IPAC2018 - List of Authors (Wang, D.)

Paper	Title	Page
THPMK068	High degree circular polarization at x-ray self-seeding FELs with crossed-planar undulators	4453
	K. Li, H.X. Deng, Z.F. Gao, B. Liu, D. Wang SINAP, Shanghai, People's Republic of China
	Funding: Work was supported by the National Natural Science Foundation of China (11775293), the National Key Research and Development Program of China (2016YFA0401900). The crossed undulator configuration for a high-gain free-electron laser (FEL) is well-known for the ability of versatile polarization control. However, the degree of polarization is very sensitive to power and phase between the two stages of crossed undulators. In this poster, we introduce the generation of high degree circular polarization hard x-ray FEL with crossed-planar undulator seeded by self-seeding. The reverse taper and taper undulator technology are employed for improving its performance. With the combination of high degree (>95%) circular polarization and flexibility of polarization switching, this scheme might be useful for some scientific research in the future.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK068
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THPMK069	Design of the Beam Switchyard of a Soft X-ray FEL User Facility in Shanghai	4456
	S. Chen, H.X. Deng, C. Feng, B. Liu, D. Wang, R. Wang SINAP, Shanghai, People's Republic of China
	A soft X-ray FEL user facility, which is based on the existing test facility located in the Zhangjiang Campus of SINAP, is under construction. Two undulator lines will be installed parallelly in the undulator hall and their electron beams are served by a 1.5 GeV linac. For simultaneous operation of the two undulator lines, a beam distribution system should be used to connect the linac and the undulator lines. In this paper, the physics design of this beam distribution system will be presented and also the beam dynamic issues will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK069
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THPMK070	Optimization for the Two-Stage Hard X-Ray Self-Seeding Scheme the SCLF	4460
	T. Liu, C. Feng, D. Wang, X. Wang, K.Q. Zhang SINAP, Shanghai, People's Republic of China
	Funding: Work supported by the National Natural Science Foundation of China 11475250 and 11605277, National Key Research and Development 2016YFA0401901 and Youth Innovation Promotion Association CAS 2015209. Self-seeding mode has been demonstrated a great advantage for the achievement of a high brightness X-ray with a pure spectrum. Single-bunch self-seeding scheme with wake monochromators is adopted for the realization of the hard X-ray FEL at the Shanghai Coherent Light Facility (SCLF). Limited by the heat-loading of the monochromator, the two or multiple stages self-seeding scheme is required. In this contribution, we present a basic two-stage scheme design and optimization for the generation of the photon energy range of 3 keV to 15 keV at the line FEL-I of the SCLF. Simulation results show the peak power and pulse energy each stage, which illustrates the loaded energy required of the crystal monochromator as a pointcut of its following thermal analysis. The electron beam energy used in the study is 8 GeV and the central photon energy is 12.4 keV.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK070
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THPMK073	Multi FEL Lines with Compact Undulator Layout	4470
	D. Wang SINAP, Shanghai, People's Republic of China
	Today the high repetition rate X-ray Free Electron Lasers based on superconducting radiofrequency technologies have come to their age. Such kind of facilities are able to serve many FEL photon beamlines simultaneously with each of which have large flexibilities in selecting wavelength, intensity, polarization, coherence and other properties through independent tuning of the undulator magnets. In reality the space needed to accommodate many undulator lines could be a limiting factor of user capacity, especially for the high rep rate XFELs that tend to utilize the underground tunnel to host long superconducting accelerator machines. In this paper we present a concept of compact undulator layout for more FEL lines in the precious tunnel spaces or similar environment. Shanghai Coherent Light Facility(SCLF) is a high repe-tition rate X-ray Free Electron Lasers installed in under-ground tunnels with an overall length of more than 3 km. The concept described in this paper could be applied to the SCLF or similar FEL facilities. The design and R&D progress will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK073
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THPMK077	The Preliminary Experiment Studies for Soft X-Ray Self-Seeding System Design of SCLF Facility	4481
	K.Q. Zhang, C. Feng, D. Wang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	The preliminary experiment studies for soft x-ray self-seeding system design of SCLF facility have been pre-sented in this paper. Some practical problems and pre-engineering design have been studied for the experimental prepare of soft x-ray self-seeding for the future SCLF facility. The monochromator system designs in this paper include optical structure, optical parameters and mechanical design. The designed optical system has an optical resolution of 1/10000 at the photon energy of 700-1300eV based on the optical simulation. To make the system satisfy the experimental requirements, mechanical install requirements and install precisions are also analysed. Considering the actual varies errors, the errors analyses such as the surface errors of the optical mirror and the machining errors of the VLS grating are also carried out. In conclusion, preliminary experimental studies including system design and varies engineering requirements are introduced to make sure that the presented design is reliable for final soft x-ray self-seeding experiment of SCLF facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK077
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Paper

