Author: Chen, H.
Paper Title Page
MOPPP008 Hard X-ray Generation Experiment at Tsinghua Thomson Scattering X-Ray Source 583
  • Y.-C. Du, H. Chen, Q. Du, Hua, J.F. Hua, W.-H. Huang, H.J. Qian, C.-X. Tang, H.S. Xu, L.X. Yan, Z. Zhang
    TUB, Beijing, People's Republic of China
  Recently, there is increasing industrial and scientific interesting in ultra-fast, high peak brightness, tunable energy and polarization, monochromatic hard X-ray source. The X-ray source based on the Thomson scattering between the relativistic electron beam and TW laser pulse is the suitable candidate for its compact and affordable alternatives for high brightness hard monochromatic X-ray generation. Accelerator laboratory in Tsinghua University al so proposed and built Tsinghua Thomson scattering X-ray source. The hard x-ray pulse has been generated in experiment with 47 MeV electron and 20 TW laser in this year, and the parameters of the X-ray have been measured preliminarily. The experimental results are presented and discussed in this paper.  
TUPPD069 Schottky-Enabled Photoemission and Dark Current Measurements - Toward an Alternate Approach to Fowler-Nordheim Plot Analysis 1563
  • E.E. Wisniewski, W. Gai, J.G. Power
    ANL, Argonne, USA
  • H. Chen, Y.-C. Du, Hua, J.F. Hua, W.-H. Huang, C.-X. Tang, L.X. Yan, Y. You
    TUB, Beijing, People's Republic of China
  • A. Grudiev, W. Wuensch
    CERN, Geneva, Switzerland
  • E.E. Wisniewski
    Illinois Institute of Technology, Chicago, Illinois, USA
  Field-emitted dark current, a major gradient-limiting factor in RF cavities, is usually analyzed via Fowler-Nordheim (FN) plots. Traditionally, field emission is attributed to geometrical perturbations on the bulk surface whose field enhancement factor (beta) and the emitting area (A) can be extracted from the FN plot. Field enhancement factors extracted in this way are typically much too high (1 to 2 orders of magnitude) to be explainable by either the geometric projection model applied to the measured surface roughness or by field enhancement factors extracted from Schottky-enabled photoemission measurements. We compare traditional analysis of FN plots to an alternate approach employing local work function variation. This is illustrated by comparative analysis of recent dark current and Schottky-enabled photoemission data taken at Tsinghua S-band RF gun. We conclude by describing a possible experimental plan for discrimination of variation of local work function vs. local field enhancement.  
TUPPR015 Choke-Mode Damped Structure Design for the CLIC Main Linac 1840
  • H. Zha, H. Chen, W.-H. Huang, C.-X. Tang
    TUB, Beijing, People's Republic of China
  • A. Grudiev, J. Shi, W. Wuensch
    CERN, Geneva, Switzerland
  Choke-mode damped accelerating structures are being studied as an alternative to the CLIC waveguide damped baseline structure. Choke-mode structures hold the potential for much lower pulsed surface heating and reduced cost since no milling is required. We propose a new choke geometry which has significant suppression of higher order dipoles. By impedance matching and detuning of the first dipole pass-band, the wakefield suppression is comparable to the baseline design with waveguide damping. A fully featured choke mode structure with the same accelerating gradient profile and filling time as the nominal CLIC design has been designed. It has the potential to replace the waveguide damped design without changing any of the machine layout or the beam parameters.  
THPPC074 High Frequency High Power RF Generation using a Relativistic Electron Beam 3458
  • C.-J. Jing, S.P. Antipov, A. Kanareykin, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • H. Chen, Y. Yang
    TUB, Beijing, People's Republic of China
  • M.E. Conde, W. Gai, J.G. Power
    ANL, Argonne, USA
  High frequency, high power rf sources are required for many applications. Benefiting from the ~10 GW beam power provided by the high current linac at the Argonne Wakefield Accelerator facility, we propose to develop a series of high power rf sources based on the extraction of coherent Cherenkov radiation from the relativistic electron beam. The frequencies cover from C-band up to W-band with different structures. Simulations show that ~1 GW 20 ns rf pulse can be generated for an 11.7 GHz structure, ~400 MW for a 26 GHz structure, and ~14 MW for a 91 GHz structure.  
THPPR050 Fabrication and High Power RF Test of A C-band 6MeV Standing-wave Linear Accelerating Structure 4089
  • J.H. Shao, H. Chen, H. Zha
    TUB, Beijing, People's Republic of China
  We have designed a C-band standing-wave bi-periodic on-axis coupled linear accelerating structure for industrial and medical applications [1]. The output electron energy is 6MeV and the pulse current intensity is 100mA. The structure has been fabricated and measured in cold test. The cold test results show a good agreement between the simulation and actual measurement. At present, it’s under high power RF test. In this paper, we illustrate the fabrication, the results of cold test and newly high power RF test.