Author: Lin, L.
Paper Title Page
MOPAB084 Online Measurement of Electrode Gains for Stripline Beam Position Monitor in the HLS II Storage Ring 316
 
  • F.F. Wu, L. Lin, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, J.G. Wang, J.H. Wei, Y.L. Yang, T.Y. Zhou, Z.R. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Funding: Supported by the National Key Research and Development Program of China(No. 2016YFA0402000) and the National Science Foundation of China (11575181, 11605202)
Three axially symmetric stripline beam position monitors were installed in the HLS II storage ring and each stripline BPM was machined with button BPM together. Due to mechanical errors of stripline BPM, differences in electrode gains will lead to measurement error for beam position and mutual coupling between beam horizontal position and vertical position. So it is very important to calibrate electrode gains for axially symmetric BPM. A method was proposed to calibrate electrode gains of this kind of BPM. This method is suitable for all axially symmetric BPMs, whether stripline BPM or button BPM. The online calibrated gains were compared with offline calibrated gains and the results have shown that online and offline calibrated electrode gains were basically consistent.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB084  
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MOPAB085 Introduction of Beam Position Monitor System in the HLS II Storage Ring 319
 
  • F.F. Wu, L. Lin, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, J.G. Wang, J.H. Wei, K. Xuan, Y.L. Yang, T.Y. Zhou, Z.R. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Funding: Supported by the National Key Research and Development Program of China (No. 2016YFA0402000) Supported by the National Science Foundation of China (11575181, 11605202)
Beam position monitor(BPM) system for the HLS II storage ring were designed in the HLS II upgrade project. This system is composed of BPM, BPM processor embedded with IOC and OPI. Every component of BPM system is introduced in this paper. BPM processors have different modes of data, such as ADC data, turn-by-turn(TBT) data, fast acquirement(FA) data and slow acquirement(SA) data. Different modes of data are used to different applications. Two applications based on SA data of the BPM system, such as BBA for quadrupole magnet center measurement and beam closed orbit feedback, are described in detail. The result of BBA shows that most magnetic centers of quadrupole magnets are in the range of [-1 mm, 1 mm] with respect to BPM electric centers. The result of beam closed orbit feedback shows that beam orbit stability when the closed orbit feedback system is on is far better than that when the closed orbit feedback system is off.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB085  
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TUPIK064 Application of Smoothing Analysis in the Alignment and Installation Process of Particle Accelerator 1839
 
  • W. Wang, X.Y. He, L. Lin, F.F. Wu, Q. Zhang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  With the development of technology and theory of particle accelerator, the new particle accelerators will be built in the near future. Comparing with the running accelerators, higher efficiency and accuracy of installation and alignment are required. It is necessary for all the storage ring magnets to be placed with a high relative accuracy to meet the stringent demands of accelerator physics. Smoothing analysis is a practical method considering both relative accuracy and work efficiency. This article mainly introduces the principle and application of smoothing analysis.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK064  
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THPAB123 Low Level RF Control System Architecture OF IR-FEL 4014
 
  • B. Du, G. Huang, L. Lin, W. Liu, Z.R. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Infrared free electron laser (IR-FEL) is one type of laser driven by accelerator and generated by undulator. It is built by National Synchrotron Radiation Laboratory (NSRL). Compared to synchrotron radiation light source, it have much higher demand of beam quality. Low level RF control system (LLRF) need to reach higher controlled accuracy corresponded to the demand. Accelerating structure which contains one pre-buncher, one buncher and two accelerating tube can accelerate beam to 60MeV. Frequency distribution system use direct digital synthesizer technology to generate 5 signal of different frequency. LLRF system detect 8 channels signal, one for control loop, and the others for monitor and interlock. The hardware contain MTCA.4 architecture which is advanced in global; RF board for downconverter and IQ modulation output; DSP board for sampling, controller and transmission.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB123  
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THPAB124 DSP Frame and Algorithm of LLRF of IR-FEL 4017
 
  • B. Du, G. Huang, L. Lin, W. Liu, Z.R. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Infrared Free Electron Laser (IR-FEL) use linear accelerator to accelerate electron to relative speed and then generate simulated radiation of infrared wavelength by periodic magnetic field of undulator. The amplitude and phase of microwave field need to be controlled precisely by low level RF control system (LLRF) to meet the high quality demand of electron from undulator. This paper mainly introduce the digital signal processing frame and feedback algorithm. Four times frequency sampling can realize IQ demodulation precisely and reduce DC offset, amplitude sampling error is less than 0.075% and phase sampling error is less than 0.1°. Pipeline CORDIC can calculate amplitude and phase by parallel processing and shift operation. Phase calculating accuracy reach 0.0005° when iteration count is 18. FIR filter is used to improve frequency selected performance. Feedback loop use digital PI controller to adjust system output.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB124  
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THPAB127 Development of 1.3 GHz Cavity Combiner for 24 kW CW SSA 4020
SUSPSIK107   use link to see paper's listing under its alternate paper code  
 
  • W. Liu, B. Du, G. Huang, L. Lin, L. Shang, W.B. Song
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  The 24KW CW SSA (Solid-State Amplifier) is being developed to drive the 1.3GHz SC Linac used in a THz light source. The SSA adopts the compact all-in-one combining method ' cavity combiner, which is proposed and developed in recent years. This paper reports the R&D of the cavity combiner. The cavity combiner resonates in TM010 mode, coupling with 24 coaxial-connected 1kW amplifier modules. The cavity's electromagnetic characteristic is calculated by CST, and the mechanical structure including the input and output coupler has been designed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB127  
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THPIK063 The RF System of Infrared Free Electron Laser Facility at NSRL 4239
 
  • L. Lin, B. Du, G. Huang, K. Jin, F.F. Wu
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Funding: The Natural Science Foundation of China
An infrared free electron laser light source (IRFEL) is being constructed at National Synchrotron Radiation Laboratory, which could be used in the study of far infrared detection, light dissociation and light excitation. The accelerator of IRFEL deliver a average current 300 A electron beam at 15~60 MeV, the energy spread is less than 240 keV, and the emittance is less than 30 mm*mrad. IRFEL is consisted of two optical resonator system, which could create 2.5~50 um, 40~200um infrared laser respectively. The design of IRFEL RF system is introduced, the recent progress of prebuncher, buncher, frequency distribution, accelerator and DLLRF system are also present in this paper.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK063  
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THPVA057 The Primary Control Network of HLS II 4573
 
  • W. Wang, L. Lin, F.F. Wu, Q. Zhang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  To meet the accuracy requirement of alignment and installation of HLS', the high accuracy control network is necessary. The high accuracy primary control network will provides reliable reference to the local control network. After optimization design that using Monte-Carlo method, according to the structure characteristic of HLS', the primary control network is measured by several different instruments, such as: Laser tracker, Total station and plummet. The accuracy of actual primary control network meets the design requirements, it provides strong foundation for subsequent project.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA057  
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