IPAC2019 - List of Authors (Li, J.J.)

Paper	Title	Page
MOPGW054	Study on Spherical Aberration Correction of Solenoid Lens in Ultrafast Electron Diffraction	213
	Y.T. Yang, K. Fan, J.J. Li HUST, Wuhan, People’s Republic of China Y. Song Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China
	High electron beam quality is required in Ultrafast Electron Diffraction (UED) to achieve high spatial resolution. However, aberrations mainly induced by solenoid lens will deteriorate the beam quality and limit the resolution. Spherical aberration introduces the largest distortion which is unavoidable in the case of static cylindrically symmetric electromagnetic fields on the basis of Scherzer’s theorem. In order to reduce the spherical aberrations, different models have been designed which are composed of three symmetrical lens and one asymmetrical lens. We obtain the magnetic field distribution and calculate the aberration of each model by OPERA, and the result is that the solenoid without poles has the minimum aberration and meets the design requirement best.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW054
About •	paper received ※ 13 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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TUPTS052	Conceptual Design of a High-Performance Injector Based on Rf-Gated Gridded Thermionic Gun for Thz Fel	2046
	P. Yang, H.M. Chen, T. Hu, J.J. Li, Y. Lu HUST, Wuhan, People’s Republic of China G.Y. Feng, S.C. Zhang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Free-Electron Laser (FEL) has higher requirements on electron beam properties, for example, low transverse emittance, small energy spread, short bunch length and high peak current. Taking compactness and economy into account, we aim to design a high-performance linear accelerator based on a RF-gated gridded thermionic electron gun, which will be used as the injector of the oscillator-type THz FEL facility at Huazhong University of Science and Technology of China. The RF-gated grid will be modulated with the fundamental and 3rd harmonic microwave of the LINAC frequency, which will be very helpful to get high electron capture efficiency and short bunch length. Concerning velocity bunching effect in the LINAC, electron bunch with good symmetry of current profile and bunch length less than 10 ps can be obtained at the exit of the injector. In this paper, design and beam dynamics simulation for the high-performance injector are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS052
About •	paper received ※ 26 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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THPGW043	Conceptual design of a MeV Ultrafast Electron Diffraction Based on 1.4 Cell RF Gun	3679
SUSPFO061	use link to see paper's listing under its alternate paper code
	J.J. Li, H.M. Chen, K. Fan, Y. Song, P. Yang, Y.T. Yang HUST, Wuhan, People’s Republic of China
	Ultrafast Electron Diffraction (UED) is a powerful tool to investigate the dynamic structure with temporal scale of 100 femtoseconds and spatial scale of atomic length. To achieve high quality diffraction patterns, the transverse emittance and the longitudinal length of electron bunches should be reduced. MeV UED, using photocath-ode RF gun instead of traditional DC gun, is being developed to produce high quality electron bunches with lower emittance and shorter length. We are developing a MeV UED facility based on a 1.4 cell photocathode RF gun that can provide higher acceleration gradient at Huazhong University of Science and Technology. In this paper, the conceptual design of the MeV UED is pro-posed with typical parameters of the system, as well as the ASTRA simulation results of optimization.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW043
About •	paper received ※ 11 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)

Paper

Title

Page

Study on Spherical Aberration Correction of Solenoid Lens in Ultrafast Electron Diffraction

213

Y.T. Yang, K. Fan, J.J. Li
HUST, Wuhan, People’s Republic of China
Y. Song
Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China

High electron beam quality is required in Ultrafast Electron Diffraction (UED) to achieve high spatial resolution. However, aberrations mainly induced by solenoid lens will deteriorate the beam quality and limit the resolution. Spherical aberration introduces the largest distortion which is unavoidable in the case of static cylindrically symmetric electromagnetic fields on the basis of Scherzer’s theorem. In order to reduce the spherical aberrations, different models have been designed which are composed of three symmetrical lens and one asymmetrical lens. We obtain the magnetic field distribution and calculate the aberration of each model by OPERA, and the result is that the solenoid without poles has the minimum aberration and meets the design requirement best.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW054

About •

paper received ※ 13 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

Export •

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

TUPTS052

Conceptual Design of a High-Performance Injector Based on Rf-Gated Gridded Thermionic Gun for Thz Fel

2046

P. Yang, H.M. Chen, T. Hu, J.J. Li, Y. Lu
HUST, Wuhan, People’s Republic of China
G.Y. Feng, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Free-Electron Laser (FEL) has higher requirements on electron beam properties, for example, low transverse emittance, small energy spread, short bunch length and high peak current. Taking compactness and economy into account, we aim to design a high-performance linear accelerator based on a RF-gated gridded thermionic electron gun, which will be used as the injector of the oscillator-type THz FEL facility at Huazhong University of Science and Technology of China. The RF-gated grid will be modulated with the fundamental and 3rd harmonic microwave of the LINAC frequency, which will be very helpful to get high electron capture efficiency and short bunch length. Concerning velocity bunching effect in the LINAC, electron bunch with good symmetry of current profile and bunch length less than 10 ps can be obtained at the exit of the injector. In this paper, design and beam dynamics simulation for the high-performance injector are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS052

About •

paper received ※ 26 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

Export •

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

THPGW043

Conceptual design of a MeV Ultrafast Electron Diffraction Based on 1.4 Cell RF Gun

3679

SUSPFO061

use link to see paper's listing under its alternate paper code

J.J. Li, H.M. Chen, K. Fan, Y. Song, P. Yang, Y.T. Yang
HUST, Wuhan, People’s Republic of China

Ultrafast Electron Diffraction (UED) is a powerful tool to investigate the dynamic structure with temporal scale of 100 femtoseconds and spatial scale of atomic length. To achieve high quality diffraction patterns, the transverse emittance and the longitudinal length of electron bunches should be reduced. MeV UED, using photocath-ode RF gun instead of traditional DC gun, is being developed to produce high quality electron bunches with lower emittance and shorter length. We are developing a MeV UED facility based on a 1.4 cell photocathode RF gun that can provide higher acceleration gradient at Huazhong University of Science and Technology. In this paper, the conceptual design of the MeV UED is pro-posed with typical parameters of the system, as well as the ASTRA simulation results of optimization.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW043

About •

paper received ※ 11 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)