IPAC2019 - List of Authors (Feng, C.)

Paper	Title	Page
TUPRB047	Proposal of the Reflection Hard X-Ray Self-Seeding at the SHINE Project	1792
	T. Liu, C. Feng SARI-CAS, Pudong, Shanghai, People’s Republic of China
	FEL self-seeding has been demonstrated a great advantage for the generation of a fully coherent and high brightness X-ray pulse experimentally. Generally, transmission monochromators with single crystal are adopted worldwide, such as LCLS, PAL-XFEL and European-XFEL. Recently, the self-seeding scheme based on a reflection monochromator with a double-crystal is proposed and demonstrated at SACLA successfully. In view of several potential advantages of the reflection type, here we give the proposal of the reflection monochromator based self-seeding and enable the application on the SHINE project. This manuscript is mainly focus on monochromator schemes at SHINE, instead of FEL simulations. We will present considerable schemes based on the specific undulator line.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB047
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEXXPLM2	Slippage Boosted Spectral Cleaning in a Seeded Free-Electron Laser
	C. Feng SARI-CAS, Pudong, Shanghai, People’s Republic of China
	The realization of fully coherent X-ray radiation pulse has been a long-standing challenge for free-electron lasers. A promising way for producing stable transform-limited pulses is based on the harmonic up-conversion techniques with a conventional laser as the seed. However, it is found that the insignificant phase error in the seed laser will be eventually multiplied by the harmonic number, leading to a degradation of the output temporal coherence at short wavelength. Here, we report the demonstration of a slippage boosted spectral cleaning technique to mitigate the impact of seed laser induced phase errors and to improve the temporal coherence of a seeded FEL. Experimental results show that fully coherent radiation pulses can be generated in a seeded FEL with the help of the proposed technique.
	Slides WEXXPLM2 [4.915 MB]
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TUPGW045	Lattice Design for the Reversible SSMB	1507
	C.L. Li SINAP, Shanghai, People’s Republic of China A. Chao SLAC, Menlo Park, California, USA C. Feng, B.C. Jiang Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China
	Steady State Microbunching (SSMB) aiming at producing high average power radiation in the electron storage ring has been proposed by Ratner and Chao years ago. Reversible seeding scheme is one of the promising scenarios with less challenges on the storage ring lattice design. The key problem for reversible SSMB is the precise cancelation of the laser modulation which will allow producing turn-by-turn coherent radiation without spoiling the transverse emittances and energy spread. In this paper the lattice design for the microbunching generation and its cancelation will be presented. Also a storage ring lattice design will be shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW045
About •	paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPRB054	The Beam-Based Alignment Simulation and Preliminary Experiment at SXFEL	1804
	L. Zeng, H.X. Deng, C. Feng, D. Gu, B. Liu, Z.T. Zhao SINAP, Shanghai, People’s Republic of China G.L. Wang DICP, Dalian, People’s Republic of China
	The Shanghai soft X-ray Free-electron Laser facility (SXFEL) is now serving as an experimental platform for fundamental free-electron laser (FEL) principle tests. The machine puts very tight tolerance on the straightness of the electron beam orbit. It is hard to achieve the required trajectory due to the off-axis field of the misaligned quadrupoles and undulator segments especially for the SXFEL driven by low energy linac (840MeV). This tight requirement on electron beam straightness can only be met through the beam-based alignment (BBA) technology which achieved great success at LCLS, PAL-XFEL, European-XFEL and SCALA with high electron beam energies. But there has been no report about satisfactory BBA experiment results on soft X-ray FEL facility driven by relatively low energy linacs (on the order of 2 GeV or less) up to now. Here, we report the simulation results and preparatory experiment progress of the BBA at SXFEL with the method of dispersion-free steering (DFS). The experiment results show some improvements of the electron beam orbit and the phenomenon of the dispersion-free. The entire BBA experiment and a feedback system of electron beam trajectory may also be included.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB054
About •	paper received ※ 18 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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Paper

