Author: Tsai, C.-Y.
Paper Title Page
TUPF13
 Microbunching Instability in Recirculation Arcs  
 
  • C.-Y. Tsai
    Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
  • S.V. Benson, D. Douglas, R. Li, C. Tennant, C.-Y. Tsai
    JLab, Newport News, Virginia, USA
  
  Microbunching instability is one of the most challenging issues in the design of the transport lines for recirculating or energy recovery linac machines. We have developed a linear Vlasov solver to incorporate relevant collective effects, including coherent synchrotron radiation (CSR) and longitudinal space charge (LSC) impedances, for a general linear beamline analysis. With application of this code to two specially designed recirculation arcs * and a circulating cooler ring design of MEIC at Jefferson Lab **, the resultant microbunching gain functions are presented. Some underlying physics with inclusion of these collective effects are discussed. We expect that the analysis can help illustrate the microbunching gain evolution and its spectral response, and further improve the advanced beamline designs.
* D. Douglas et al., http://arxiv.org/abs/1403.2318
** MEIC Design Summary, http://arxiv.org/abs/1504.07961
 
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WEXAUD03
 Space Charge and CSR Microwave Physics in a Circulated Electron Cooler  
 
  • R. Li, S.V. Benson, Y.S. Derbenev, D. Douglas, C. Tennant, Y. Zhang
    JLab, Newport News, Virginia, USA
  • E.W. Nissen
    CERN, Geneva, Switzerland
  • C.-Y. Tsai
    Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
  
  Funding: This work is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Circulator cooler ring (CCR) was proposed * as a scheme to alleviate the high demand for the average current of the cooling beam from the electron source. However, transporting the high-brightness cooling beam through CCR for multiple turns, while preserving the phase space quality of the beam, presents significant challenges for the CCR design **. In this presentation, we describe our studies on the microbunching instability (uBI) induced by the CSR and longitudinal space charge interactions, and present results of microwave physics for a non-magnetized beam circulating in an early design of CCR *** of MEIC. It is envisioned that CCR designed for a magnetized beam will have much reduced microbunching effects. A future plan for such study will be discussed.
* R. Brinkmann, et al., Proc. of EPAC98, p345 (1998)
** C. Tennant and D. Douglas, JLAB-TN-12-027 (2012)
*** C. Tsai et al., this workshop (2015)
 
slides icon Slides WEXAUD03 [2.848 MB]  
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