Linear Microbunching Gain Estimation Including CSR, LSC And Linac Geometric Impedances In Recirculation Arcs

Conference · Tue Sep 01 00:00:00 EDT 2015

DOI:https://doi.org/10.18429/JACoW-ERL2015-TUICLH2034· OSTI ID:1972310

Tsai, C. -Y. ^[1]; Douglas, D. ^[2]; Li, R. ^[2]; Tennant, C. ^[2]

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1. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

It is known that microbunching instability (MBI) has been one of the most challenging issues with the design of magnetic compressor chicanes for X-ray FEL or linear colliders, as well as the transport lines for recirculating or energy recovery linacs. To more accurately quantify MBI in a single-pass system and for more complete analyses, we extend our previously developed linear Vlasov solver [1] to incorporate more relevant impedance models into the code, including transient and steady-state coherent synchrotron radiation (CSR), the longitudinal space charge (LSC), and the linac geometric impedance models. Then we self-consistently solve the linearized Vlasov equation for the gain amplification factor. With application of this code to two specially designed recirculation arcs [2], the resultant gain functions and spectra are presented and some results are compared with particle tracking simulation by ELEGANT. We also discuss some underlying physics with inclusion of these collective effects. It is anticipated this more complete analysis can further improve the understanding of the MBI mechanisms and shed light on how to suppress or compensate MBI effects in lattice designs. [1] C. -Y. Tsai et al., Theoretical investigation of coherent synchrotron radiation induced microbunching instability in transport and recirculation arcs, Proceedings of FEL 14, available at http://arxiv.org/abs/1408.5542 [2] D. Douglas et al., Control of Coherent Synchrotron Radiation and Micro-Bunching Effects During Transport of High Brightness Electron Beams, JLAB-ACP-14-1751, available at http://arxiv.org/abs/1403.2318 Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1972310
• Report Number(s): JLAB-ACC-15-2332; DOE/OR/23177-6128
• Resource Relation: Conference: 56th ICFA Advanced Beam Dynamics Workshop on Energy Recovery Linacs (ERL 2015) : Stony Brook, NY, USA, June 7-12, 2015
• Country of Publication: United States
• Language: English