IPAC2015 - List of Authors (Zhao, Z.T.)

Paper	Title	Page
MOPJE008	Suppression of Microbunching Instability via a Transverse Gradient Undulator	300
	D. Huang, H.X. Deng, C. Feng, D. Gu, Q. Gu, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	Funding: the Major State Basic Research Development Program of China (2011CB808300) and the National Natural Science Foundation of China (11275253, 11475250 and 11322550). The microbunching instability in the linear accelerator (linac) of a free-electron laser facility has always been a problem that degrades the electron beam quality. In this paper, a quite simple and inexpensive technique is proposed to smooth the electron beam current profile to suppress the instability. By directly adding a short undulator with transverse gradient field right after the injector to couple the transverse spread into the longitudinal direction, additional density mixing in the electron beam is introduced to smooth the current profile, which results in the reduction of the gain of the microbunching instability. The magnitude of the density mixing can be easily controlled by turning the strength of the undulator magnet field. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in the accelerator of an X-Ray free-electron laser.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE008
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MOPJE009	Lattice Design of the SSRF-U Storage Ring	304
	S.Q. Tian, B.C. Jiang, M.Z. Zhang, Q.L. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	Multi-Bend Achromatic (MBA) cell has been well known to significantly reduce the beam emittance of the synchrotron radiation light sources in the past two decades. With the great development of the high gradient magnets, the small-aperture vacuum chamber and the precise alignment, the ultimate-emittance ring based on MBA lattice became practical in recent years. We present a preliminary lattice design for the upgraded SSRF storage ring based on a 7BA lattice in this paper. The circumference and the number of the straight sections are preserved for the existing tunnel. The beam energy is reduced to 3 GeV, and the beam emittance is reduced to about 200 pm.rad. The optimized dynamic aperture is about 10 mm in the horizontal plane, and a sufficient beam injection based on the closed orbit bump can be implemented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE009
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TUPJE019	Operating Cascaded High-gain Harmonic Generation with Double-pulse Electron Beams	1661
	Z. Wang, C. Feng, Q. Gu, Z.T. Zhao SINAP, Shanghai, People's Republic of China L. Yu BNL, Upton, Long Island, New York, USA
	Cascaded high gain harmonic generation (HGHG) is the primary candidate for the generation of high power, full temporal coherent radiation at the wavelength of nanometer. However, the experimental results at the existing facility show large fluctuation of the output energy pulse at the second stage of cascading. In this paper, we study the scheme of double-pulse electron beams, which is helpful to increase the stability of pulse energy against the timing jitter. The method to generate double-pulse electron beams is shown in the paper and comparison between double-pulse scheme and standard cascaded HGHG is present base on three-dimensional start-to-end simulation to give a straightforward image on the obviously improvement of the FEL stability.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE019
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TUPJE022	Study on Beam Dynamics of a Knot-APPLE Undulator Proposed for SSRF	1669
	Q.L. Zhang, B.C. Jiang, S.Q. Tian, Z.T. Zhao, Q.G. Zhou SINAP, Shanghai, People's Republic of China
	A new type of undulator, Knot-APPLE undulator, is proposed for SSRF as a solution to reduce the heat load of on-axis high harmonics without losing its capability of tuning synchrotron polarization. It will be applied for SSRF Photoemission Spectroscopy beamline (PES-beamline) in the near future. Impact of the undulator on the beam dynamics has been studied based on the 3D magnetic field model and kick map analysis. Linear optics can be retained by quadrupole compensation within two adjacent cells. Dynamical aperture (DA) shrinkage has been found in the tracking and optimized with sextupoles. An active correction scheme of current strips is studied to compensate the kick maps, and both the linear and nonlinear effects are suppressed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE022
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TUPJE023	Consideration on the Future Major Upgrades of the SSRF Storage Ring	1672
	Z.T. Zhao, B.C. Jiang, Y.B. Leng, S.Q. Tian, L. Yin, M.Z. Zhang SINAP, Shanghai, People's Republic of China
	The SSRF storage ring was in operation from 2008, currently it is operating at the energy of 3.5GeV, the natural emittance of 3.9 nm-rad and the beam current of 240 mA, serving for 13 beamlines with 9 IDs. There will be around 40 operated beamlines around 2020, which need some upgrade of the storage ring existing performance, such as the new lattice with superbends. And looking for the future beyond, the major upgrade towards a diffraction limited storage ring is under consideration. This paper presents the initial investigation and the proposal on the ultimate storage ring upgrade for SSRF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE023
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WEPMN026	Development of Non-resonant Perturbing Method for Tuning Traveling Wave Deflecting Structures	2985
	J.H. Tan, W. Fang, Q. Gu, Z.T. Zhao SINAP, Shanghai, People's Republic of China D.C. Tong TUB, Beijing, People's Republic of China
	For traveling wave accelerating structures, the tuning method assisted by bead pull technique based on non-resonant perturbation field distribution measurement has been widely used. Long periodic traveling wave deflecting structure, which operating at HEM11 mode, is difficult to use non-resonant perturbation method, and a improved method has been developed for measuring and tuning by "cage" type perturbing object at SINAP. The measurements on x-band traveling wave deflecting structure are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN026
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Paper

