Author: Yuan, R.X.
Paper Title Page
MOPC17 On-line Crosstalk Measurement and Compensation Algorithm Study of SXFEL Digital BPM System 150
 
  • F.Z. Chen, L.W. Lai, Y.B. Leng, T. Wu, L.Y. Yu
    SSRF, Shanghai, People's Republic of China
  • J. Chen, R.X. Yuan
    SINAP, Shanghai, People's Republic of China
 
  Shanghai soft X-ray Free Electron Laser (SXFEL) has acquired the custom designed Digital BPM processor used for signal processing of cavity BPMs and stripline BPMs. In order to realize monitor the beam position accurately, it has high demand for DBPM system performance. Considering the crosstalk may introduce distortion and influence beam position resolution, it is important to analyze and compensate the crosstalk to improve the resolution. We choose the CBPM signal to study the crosstalk for its narrowband and sensitive for phase. The main experiment concept is successive accessing four channels to form a signal transfer matrix, which including amplitude frequency response and phase response information. And the compensation algorithm is acquire four channel readouts, then using the signal transfer matrix to reverse the true signal to ensure the accurate beam position measurement. This concept has already been tested at SXFEL and hopeful to compensate the crosstalk sufficiently.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPC17  
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TUPB09 The Evaluation of Beam Inclination Angle on the Cavity BPM Position Measurement 278
 
  • J. Chen, L.W. Lai, Y.B. Leng, L.Y. Yu, R.X. Yuan
    SINAP, Shanghai, People's Republic of China
 
  Cavity beam position monitor (CBPM) is widely used to measure the transverse position in free-electron laser (FEL) and international linear collider (ILC) facilities due to the characteristic of high sensitive. In order to study the limiting factors of the position resolution of cavity BPM, the influence of beam inclination angle on the measure-ment of CBPM position and the direction of beam deflec-tion was analyzed. The simulation results show that the beam inclination angle is an important factor limiting the superiority of CBPM with extremely high position resolu-tion. The relative beam experiments to change the relative inclination angle between the cavity and the electron beam based on a 4-dimension moveable platform were performed in Shanghai Soft X-ray FEL (SXFEL) facility, the experiment results will also be mentioned as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB09  
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WEOA04 The Application of Beam Arrival Time Measurement at SXFEL 342
 
  • S.S. Cao, J. Chen, Y.B. Leng, R.X. Yuan
    SINAP, Shanghai, People's Republic of China
 
  Shanghai soft X-ray free electron laser (SXFEL) is able to generate high brightness and ultra-short light pulses. The generation of the light sources relies on the synchronization between seeded laser and electron bunch. Beam arrival time play an important role to keep the synchronization. For the SXFEL, a beam arrival time resolution under 100 fs is required. In this paper, the application of beam arrival time measurement scheme on SXFEL has been presented. The whole BAM system consists of four parts: beam arrival time monitor, electronic front-end, signal acquisition system, and high-level signal processing and presentation. Currently, four sets of beam arrival time monitors (BAMs) have been installed in the SXFEL and distributed in four different locations. The relevant beam arrival time experiment and beam flight time experiment based on the dual-cavities mixing method have also been performed so as to evaluate and analyze the beam status.  
slides icon Slides WEOA04 [4.588 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEOA04  
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WEPA13 Electro-Optic Modulator Based Beam Arrival Time Monitor for SXFEL* 396
 
  • X.Q. Liu, L.F. Hua, L.W. Lai, Y.B. Leng, R.X. Yuan
    SINAP, Shanghai, People's Republic of China
  • N. Zhang
    SSRF, Shanghai, People's Republic of China
 
  Beam arrival time monitor (BAM) is an important tool to investigate the temporal characteristic of elec-tron bunch in free electron laser (FEL) like Shanghai soft X-ray Free Electron Laser (SXFEL). Since the timing jitter of electron bunch will affect the FEL's stability and the resolution of time-resolved experi-ment at FELs, it is necessary to precisely measure the electron bunch arrival time so as to reduce the timing jitter of the electron bunch with beam based feedback. The beam arrival time monitor based on electro-optic modulator (EOM) is already planned and will be de-veloped and tested at SXFEL in the next three years. Here the design and preliminary results of the EOM based beam arrival time monitor will be introduced in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA13  
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