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Zheng, S.

Paper Title Page
MPPP026 Development of Longitudinal Coupling Impedance Measurement Platform for BEPCII 1940
 
  • G. Huang, W.-H. Huang, S. Zheng
    Tsinghua University, Beijing
  • J.Q. Wang, D.M. Zhou
    IHEP Beijing, Beijing
  
  Funding: Supported by NSFC 10375035.

A coaxial line impedance measurement platform is developed for BEPCII. A pair of gradual change impedance matching section is designed and fabricated by numerical control milling machine. The special designed RF connector is applied to strengthen the inner conductor. The algorithm of TRL calibration is applied in the system to avoid the usage of a reference pipe for each device under test. The measurement is accomplished by a VNA under the control of the software written in LabView.

 
WPAT011 Application of TRL Calibration in Longitudinal Coupling Impedance Measurement Platform for BEPCII 1225
 
  • G. Huang, W.-H. Huang, S. Zheng
    Tsinghua University, Beijing
  • D.M. Zhou
    IHEP Beijing, Beijing
  
  Funding: Supported by NSFC 10375035.

TRL calibration is one of the standard calibration methods for RF measurement. Applying the TRL calibration method into the longitudinal coupling impedance platform makes it possible to eliminate the error matrix of the matching section and the RF connector. By using TRL calibration in the platform, the reference pipe of each device under test no longer required. The formula of the calibration is discussed in this paper and the software based on it is introduced.

 
TPPE065 Calculating of Coupling Factor of Microwave Electron Gun 3656
 
  • X. Bian, H. Chen, S. Zheng
    TUB, Beijing
  • D. Li
    LBNL, Berkeley, California
  
  To design the coupler of a designing microwave electron gun, we use the "energy method" proposed by Derun Li, et al. The intrinsic Q of the electron gun cavity is very high: about 20000. The method calculates the intrinsic and external Q values of a cavity coupled to a waveguide using MAFIA code in time domain. The comparisons between simulation and experimental results are given for a set of different coupling iris apertures and height. The result shows that "energy method" works efficiently for high Q cavities.  
WPAT093 A Three-Cell Superconducting Deflecting Cavity Design for the ALS at LBNL 4287
 
  • J. Shi, H. Chen, S. Zheng
    TUB, Beijing
  • J.M. Byrd, D. Li
    LBNL, Berkeley, California
  
  Deflecting RF cavities can be used to generate sub-pico-second x-rays by creating correlations between longitudinal and transverse phase space of electron bunches in radiation devices. Up to 2-MV defecting voltage at 1.5-GHz is required for 1.9-GeV electron beam at the Advanced Light Source (ALS) at LBNL. We present a conceptual design for a 1.5-GHz three-cell superconducting RF cavity and its coupler. The cavity geometry and deflecting shunt impedance are optimized using MAFIA code. The cavity impedance from lower and higher order modes (LOM and HOM) are computed. Possible schemes for damping most harmful LOM and HOM modes are discussed and simulated.  
RPAT097 2-D Low Energy Electron Beam Profile Measurement Based on Computer Tomography Algorithm with Multi-Wire Scanner 4323
 
  • N.J. Yu, K.Y. Gong, Q. F. Li, C.-X. Tang, S. Zheng
    TUB, Beijing
  
  A new method for low energy electron beam profile measurement is advanced, which presents a full 2-D beam profile distribution other than the traditional 2-D beam profile distribution given by 1-D vertical and horizontal beam profiles. The method is based on the CT (Computer Tomography) algorithm. Multi-sets of data about the 1-D beam profile projections are attained by rotating the multi-wire scanner. Then a 2-D beam profile is reconstructed from these projections with CT algorithm. The principle of this method is presented. The simulation and the experiment results are compared and analyzed in detail.