TU1P —  Plenary Session 6   (18-Sep-18   14:00—15:00)
Chair: D. Raparia, BNL, Upton, Long Island, New York, USA
Paper Title Page
TU1P01 Extreme High Brightness Electron Beam Generation in a Space Charge Regime 314
  • A. Bacci
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  • L. Faillace, M. Rossetti Conti
    Universita’ degli Studi di Milano & INFN, Milano, Italy
  The generation of ultra-short, low emittance and low energy spread electron bunches is nowadays a critical requirement for accelerators in plasma wave or for femto-second light sources. A new longitudinal compression scheme, based on velocity and ballistic bunching tech-niques in presence of space charge forces, allows to enter in a peculiar regime, so-called laminar bunching (LB). In this regime, the bunch is longitudinally compressed, at the expense of its transverse size, and the over-bunching is forbidden by the laminarity: going to the minimal longi-tudinal dimension the bunch is adiabatically frozen and transversally refocused. Furthermore this technique heats slightly the uncorrelated energy spread resulting in elec-tron distributions that, in case of bending paths, does not require Laser Heater devices.  
slides icon Slides TU1P01 [1.720 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU1P01  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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Interaction of electron beam with dielectric wakefield structure at TTX beamline  
  • D. Wang
    TUB, Beijing, People’s Republic of China
  Dielectric wakefield structure (DWS) find applications in many fields such as radiation source, wakefield acceleration, electron beam manipulations. Interaction of electron beam with dielectric wakefield structure is one of the hot topic. We have performed series of experiments on beam interaction with DWS at the TTX beamline, including experiment on the THz radiation, selectively excitation of THz by bunch train, and collinear wakefield acceleration with two beam interferometry method. This talk will give the details on the experimental results.  
slides icon Slides TU1P02 [3.338 MB]  
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Observation of Resonant Coherent Diffraction Radiation from a Multi-bunch Electron Beam Passing Through an Optical Cavity  
  • Y. Honda, A. Aryshev, R. Kato, T. Miyajima, T. Obina, M. Shimada, R. Takai, T. Uchiyama, N. Yamamoto
    KEK, Ibaraki, Japan
  • T. Hotei
    Sokendai, Ibaraki, Japan
  Funding: This work was supported by JSPS KAKENHI Grant Number 16H05991.
Energy Recovery Linac can realize a linac-type beam at a high current. An ERL test accelerator, cERL, has been constructed in KEK. Utilizing these features of the ERL beam, low emittance, short bunch, and high repetition rate, we have been developing a unique terahertz radiation source of resonant coherent diffraction radiation. An optical resonant cavity consists of two concave mirrors with a beam hole at the center was installed in the return-loop of cERL. When the multi-bunch electron beam passes through the cavity, it radiates coherent diffraction radiation in the cavity. If the round-trip time of the cavity precisely matches the beam repetition, the radiation of the bunches are stacked coherently and stimulates the energy conversion process from the beam to the radiation. Measuring the terahertz radiation power while scanning the cavity length, we observed a sharp resonance peak showing the realization of the stimulated emission. The cavity was carefully designed to tune the carrier-envelope-offset to be zero. It allows to excite wide-band longitudinal modes simultaneously, and realize a mode-locked terahertz pulse.
slides icon Slides TU1P03 [1.740 MB]  
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