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Title: Harmonic Self-Seeding for the MaRIE X-ray FEL

Authors:
ORCiD logo [1]; ORCiD logo [1];  [1];  [2]
  1. Los Alamos National Laboratory
  2. SLAC
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1400109
Report Number(s):
LA-UR-17-28665
DOE Contract Number:
AC52-06NA25396
Resource Type:
Conference
Resource Relation:
Conference: NOCE 2017 ; 2017-09-19 - 2017-09-22 ; Arcidosso, Italy
Country of Publication:
United States
Language:
English
Subject:
X-ray Free-Electron Laser

Citation Formats

Nguyen, Dinh Cong, Anisimov, Petr Mikhaylovich, Sheffield, Richard L., and Emma, Claudio. Harmonic Self-Seeding for the MaRIE X-ray FEL. United States: N. p., 2017. Web.
Nguyen, Dinh Cong, Anisimov, Petr Mikhaylovich, Sheffield, Richard L., & Emma, Claudio. Harmonic Self-Seeding for the MaRIE X-ray FEL. United States.
Nguyen, Dinh Cong, Anisimov, Petr Mikhaylovich, Sheffield, Richard L., and Emma, Claudio. 2017. "Harmonic Self-Seeding for the MaRIE X-ray FEL". United States. doi:. https://www.osti.gov/servlets/purl/1400109.
@article{osti_1400109,
title = {Harmonic Self-Seeding for the MaRIE X-ray FEL},
author = {Nguyen, Dinh Cong and Anisimov, Petr Mikhaylovich and Sheffield, Richard L. and Emma, Claudio},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month =
}

Conference:
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  • A longitudinally coherent X-ray pulse from a high repetition rate free electron laser (FEL) is desired for a wide variety of experimental applications. However, generating such a pulse with a repetition rate greater than 1 MHz is a significant challenge. The desired high repetition rate sources, primarily high harmonic generation with intense lasers in gases or plasmas, do not exist now, and, for the multi-MHz bunch trains that superconducting accelerators can potentially produce, are likely not feasible with current technology. In this paper, we propose to place an oscillator downstream of a radiator. The oscillator generates radiation that is usedmore » as a seed for a high gain harmonic generation (HGHG) FEL which is upstream of the oscillator. For the first few pulses the oscillator builds up power and, until power is built up, the radiator has no HGHG seed. As power in the oscillator saturates, the HGHG is seeded and power is produced. The dynamics and stability of this radiator-first scheme is explored analytically and numerically. A single-pass map is derived using a semi-analytic model for FEL gain and saturation. Iteration of the map is shown to be in good agreement with simulations. A numerical example is presented for a soft X-ray FEL.« less
  • This study presents a novel method to improve the longitudinal coherence, efficiency and maximum photon energy of x-ray free electron lasers (XFELs). The method is equivalent to having two separate concatenated XFELs. The first uses one bunch of electrons to reach the saturation regime, generating a high power self-amplified spontaneous emission x-ray pulse at the fundamental and third harmonic. The x-ray pulse is filtered through an attenuator/monochromator and seeds a different electron bunch in the second FEL, using the fundamental and/or third harmonic as an input signal. In our method we combine the two XFELs operating with two bunches, separatedmore » by one or more rf cycles, in the same linear accelerator. We discuss the advantages and applications of the proposed system for present and future XFELs.« less
  • This study presents a novel method to improve the longitudinal coherence, efficiency and maximum photon energy of x-ray free electron lasers (XFELs). The method is equivalent to having two separate concatenated XFELs. The first uses one bunch of electrons to reach the saturation regime, generating a high power self-amplified spontaneous emission x-ray pulse at the fundamental and third harmonic. The x-ray pulse is filtered through an attenuator/monochromator and seeds a different electron bunch in the second FEL, using the fundamental and/or third harmonic as an input signal. In our method we combine the two XFELs operating with two bunches, separatedmore » by one or more rf cycles, in the same linear accelerator. We discuss the advantages and applications of the proposed system for present and future XFELs.« less
  • In a high-gain free-electron laser, strong bunching at the fundamental wavelength can drive substantial harmonic bunching and sizable power levels at the harmonic frequencies. In this paper, we investigate the three-dimensional evolution of the harmonic fields based on the coupled Maxwell-Vlasov equations that take into account the nonlinear harmonic interaction. Each harmonic field is the sum of a self-amplified term and a term driven by the nonlinear harmonic interaction. In the exponential gain regime, the growth rate of the dominant nonlinear term is much faster than that of the self-amplified harmonic field. As a result, the gain length and themore » transverse profile of the first few harmonics are completely determined by those of the fundamental. A percentage of the fundamental power level is found at the third harmonic frequency right before saturation for the current self-amplified spontaneous emission projects.« less