IPAC2019 - List of Authors (Wan, W.)

Paper	Title	Page
WEPGW111	Design of Booster-to-Accumulator Transfer Line for Advanced Light Source Upgrade	2756
	C. Sun, Ph. Amstutz, T. Hellert, J.-Y. Jung, S.C. Leemann, J.R. Osborn, M. Placidi, C. Steier, C.A. Swenson, M. Venturini, W. Wan LBNL, Berkeley, California, USA
	Funding: Work supported by the Director Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. For the Advanced Light Source Upgrade, an on-axis swap-out injection is applied to exchange bunch trains between the storage ring and the accumulator ring. To replenish the accumulator ring before the swap-out injection, an electron beam from Linac is first injected into the ALS booster to ramp up the energy, and then transported to the accumulator through the Booster-to-Accumulator (BTA) transfer line. The design of the BTA transfer line is a challenging task as it has to fit within a tight space while accommodating the booster and accumulator rings at different elevations. Moreover, the BTA design needs to meet the optics boundary conditions and ideally minimize the size requirements of vacuum-chamber apertures. In this paper, we will present a design option of the BTA transfer line, which meets both space limitations and beam physics requirements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW111
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUPTS014	SINGLE SHOT CATHODE TRANSVERSE MOMENTUM IMAGING IN PHOTOINJECTORS	1964
SUSPFO016	use link to see paper's listing under its alternate paper code
	P.W. Huang, Y. Chen, J.D. Good, M. Groß, I.I. Isaev, C. Koschitzki, M. Krasilnikov, S. Lal, X. Li, O. Lishilin, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, H. Shaker, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany D. Filippetto, F. Sannibale LBNL, Berkeley, California, USA C.-X. Tang TUB, Beijing, People’s Republic of China W. Wan ShanghaiTech University, Shanghai, People’s Republic of China
	In state of the art photoinjector electron sources, cathode performance determines the lower limit of achievable beam emittance. Measuring the thermal emittance at the photocathodes in electron guns is of vital importance for improving the injectors. Traditional methods, like solenoid scan, pepper-pot, need multi-shots and are time-consuming, therefore suffer from machine stability. Here we propose a new method, named cathode transverse momentum imaging. By tuning the gun solenoid focusing, the electrons’ transverse momentum at the cathode is imaged to a downstream screen, which enables a single shot measurement. Several experiments have been done at the Photo Injector Test Facility at DESY in Zeuthen (PITZ) with a Cs2Te cathode. Measurements of cathode transverse momentum, the corresponding spectra, cathode transverse momentum map and its correlation with surface electric field are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS014
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPMP053	Tuning Quadrupoles for Brighter and Sharper Ultra-fast Electron Diffraction Imaging	3571
	X. Yang, L. Doom, M.G. Fedurin, Y. Hidaka, J.J. Li, D. Padrazo Jr, T.V. Shaftan, V.V. Smaluk, G.M. Wang, L.-H. Yu, Y. Zhu BNL, Upton, Long Island, New York, USA W. Wan ShanghaiTech University, Shanghai, People’s Republic of China
	Funding: BNL LDRD We report our proof-of-principle design and experi-mental commissioning of broadly tunable and low-cost transverse focusing lens system for MeV-energy electron beams at the ultra-fast electron diffraction (UED) beam-line of the Accelerator Test Facility II of BNL. We exper-imentally demonstrate the independent control over the size and divergence of the electron beam at the sample via tunable quadrupoles. By applying online optimiza-tion, we achieve minimum beam sizes 75 µm from 1 to 13 pC, two orders of magnitude higher charge density than previously achieved using conventional solenoid tech-nique. Finally, we experimentally demonstrate Bragg-diffraction image (BDI) with significant improvement up to 3 times brighter and 2 times sharper BDI peaks via the optimized quadrupoles, improvement larger with higher charge. The result could be crucial for the future single-shot ultra-fast electron microscope development.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP053
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)