Title

Page

Suppression of Microbunching Instability via a Transverse Gradient Undulator

300

D. Huang, H.X. Deng, C. Feng, D. Gu, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Funding: the Major State Basic Research Development Program of China (2011CB808300) and the National Natural Science Foundation of China (11275253, 11475250 and 11322550).
The microbunching instability in the linear accelerator (linac) of a free-electron laser facility has always been a problem that degrades the electron beam quality. In this paper, a quite simple and inexpensive technique is proposed to smooth the electron beam current profile to suppress the instability. By directly adding a short undulator with transverse gradient field right after the injector to couple the transverse spread into the longitudinal direction, additional density mixing in the electron beam is introduced to smooth the current profile, which results in the reduction of the gain of the microbunching instability. The magnitude of the density mixing can be easily controlled by turning the strength of the undulator magnet field. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in the accelerator of an X-Ray free-electron laser.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE008

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

MOPJE009

Lattice Design of the SSRF-U Storage Ring

304

S.Q. Tian, B.C. Jiang, M.Z. Zhang, Q.L. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Multi-Bend Achromatic (MBA) cell has been well known to significantly reduce the beam emittance of the synchrotron radiation light sources in the past two decades. With the great development of the high gradient magnets, the small-aperture vacuum chamber and the precise alignment, the ultimate-emittance ring based on MBA lattice became practical in recent years. We present a preliminary lattice design for the upgraded SSRF storage ring based on a 7BA lattice in this paper. The circumference and the number of the straight sections are preserved for the existing tunnel. The beam energy is reduced to 3 GeV, and the beam emittance is reduced to about 200 pm.rad. The optimized dynamic aperture is about 10 mm in the horizontal plane, and a sufficient beam injection based on the closed orbit bump can be implemented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE009

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

TUPJE019

Operating Cascaded High-gain Harmonic Generation with Double-pulse Electron Beams

1661

Z. Wang, C. Feng, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
L. Yu
BNL, Upton, Long Island, New York, USA

Cascaded high gain harmonic generation (HGHG) is the primary candidate for the generation of high power, full temporal coherent radiation at the wavelength of nanometer. However, the experimental results at the existing facility show large fluctuation of the output energy pulse at the second stage of cascading. In this paper, we study the scheme of double-pulse electron beams, which is helpful to increase the stability of pulse energy against the timing jitter. The method to generate double-pulse electron beams is shown in the paper and comparison between double-pulse scheme and standard cascaded HGHG is present base on three-dimensional start-to-end simulation to give a straightforward image on the obviously improvement of the FEL stability.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE019

Export •

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

TUPJE022

Study on Beam Dynamics of a Knot-APPLE Undulator Proposed for SSRF

1669

Q.L. Zhang, B.C. Jiang, S.Q. Tian, Z.T. Zhao, Q.G. Zhou
SINAP, Shanghai, People's Republic of China

A new type of undulator, Knot-APPLE undulator, is proposed for SSRF as a solution to reduce the heat load of on-axis high harmonics without losing its capability of tuning synchrotron polarization. It will be applied for SSRF Photoemission Spectroscopy beamline (PES-beamline) in the near future. Impact of the undulator on the beam dynamics has been studied based on the 3D magnetic field model and kick map analysis. Linear optics can be retained by quadrupole compensation within two adjacent cells. Dynamical aperture (DA) shrinkage has been found in the tracking and optimized with sextupoles. An active correction scheme of current strips is studied to compensate the kick maps, and both the linear and nonlinear effects are suppressed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE022

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

TUPJE023

Consideration on the Future Major Upgrades of the SSRF Storage Ring

1672

Z.T. Zhao, B.C. Jiang, Y.B. Leng, S.Q. Tian, L. Yin, M.Z. Zhang
SINAP, Shanghai, People's Republic of China

The SSRF storage ring was in operation from 2008, currently it is operating at the energy of 3.5GeV, the natural emittance of 3.9 nm-rad and the beam current of 240 mA, serving for 13 beamlines with 9 IDs. There will be around 40 operated beamlines around 2020, which need some upgrade of the storage ring existing performance, such as the new lattice with superbends. And looking for the future beyond, the major upgrade towards a diffraction limited storage ring is under consideration. This paper presents the initial investigation and the proposal on the ultimate storage ring upgrade for SSRF.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE023

Export •

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

WEPMN026

Development of Non-resonant Perturbing Method for Tuning Traveling Wave Deflecting Structures

2985

J.H. Tan, W. Fang, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
D.C. Tong
TUB, Beijing, People's Republic of China

For traveling wave accelerating structures, the tuning method assisted by bead pull technique based on non-resonant perturbation field distribution measurement has been widely used. Long periodic traveling wave deflecting structure, which operating at HEM11 mode, is difficult to use non-resonant perturbation method, and a improved method has been developed for measuring and tuning by "cage" type perturbing object at SINAP. The measurements on x-band traveling wave deflecting structure are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN026

Export •

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