FEL2017 - List of Authors (Qin, W.)

Paper	Title	Page
MOP013	Hundred-Gigawatt X-Ray Self-Seeded High-Gain Harmonic Generation	53
	L. Zeng, S. Huang, K.X. Liu, W. Qin, G. Zhao PKU, Beijing, People's Republic of China Y. Ding, Z. Huang SLAC, Menlo Park, California, USA
	Self-seeded high-gain harmonic generation is a possible way to extend the wavelength of a soft x-ray free-electron laser (FEL). We have carried out simulation study on harmonic generation within the photon energy range from 2 keV to 4.5 keV, which is difficult to achieve due to a lack of monochromator materials. In this work, we demonstrate the third harmonic FEL with the fundamental wavelength at 1.52 nm. Our results shows that, by using undulator tapering technique, sub-terawatt narrow-bandwidth FEL output can be obtained.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP013
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MOP014	Harmonic Lasing Towards Shorter Wavelengths in Soft X-Ray Self-Seeding FELs	57
	L. Zeng, S. Huang, K.X. Liu, W. Qin, G. Zhao PKU, Beijing, People's Republic of China Y. Ding, Z. Huang SLAC, Menlo Park, California, USA
	In this paper, we study a simple harmonic lasing scheme to extend the wavelength of X-ray self-seeding FELs. The self-seeding amplifier is comprised of two stages. In the first stage, the fundamental radiation is amplified but well restricted below saturation, and simultaneously harmonic radiation is generated. In the second stage, the fundamental radiation is suppressed while the harmonic radiation is amplified to saturation. We performed a start-to-end simulation to demonstrate third harmonic lasing in a soft x-ray self-seeding FEL at the fundamental wavelength of 1.52 nm. Our simulations show that a stable narrow-band FEL at GW levels can be obtained.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP014
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TUC03	High-Flux, Fully Coherent X-Ray FEL Oscillator
	K.-J. Kim, S.P. Kearney, T. Kolodziej, R.R. Lindberg, X. Shi, D. Shu, Yu. Shvyd'ko ANL, Argonne, Illinois, USA K.L.F. Bane, Y. Ding, P. Emma, W.M. Fawley, J.B. Hastings, Z. Huang, J. Krzywinski, G. Marcus, T.J. Maxwell SLAC, Menlo Park, California, USA V.D. Blank, S. Terentiev TISNCM, Troitsk, Russia W.M. Fawley Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy C. Grizolli LNLS, Campinas, Brazil W. Qin PKU, Beijing, People's Republic of China S. Stoupin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J. Zemella DESY, Hamburg, Germany
	Funding: The ANL part of this work is supported by the U.S. DOE Office of Science under Contract No. DE-AC02-06CH11357 and the SLAC part under contract No. DE-AC02-76SF00515. By optimizing the parameters of the accelerator, undulator, and the optical cavity, an XFELO driven by an 8-GeV superconducting linac is predicted to produce 10^zEhNZeHn photons per pulse at the important photon energies around 14.4 keV.* This is an order of magnitude larger than that in previous designs. With a BW of 3 meV (FWHM), rep rate of 1 MHz, and taking into account the full coherence, the spectral brightness is then 2×10²⁶ photons per (mm2mr2 0.1\% BW), which is higher than any other source currently operating or anticipated in the future. Experiments at APS beam lines have shown that a high-quality diamond crystal can survive the power density (~15 kW/mm2) expected at the XFELO intra-cavity crystals preserving the high reflectivity.* The compound refractive lenses can serve as the focusing element. Adding an XFELO to the suite of other FEL sources will, at a minor incremental cost but with a major scientific payoff, significantly expand the scientific capabilities at superconducting linac-based XFEL facilities, such as the European XFEL, the proposed LCLS-II High Energy upgrade and the XFEL project in Shanghai. * W. Qin et al., this conference. R.R. Lindberg et al., Phys. Rev. ST Accel. Beams, vol 14, 403 (2011). * T. Kolodziej et al., this conference.
	Slides TUC03 [4.956 MB]
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WEA03	Simulation Optimization of DC-SRF Photoinjector for Low-Emittance Electron Beam Generation
	K.X. Liu, J.E. Chen, W. Cheng, L.W. Feng, J.K. Hao, S. Huang, L. Lin, W. Qin, S.W. Quan, F. Wang, H.M. Xie, F. Zhu PKU, Beijing, People's Republic of China
