud, C. Rimbault
    LAL, Orsay, France
 
  We report on the early SuperKEKB Phase 2 operations of the fast luminosity monitor (LumiBelle2 project). Fast luminosity monitoring is required by the dithering feedback system, which is used to stabilize the beam in the presence of horizontal vibrations. In this report, we focus on the operations related to the electron side of LumiBelle2. Diamond sensors are located 30 meters downstream of the IP, just above, beside, and below the electron beam pipe. During early Phase 2, the sensors are used to measure the background, arising from beam-gas scattering. We present the hardware design, the detection algorithm, and the analysis of the background measurements taken up-to-date. The results are then compared with a detailed simulation of the background, in order to well understand the physical processes involved. The simulation is performed using SAD for generation and tracking purposes, while Geant4 is used to calculate the energy deposition in the diamond sensors.  
slides icon Slides THYGBE4 [3.096 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBE4  
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