Author: Sugimoto, H.
Paper Title Page
MOPGW031 Analysis and Correction for the Effect of Multipoles with Skewed Errors on IP Beam Dynamics in SuperKEKB 159
SUSPFO039   use link to see paper's listing under its alternate paper code  
 
  • K. Hirosawa
    Sokendai, Ibaraki, Japan
  • Y. Funakoshi, H. Koiso, A. Morita, K. Ohmi, Y. Ohnishi, H. Sugimoto, D. Zhou
    KEK, Ibaraki, Japan
 
  The beam dynamics at the interaction point (IP) in the accelerators which has the nano-beam scheme like as SuperKEKB is extremely sensitive for skewed error of final focusing magnets (QCS). As proceeding the beta squeezing in the interaction region (IR), the effect of optics aberrations at IP is enhanced. In the SuperKEKB Phase-2 commissioning, there was the problem come from skewed quadrupole fields in IR. The dominant skew parameters ‘‘R" for this problem is very hard to see directly by using beam position monitors, thus it was corrected by scanning R parameters. In the next commissioning Phase-3 which is just before the operation with the Belle II experiment, it is planned that the IP beta squeezing is going forward to design parameters which is smaller than it achieved in Phase-2 by the factor of 4 (for horizontal beta) and 10 (for vertical beta). Hence the effect of skew error will be considerable larger and it is estimated that skew sextupoles will emerge as a serious cause for the aberration from the orbit. This report is the study of analysis and correction results for the effect of QCS skewed errors in the SuperKEKB commissioning.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW031  
About • paper received ※ 19 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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TUZPLM2 Optics Measurements at SuperKEKB Using Beam Based Calibration for BPM and BBA 1198
 
  • H. Sugimoto, H. Koiso, K. Mori, A. Morita, Y. Ohnishi, M. Tejima
    KEK, Ibaraki, Japan
 
  The beam-based calibration(BBC) technique for Beam-Position-Monitor(BPM) is applied in order to establish reliable optics measurement. In the BBC, a response model between beam position, charge and output signals of the BPM electrodes are introduced to calibrate the relative gain of the BPM electrodes. The gains are adjusted by total squares fitting so that the model reproduces the measured BPM signals. The Beam-Based Alignment(BBA) is also performed to determine the magnetic center of a quadrupole. Using BBC and BBA, the performance of the BPM system and optics correction are successfully improved. This talk presents what we experienced during the beam commissioning focusing on beam optics measurement and some details on the beam-based calibration scheme for BPM system.  
slides icon Slides TUZPLM2 [15.911 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZPLM2  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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