Author: Marksteiner, Q.R.
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MOC01 Regenerative Amplifier FEL - from IR to X-Rays 20
  • D.C. Nguyen, P.M. Anisimov, C.E. Buechler, Q.R. Marksteiner, R.L. Sheffield
    LANL, Los Alamos, New Mexico, USA
  The Regenerative Amplifier FEL (RAFEL) feeds back a small fraction of the radiation exiting a high-gain undulator as the seed for the next pass, and achieves narrow linewidth and saturation in a few passes. For the IR RAFEL, we used an optical cavity with annular mirrors to reinject ~10% of the IR radiation back into a two-meter undulator [1]. Since then, a number of researchers have proposed RAFEL and XFELO to achieve full temporal coherence in VUV and X-ray FELs [2-5]. For the XFELO, symmetric Bragg backscattering off high-quality diamond crystals can provide very high reflectivity for the XFELO cavity [6]. The required reflectivity for a RAFEL feedback cavity is much lower than the XFELO. We show that 6% feedback is sufficient for the X-ray RAFEL at 9.8 keV to saturate and achieve 0.5-eV bandwidth. We discuss options to out-couple more than ~50% of the RAFEL intra-cavity power and discuss challenges associated with X-ray absorption in the out-coupler.
[1] D. Nguyen et al. NIMA 429 125 (1999)
[2] B. Faatz et al. NIMA A429 424 (1999)
[3] Z. Huang et al. PRL 96 144801 (2006)
[4] B.W.J. McNeil et al. NJP 9 239 (2007)
[5] G. Marcus et al. FEL17 MOP061 (2017)
[6] K. Kim et al. PRL 100 244802 (2008)
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About • paper received ※ 21 August 2019       paper accepted ※ 28 August 2019       issue date ※ 05 November 2019  
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