TY - CPAPER AU - Wang, G.L. AU - Dai, D.X. AU - Wu, G.R. AU - Yang, X.M. AU - Zhang, W.Q. TI - Operating of SXFEL in a Single Stage High Gain Harmonic Generation Scheme J2 - Proc. of FEL2015 AB - The beam energy spread at the entrance of undulator system is of paramount importance for efficient density modulation in high-gain seeded free-electron lasers (FELs). In this paper, the dependencies of high harmonic bunching efficiency in the high-gain harmonic generation (HGHG) schemes on the electron energy spread distribution are studied. Theoretical investigations and multi-dimensional numerical simulations are applied to the cases of uniform and saddle beam energy distributions and compared to a traditional Gaussian distribution. It shows that the uniform and saddle electron energy distributions significantly enhance the performance of HGHG-FELs. A numerical example demonstrates that, with the saddle distribution of sliced beam energy spread controlled by a laser heater, the 30th harmonic radiation can be directly generated by a single-stage seeding scheme for a soft x-ray FEL facility. PB - JACoW CY - Geneva, Switzerland SP - 29 EP - 33 KW - laser KW - bunching KW - FEL KW - electron KW - linac DA - 2015/12 PY - 2015 SN - 978-3-95450-134-2 DO - 10.18429/JACoW-FEL2015-MOC04 UR - http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/moc04.pdf ER -