	A DC and superconducting rf (SRF) combined photoinjector, DC-SRF photoinjector, has been developed at Peking University to generate high repetition-rate electron bunches. At present stable operation of the DC-SRF photoinjector has been realized and the electron beam has been delivered to a SRF linac with two 9-cell TESLA-type cavities for further acceleration and experiments. Here we will present our latest progress on the DC-SRF photoinjector. We will also present our recent simulation work to decrease the emittance. The purpose is to build an upgraded DC-SRF photoinjector capable of driving CW X-ray free-electron lasers.
	Slides WEA03 [6.287 MB]
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MOP062	X-ray FEL Oscillator Seeded Harmonic Amplifier for High Energy Photons	196
	W. Qin, J. Wu SLAC, Menlo Park, California, USA K.-J. Kim, R.R. Lindberg ANL, Argonne, Illinois, USA
	High-power, high-energy X-ray pulses in the range of several tens of keV have important applications for material sciences.* The unique feature of an X-ray FEL Oscillator (XFELO) makes it possible to seed a harmonic amplifier to produce such high energy photons.** In this contribution, we present simulation studies using 14.4-keV output pulses from an XFELO to generate harmonics around 40 keV (3rd harmonic) and 60 keV (4th harmonic). Techniques such as undulator tapering and fresh bunch lasing are considered to improve the amplifier performance. * MaRIE project: http://www.lanl.gov/science-innovation/science-facilities/marie/. ** K.-J. Kim, XFELO-Seeded Amplifier, talk on MaRIE workshop, 2016.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP062
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TUC05	Start-to-End Simulations for an X-Ray FEL Oscillator at the LCLS-II and LCLS-II-HE	247
	W. Qin, K.L.F. Bane, Y. Ding, Z. Huang, G. Marcus, T.J. Maxwell SLAC, Menlo Park, California, USA S. Huang, K.X. Liu PKU, Beijing, People's Republic of China K.-J. Kim, R.R. Lindberg ANL, Argonne, Illinois, USA
	The proposed high repetition-rate electron beam from the LCLS-II and LCLS-II High Energy (LCLS-II-HE) upgrade are promising sources as drivers for an X-ray FEL Oscillator (XFELO) operating at both the harmonic and fundamental frequencies. In this contribution we present start-to-end simulations for an XFELO operating at the fifth harmonic with 4 GeV LCLS-II beam and at the fundamental with 8 GeV LCLS-II-HE beam. The electron beam longitudinal phase space is optimized by shaping the photoinjector laser and adjusting various machine parameters. The XFELO simulations show that high-flux output radiation pulses with 10¹⁰ photons and 3 meV (FWHM) spectral bandwidth can be obtained with the 8 GeV configuration.
	Slides TUC05 [3.802 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUC05
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TUP057	Measurement of Short-Wavelength High-Gain FEL Temporal Coherence Length by a Phase Shifter	344
	G. Zhou IHEP, Beijing, People's Republic of China W. Liu USTC/NSRL, Hefei, Anhui, People's Republic of China W. Qin, T.O. Raubenheimer, J. Wu, C. Yang SLAC, Menlo Park, California, USA C.-Y. Tsai Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA B. Yang University of Texas at Arlington, Arlington, USA M. Yoon POSTECH, Pohang, Kyungbuk, Republic of Korea
	Funding: The work was supported by the US Department of Energy (DOE) under contract DE-AC02-76SF00515 and the US DOE Office of Science Early Career Research Program grant FWP-2013-SLAC-100164. Short-wavelength high-gain free-electron lasers (FELs) are now well established as a source of ultra-fast, ultra-brightness, longitudinally partial coherent light. Since coherence is one of the fundamental properties of light source, so continual effort is devoted to high-gain free-electron laser coherence measurements. In this work, we propose a possible approach, employing a phase shifter to induce electron beam delay to measure the temporal coherence length. Simple analysis, numerical simulation and preliminary experimental results are presented. This approach can be robust and independent of frequency.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUP057
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Hundred-Gigawatt X-Ray Self-Seeded High-Gain Harmonic Generation

