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Title: Reversible beam heater for suppression of microbunching instability by transverse gradient undulators

The microbunching instability driven by beam collective effects in a linear accelerator of a free-electron laser (FEL) facility significantly degrades the electron beam quality and FEL performance. A conventional method to suppress this instability is to introduce an additional uncorrelated energy spread by laser-electron interaction, which has been successfully operated in the Linac Coherent Light Source and Fermi@Elettra, etc. Some other ideas are recently proposed to suppress the instability without increasing energy spread, which could benefit the seeded FEL schemes. In this paper, we propose a reversible electron beam heater using two transverse gradient undulators to suppress the microbunching instability. This scheme introduces both an energy spread increase and a transverse-to-longitudinal phase space coupling, which suppress the microbunching instabilities driven by both longitudinal space charge and coherent synchrotron radiation before and within the system. Finally the induced energy spread increase and emittance growth are reversed. In conclusion, theoretical analysis and numerical simulations are presented to verify the feasibility of the scheme and indicate the capability to improve the seeded FEL radiation performance.
 [1] ;  [2] ;  [3] ;  [4]
  1. Univ. of Chinese Academy of Science, Beijing (China); SLAC National Accelerator Lab., Menlo Park, CA (United States); Chinese Academy of Sciences, Shanghai (China)
  2. SLAC National Accelerator Lab., Menlo Park, CA (United States); Peking Univ., Beijing (China)
  3. Chines Academy of Sciences, Shanghai (China)
  4. SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Grant/Contract Number:
PHY-1535215; AC02-76SF00515; 2016YFA0401900
Published Article
Journal Name:
Physical Review Accelerators and Beams
Additional Journal Information:
Journal Volume: 20; Journal Issue: 8; Journal ID: ISSN 2469-9888
American Physical Society (APS)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1390303