Title

Page

Proposal of the Reflection Hard X-Ray Self-Seeding at the SHINE Project

1792

T. Liu, C. Feng
SARI-CAS, Pudong, Shanghai, People’s Republic of China

FEL self-seeding has been demonstrated a great advantage for the generation of a fully coherent and high brightness X-ray pulse experimentally. Generally, transmission monochromators with single crystal are adopted worldwide, such as LCLS, PAL-XFEL and European-XFEL. Recently, the self-seeding scheme based on a reflection monochromator with a double-crystal is proposed and demonstrated at SACLA successfully. In view of several potential advantages of the reflection type, here we give the proposal of the reflection monochromator based self-seeding and enable the application on the SHINE project. This manuscript is mainly focus on monochromator schemes at SHINE, instead of FEL simulations. We will present considerable schemes based on the specific undulator line.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB047

About •

paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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

WEXXPLM2

Slippage Boosted Spectral Cleaning in a Seeded Free-Electron Laser

C. Feng
SARI-CAS, Pudong, Shanghai, People’s Republic of China

The realization of fully coherent X-ray radiation pulse has been a long-standing challenge for free-electron lasers. A promising way for producing stable transform-limited pulses is based on the harmonic up-conversion techniques with a conventional laser as the seed. However, it is found that the insignificant phase error in the seed laser will be eventually multiplied by the harmonic number, leading to a degradation of the output temporal coherence at short wavelength. Here, we report the demonstration of a slippage boosted spectral cleaning technique to mitigate the impact of seed laser induced phase errors and to improve the temporal coherence of a seeded FEL. Experimental results show that fully coherent radiation pulses can be generated in a seeded FEL with the help of the proposed technique.

Slides WEXXPLM2 [4.915 MB]

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

TUPGW045

Lattice Design for the Reversible SSMB

1507

C.L. Li
SINAP, Shanghai, People’s Republic of China
A. Chao
SLAC, Menlo Park, California, USA
C. Feng, B.C. Jiang
Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China

Steady State Microbunching (SSMB) aiming at producing high average power radiation in the electron storage ring has been proposed by Ratner and Chao years ago. Reversible seeding scheme is one of the promising scenarios with less challenges on the storage ring lattice design. The key problem for reversible SSMB is the precise cancelation of the laser modulation which will allow producing turn-by-turn coherent radiation without spoiling the transverse emittances and energy spread. In this paper the lattice design for the microbunching generation and its cancelation will be presented. Also a storage ring lattice design will be shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW045

About •

paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

Export •

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

TUPRB054

The Beam-Based Alignment Simulation and Preliminary Experiment at SXFEL

1804

L. Zeng, H.X. Deng, C. Feng, D. Gu, B. Liu, Z.T. Zhao
SINAP, Shanghai, People’s Republic of China
G.L. Wang
DICP, Dalian, People’s Republic of China

The Shanghai soft X-ray Free-electron Laser facility (SXFEL) is now serving as an experimental platform for fundamental free-electron laser (FEL) principle tests. The machine puts very tight tolerance on the straightness of the electron beam orbit. It is hard to achieve the required trajectory due to the off-axis field of the misaligned quadrupoles and undulator segments especially for the SXFEL driven by low energy linac (840MeV). This tight requirement on electron beam straightness can only be met through the beam-based alignment (BBA) technology which achieved great success at LCLS, PAL-XFEL, European-XFEL and SCALA with high electron beam energies. But there has been no report about satisfactory BBA experiment results on soft X-ray FEL facility driven by relatively low energy linacs (on the order of 2 GeV or less) up to now. Here, we report the simulation results and preparatory experiment progress of the BBA at SXFEL with the method of dispersion-free steering (DFS). The experiment results show some improvements of the electron beam orbit and the phenomenon of the dispersion-free. The entire BBA experiment and a feedback system of electron beam trajectory may also be included.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB054

About •

paper received ※ 18 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

Export •

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