Paper

Title

Page

Design of Booster-to-Accumulator Transfer Line for Advanced Light Source Upgrade

2756

C. Sun, Ph. Amstutz, T. Hellert, J.-Y. Jung, S.C. Leemann, J.R. Osborn, M. Placidi, C. Steier, C.A. Swenson, M. Venturini, W. Wan
LBNL, Berkeley, California, USA

Funding: Work supported by the Director Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
For the Advanced Light Source Upgrade, an on-axis swap-out injection is applied to exchange bunch trains between the storage ring and the accumulator ring. To replenish the accumulator ring before the swap-out injection, an electron beam from Linac is first injected into the ALS booster to ramp up the energy, and then transported to the accumulator through the Booster-to-Accumulator (BTA) transfer line. The design of the BTA transfer line is a challenging task as it has to fit within a tight space while accommodating the booster and accumulator rings at different elevations. Moreover, the BTA design needs to meet the optics boundary conditions and ideally minimize the size requirements of vacuum-chamber apertures. In this paper, we will present a design option of the BTA transfer line, which meets both space limitations and beam physics requirements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW111

About •

paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

Export •

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

TUPTS014

SINGLE SHOT CATHODE TRANSVERSE MOMENTUM IMAGING IN PHOTOINJECTORS

1964

SUSPFO016

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

P.W. Huang, Y. Chen, J.D. Good, M. Groß, I.I. Isaev, C. Koschitzki, M. Krasilnikov, S. Lal, X. Li, O. Lishilin, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, H. Shaker, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
D. Filippetto, F. Sannibale
LBNL, Berkeley, California, USA
C.-X. Tang
TUB, Beijing, People’s Republic of China
W. Wan
ShanghaiTech University, Shanghai, People’s Republic of China

In state of the art photoinjector electron sources, cathode performance determines the lower limit of achievable beam emittance. Measuring the thermal emittance at the photocathodes in electron guns is of vital importance for improving the injectors. Traditional methods, like solenoid scan, pepper-pot, need multi-shots and are time-consuming, therefore suffer from machine stability. Here we propose a new method, named cathode transverse momentum imaging. By tuning the gun solenoid focusing, the electrons’ transverse momentum at the cathode is imaged to a downstream screen, which enables a single shot measurement. Several experiments have been done at the Photo Injector Test Facility at DESY in Zeuthen (PITZ) with a Cs2Te cathode. Measurements of cathode transverse momentum, the corresponding spectra, cathode transverse momentum map and its correlation with surface electric field are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS014

About •

paper received ※ 14 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)

THPMP053

Tuning Quadrupoles for Brighter and Sharper Ultra-fast Electron Diffraction Imaging

3571

X. Yang, L. Doom, M.G. Fedurin, Y. Hidaka, J.J. Li, D. Padrazo Jr, T.V. Shaftan, V.V. Smaluk, G.M. Wang, L.-H. Yu, Y. Zhu
BNL, Upton, Long Island, New York, USA
W. Wan
ShanghaiTech University, Shanghai, People’s Republic of China

Funding: BNL LDRD
We report our proof-of-principle design and experi-mental commissioning of broadly tunable and low-cost transverse focusing lens system for MeV-energy electron beams at the ultra-fast electron diffraction (UED) beam-line of the Accelerator Test Facility II of BNL. We exper-imentally demonstrate the independent control over the size and divergence of the electron beam at the sample via tunable quadrupoles. By applying online optimiza-tion, we achieve minimum beam sizes 75 µm from 1 to 13 pC, two orders of magnitude higher charge density than previously achieved using conventional solenoid tech-nique. Finally, we experimentally demonstrate Bragg-diffraction image (BDI) with significant improvement up to 3 times brighter and 2 times sharper BDI peaks via the optimized quadrupoles, improvement larger with higher charge. The result could be crucial for the future single-shot ultra-fast electron microscope development.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP053

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)