TY - CPAPER
AU - Zhang, Z.
AU - Ding, Y.
AU - Fawley, W.M.
AU - Huang, Z.
AU - Krzywinski, J.
AU - Lutman, A.A.
AU - Marcus, G.
AU - Marinelli, A.
AU - Ratner, D.F.
TI - Microbunching-Instability-Induced Sidebands in a Seeded Free-Electron Laser
J2 - Proc. of FEL2015
AB - The measured, self-seeded soft X-ray radiation spectrum corresponding to multiple effective undulator lengths of the LCLS exhibits a pedestal-like distribution around the seeded frequency. In the absence of a post-undulator monochromator, this contamination limits the spectral purity and may seriously degrade certain user applications. In general for either externally- or self-seeded FELs, such pedestals may originate with any time-varying property of the electron beam that can modulate the complex gain function. In this paper we specifically focus on the contributions of electron beam microbunching prior to the undulator. We show that both energy and density modulations can induce sidebands in a seeded FEL configuration. Analytic FEL theory and numerical simulations are used to analyze the sideband content relative to the amplified seeded signal, and to compare with experimental results.
PB - JACoW
CY - Geneva, Switzerland
SP - 741
EP - 745
KW - undulator
KW - FEL
KW - simulation
KW - electron
KW - bunching
DA - 2015/12
PY - 2015
SN - 978-3-95450-134-2
DO - 10.18429/JACoW-FEL2015-WEP084
UR - http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/wep084.pdf
ER -