53

L. Zeng, S. Huang, K.X. Liu, W. Qin, G. Zhao
PKU, Beijing, People's Republic of China
Y. Ding, Z. Huang
SLAC, Menlo Park, California, USA

Self-seeded high-gain harmonic generation is a possible way to extend the wavelength of a soft x-ray free-electron laser (FEL). We have carried out simulation study on harmonic generation within the photon energy range from 2 keV to 4.5 keV, which is difficult to achieve due to a lack of monochromator materials. In this work, we demonstrate the third harmonic FEL with the fundamental wavelength at 1.52 nm. Our results shows that, by using undulator tapering technique, sub-terawatt narrow-bandwidth FEL output can be obtained.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP014

Harmonic Lasing Towards Shorter Wavelengths in Soft X-Ray Self-Seeding FELs

57

L. Zeng, S. Huang, K.X. Liu, W. Qin, G. Zhao
PKU, Beijing, People's Republic of China
Y. Ding, Z. Huang
SLAC, Menlo Park, California, USA

In this paper, we study a simple harmonic lasing scheme to extend the wavelength of X-ray self-seeding FELs. The self-seeding amplifier is comprised of two stages. In the first stage, the fundamental radiation is amplified but well restricted below saturation, and simultaneously harmonic radiation is generated. In the second stage, the fundamental radiation is suppressed while the harmonic radiation is amplified to saturation. We performed a start-to-end simulation to demonstrate third harmonic lasing in a soft x-ray self-seeding FEL at the fundamental wavelength of 1.52 nm. Our simulations show that a stable narrow-band FEL at GW levels can be obtained.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP014

Export •

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TUC03

High-Flux, Fully Coherent X-Ray FEL Oscillator

K.-J. Kim, S.P. Kearney, T. Kolodziej, R.R. Lindberg, X. Shi, D. Shu, Yu. Shvyd'ko
ANL, Argonne, Illinois, USA
K.L.F. Bane, Y. Ding, P. Emma, W.M. Fawley, J.B. Hastings, Z. Huang, J. Krzywinski, G. Marcus, T.J. Maxwell
SLAC, Menlo Park, California, USA
V.D. Blank, S. Terentiev
TISNCM, Troitsk, Russia
W.M. Fawley
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
C. Grizolli
LNLS, Campinas, Brazil
W. Qin
PKU, Beijing, People's Republic of China
S. Stoupin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J. Zemella
DESY, Hamburg, Germany

Funding: The ANL part of this work is supported by the U.S. DOE Office of Science under Contract No. DE-AC02-06CH11357 and the SLAC part under contract No. DE-AC02-76SF00515.
By optimizing the parameters of the accelerator, undulator, and the optical cavity, an XFELO driven by an 8-GeV superconducting linac is predicted to produce 10^zEhNZeHn photons per pulse at the important photon energies around 14.4 keV.* This is an order of magnitude larger than that in previous designs.** With a BW of 3 meV (FWHM), rep rate of 1 MHz, and taking into account the full coherence, the spectral brightness is then 2×10²⁶ photons per (mm2mr2 0.1\% BW), which is higher than any other source currently operating or anticipated in the future. Experiments at APS beam lines have shown that a high-quality diamond crystal can survive the power density (~15 kW/mm2) expected at the XFELO intra-cavity crystals preserving the high reflectivity.*** The compound refractive lenses can serve as the focusing element. Adding an XFELO to the suite of other FEL sources will, at a minor incremental cost but with a major scientific payoff, significantly expand the scientific capabilities at superconducting linac-based XFEL facilities, such as the European XFEL, the proposed LCLS-II High Energy upgrade and the XFEL project in Shanghai.
* W. Qin et al., this conference.
** R.R. Lindberg et al., Phys. Rev. ST Accel. Beams, vol 14, 403 (2011).
*** T. Kolodziej et al., this conference.