Title

Page

High degree circular polarization at x-ray self-seeding FELs with crossed-planar undulators

4453

K. Li, H.X. Deng, Z.F. Gao, B. Liu, D. Wang
SINAP, Shanghai, People's Republic of China

Funding: Work was supported by the National Natural Science Foundation of China (11775293), the National Key Research and Development Program of China (2016YFA0401900).
The crossed undulator configuration for a high-gain free-electron laser (FEL) is well-known for the ability of versatile polarization control. However, the degree of polarization is very sensitive to power and phase between the two stages of crossed undulators. In this poster, we introduce the generation of high degree circular polarization hard x-ray FEL with crossed-planar undulator seeded by self-seeding. The reverse taper and taper undulator technology are employed for improving its performance. With the combination of high degree (>95%) circular polarization and flexibility of polarization switching, this scheme might be useful for some scientific research in the future.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK068

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

THPMK069

Design of the Beam Switchyard of a Soft X-ray FEL User Facility in Shanghai

4456

S. Chen, H.X. Deng, C. Feng, B. Liu, D. Wang, R. Wang
SINAP, Shanghai, People's Republic of China

A soft X-ray FEL user facility, which is based on the existing test facility located in the Zhangjiang Campus of SINAP, is under construction. Two undulator lines will be installed parallelly in the undulator hall and their electron beams are served by a 1.5 GeV linac. For simultaneous operation of the two undulator lines, a beam distribution system should be used to connect the linac and the undulator lines. In this paper, the physics design of this beam distribution system will be presented and also the beam dynamic issues will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK069

Export •

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

THPMK070

Optimization for the Two-Stage Hard X-Ray Self-Seeding Scheme the SCLF

4460

T. Liu, C. Feng, D. Wang, X. Wang, K.Q. Zhang
SINAP, Shanghai, People's Republic of China

Funding: Work supported by the National Natural Science Foundation of China 11475250 and 11605277, National Key Research and Development 2016YFA0401901 and Youth Innovation Promotion Association CAS 2015209.
Self-seeding mode has been demonstrated a great advantage for the achievement of a high brightness X-ray with a pure spectrum. Single-bunch self-seeding scheme with wake monochromators is adopted for the realization of the hard X-ray FEL at the Shanghai Coherent Light Facility (SCLF). Limited by the heat-loading of the monochromator, the two or multiple stages self-seeding scheme is required. In this contribution, we present a basic two-stage scheme design and optimization for the generation of the photon energy range of 3 keV to 15 keV at the line FEL-I of the SCLF. Simulation results show the peak power and pulse energy each stage, which illustrates the loaded energy required of the crystal monochromator as a pointcut of its following thermal analysis. The electron beam energy used in the study is 8 GeV and the central photon energy is 12.4 keV.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK070

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

THPMK073

Multi FEL Lines with Compact Undulator Layout

4470

D. Wang
SINAP, Shanghai, People's Republic of China

Today the high repetition rate X-ray Free Electron Lasers based on superconducting radiofrequency technologies have come to their age. Such kind of facilities are able to serve many FEL photon beamlines simultaneously with each of which have large flexibilities in selecting wavelength, intensity, polarization, coherence and other properties through independent tuning of the undulator magnets. In reality the space needed to accommodate many undulator lines could be a limiting factor of user capacity, especially for the high rep rate XFELs that tend to utilize the underground tunnel to host long superconducting accelerator machines. In this paper we present a concept of compact undulator layout for more FEL lines in the precious tunnel spaces or similar environment. Shanghai Coherent Light Facility(SCLF) is a high repe-tition rate X-ray Free Electron Lasers installed in under-ground tunnels with an overall length of more than 3 km. The concept described in this paper could be applied to the SCLF or similar FEL facilities. The design and R&D progress will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK073

Export •

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

THPMK077

The Preliminary Experiment Studies for Soft X-Ray Self-Seeding System Design of SCLF Facility

4481

K.Q. Zhang, C. Feng, D. Wang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

The preliminary experiment studies for soft x-ray self-seeding system design of SCLF facility have been pre-sented in this paper. Some practical problems and pre-engineering design have been studied for the experimental prepare of soft x-ray self-seeding for the future SCLF facility. The monochromator system designs in this paper include optical structure, optical parameters and mechanical design. The designed optical system has an optical resolution of 1/10000 at the photon energy of 700-1300eV based on the optical simulation. To make the system satisfy the experimental requirements, mechanical install requirements and install precisions are also analysed. Considering the actual varies errors, the errors analyses such as the surface errors of the optical mirror and the machining errors of the VLS grating are also carried out. In conclusion, preliminary experimental studies including system design and varies engineering requirements are introduced to make sure that the presented design is reliable for final soft x-ray self-seeding experiment of SCLF facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK077

Export •

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