Dogleg Bunch Compressor Design for Compensation of Nonlinear Energy Chirps up to Second Order
Wai-Keung Lau1*, Chia-Hsiang Chen1, San-You Teng2, An-Ping Lee1
1Light Source Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
2Physics Department, National Tsing Hua University, Hsinchu, Taiwan
* Presenter:Wai-Keung Lau,
A 250 MeV linac system has been designed to provide a high brightness electron beam for the proposed NSRRC THz/EUV free electron laser (FEL) facility. This system is equipped with a so-called ‘dogleg’ bunch compressor with linearization optics that is able to compensate nonlinear energy chirps introduced into the beam by the chirper linac rf voltage up to second order. In this study, beam optics design of the compressor is started with accelerator beam optics code – MAD, then followed by ELEGANT simulation for optimization of electron distribution in 6D phase-space. In such particle tracking simulation, the effects of coherent synchrotron radiation (CSR), longitudinal space charge (LSC), and linac wake fields have been considered. Start-to-end simulation to illustrate the capability of this linac system to generate a beam that can be used to drive a seeded EUV FEL to saturation within reasonable undulator length. It has been demonstrated that, for a 200 pC beam, such FEL has a saturated output power of ~270 MW at 2-m undulator length.

Keywords: Free electron laser, High brightness electron beam, Bunch compressor