Slides TUC03 [4.956 MB]

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WEA03

Simulation Optimization of DC-SRF Photoinjector for Low-Emittance Electron Beam Generation

K.X. Liu, J.E. Chen, W. Cheng, L.W. Feng, J.K. Hao, S. Huang, L. Lin, W. Qin, S.W. Quan, F. Wang, H.M. Xie, F. Zhu
PKU, Beijing, People's Republic of China

A DC and superconducting rf (SRF) combined photoinjector, DC-SRF photoinjector, has been developed at Peking University to generate high repetition-rate electron bunches. At present stable operation of the DC-SRF photoinjector has been realized and the electron beam has been delivered to a SRF linac with two 9-cell TESLA-type cavities for further acceleration and experiments. Here we will present our latest progress on the DC-SRF photoinjector. We will also present our recent simulation work to decrease the emittance. The purpose is to build an upgraded DC-SRF photoinjector capable of driving CW X-ray free-electron lasers.

Slides WEA03 [6.287 MB]

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP062

X-ray FEL Oscillator Seeded Harmonic Amplifier for High Energy Photons

196

W. Qin, J. Wu
SLAC, Menlo Park, California, USA
K.-J. Kim, R.R. Lindberg
ANL, Argonne, Illinois, USA

High-power, high-energy X-ray pulses in the range of several tens of keV have important applications for material sciences.* The unique feature of an X-ray FEL Oscillator (XFELO) makes it possible to seed a harmonic amplifier to produce such high energy photons.** In this contribution, we present simulation studies using 14.4-keV output pulses from an XFELO to generate harmonics around 40 keV (3rd harmonic) and 60 keV (4th harmonic). Techniques such as undulator tapering and fresh bunch lasing are considered to improve the amplifier performance.
* MaRIE project: http://www.lanl.gov/science-innovation/science-facilities/marie/.
** K.-J. Kim, XFELO-Seeded Amplifier, talk on MaRIE workshop, 2016.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP062

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC05

Start-to-End Simulations for an X-Ray FEL Oscillator at the LCLS-II and LCLS-II-HE

247

W. Qin, K.L.F. Bane, Y. Ding, Z. Huang, G. Marcus, T.J. Maxwell
SLAC, Menlo Park, California, USA
S. Huang, K.X. Liu
PKU, Beijing, People's Republic of China
K.-J. Kim, R.R. Lindberg
ANL, Argonne, Illinois, USA

The proposed high repetition-rate electron beam from the LCLS-II and LCLS-II High Energy (LCLS-II-HE) upgrade are promising sources as drivers for an X-ray FEL Oscillator (XFELO) operating at both the harmonic and fundamental frequencies. In this contribution we present start-to-end simulations for an XFELO operating at the fifth harmonic with 4 GeV LCLS-II beam and at the fundamental with 8 GeV LCLS-II-HE beam. The electron beam longitudinal phase space is optimized by shaping the photoinjector laser and adjusting various machine parameters. The XFELO simulations show that high-flux output radiation pulses with 10¹⁰ photons and 3 meV (FWHM) spectral bandwidth can be obtained with the 8 GeV configuration.

Slides TUC05 [3.802 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUC05

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP057

Measurement of Short-Wavelength High-Gain FEL Temporal Coherence Length by a Phase Shifter

344

G. Zhou
IHEP, Beijing, People's Republic of China
W. Liu
USTC/NSRL, Hefei, Anhui, People's Republic of China
W. Qin, T.O. Raubenheimer, J. Wu, C. Yang
SLAC, Menlo Park, California, USA
C.-Y. Tsai
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
B. Yang
University of Texas at Arlington, Arlington, USA
M. Yoon
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: The work was supported by the US Department of Energy (DOE) under contract DE-AC02-76SF00515 and the US DOE Office of Science Early Career Research Program grant FWP-2013-SLAC-100164.
Short-wavelength high-gain free-electron lasers (FELs) are now well established as a source of ultra-fast, ultra-brightness, longitudinally partial coherent light. Since coherence is one of the fundamental properties of light source, so continual effort is devoted to high-gain free-electron laser coherence measurements. In this work, we propose a possible approach, employing a phase shifter to induce electron beam delay to measure the temporal coherence length. Simple analysis, numerical simulation and preliminary experimental results are presented. This approach can be robust and independent of frequency.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUP057

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)