IPAC2017 - List of Authors (Qin, W.)

Paper	Title	Page
TUPAB129	Optimization of Beam Dynamics for an S-Band Ultra-High Gradient Photoinjector	1626
	A.D. Cahill, A. Fukasawa, J.B. Rosenzweig UCLA, Los Angeles, California, USA C. Limborg, W. Qin SLAC, Menlo Park, California, USA
	Funding: Work Supported by DOE/SU Contract DE-AC02-76-SF00515, US NSF Award PHY-1549132, the Center for Bright Beams, and DOE SCGSR Fellowship. Travel to IPAC'17 supported by the Div. of Phys. of the US NSF (Accel. Sci. Prog.) and the Div. of Beam Phys. of the APS New electron sources with improved brightness are desired to enhance the capabilities of FELs, making them more compact and fully coherent. Improvements in electron source brightness can be achieved by increasing electric fields on the cathode of photo-emitted electron guns. Recent developments in pulsed RF accelerator structures show that very high gradient fields can be sustained with low breakdown rates by operating at cryo-temperatures, which when applied to photoguns will lead to a large increase in the electron beam brightness. In particular, our simulations show that when operating with a peak gradient field of 240 MV/m on the cathode of an S-band, electron beam brightness of 80~nC/(mm· mrad)²/mm can be achieved with 100~pC bunches. In this paper, we present the design and optimization of an 1.x cell S-Band RF photoinjector, where the x varies from 4-6. The optimization in brightness has been obtained by using a multi-objective genetic algorithm on the solutions calculated with the ASTRA code. We calculate the optimum length of the rf gun, position of accelerating structure, and laser pulse dimensions for a variety of charges.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB129
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THPAB078	Beam Dynamics Studies of the Transverse Gradient Undulator and Its Application to Suppression of Microbunching Instability	3895
	T. Liu, Y. Ding, Z. Huang, W. Qin SLAC, Menlo Park, California, USA T. Liu University of Chinese Academy of Sciences, Beijing, People's Republic of China T. Liu, D. Wang SINAP, Shanghai, People's Republic of China
	A transverse gradient undulator (TGU) which was initially proposed for high gain free electron lasers (FELs) driven by electron beams with relatively large energy spread, can be extended to the application of beam dynamics, such as phase-merging enhanced harmonic generation FEL and suppression of microbunching instability. In this contribution we present beam dynamics studies of the TGU, analyze the resulting focusing and dispersion, and discuss the effects of an additional corrector on the TGU. As an application to beam dynamics, we show a feasible transport system based on the TGU as a reversible electron beam heater to suppress the microbunching instability of the electron beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB078
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Paper

Title

Page

Optimization of Beam Dynamics for an S-Band Ultra-High Gradient Photoinjector

1626

A.D. Cahill, A. Fukasawa, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
C. Limborg, W. Qin
SLAC, Menlo Park, California, USA

Funding: Work Supported by DOE/SU Contract DE-AC02-76-SF00515, US NSF Award PHY-1549132, the Center for Bright Beams, and DOE SCGSR Fellowship. Travel to IPAC'17 supported by the Div. of Phys. of the US NSF (Accel. Sci. Prog.) and the Div. of Beam Phys. of the APS
New electron sources with improved brightness are desired to enhance the capabilities of FELs, making them more compact and fully coherent. Improvements in electron source brightness can be achieved by increasing electric fields on the cathode of photo-emitted electron guns. Recent developments in pulsed RF accelerator structures show that very high gradient fields can be sustained with low breakdown rates by operating at cryo-temperatures, which when applied to photoguns will lead to a large increase in the electron beam brightness. In particular, our simulations show that when operating with a peak gradient field of 240 MV/m on the cathode of an S-band, electron beam brightness of 80~nC/(mm· mrad)²/mm can be achieved with 100~pC bunches. In this paper, we present the design and optimization of an 1.x cell S-Band RF photoinjector, where the x varies from 4-6. The optimization in brightness has been obtained by using a multi-objective genetic algorithm on the solutions calculated with the ASTRA code. We calculate the optimum length of the rf gun, position of accelerating structure, and laser pulse dimensions for a variety of charges.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB129

Export •

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

THPAB078

Beam Dynamics Studies of the Transverse Gradient Undulator and Its Application to Suppression of Microbunching Instability

3895

T. Liu, Y. Ding, Z. Huang, W. Qin
SLAC, Menlo Park, California, USA
T. Liu
University of Chinese Academy of Sciences, Beijing, People's Republic of China
T. Liu, D. Wang
SINAP, Shanghai, People's Republic of China

A transverse gradient undulator (TGU) which was initially proposed for high gain free electron lasers (FELs) driven by electron beams with relatively large energy spread, can be extended to the application of beam dynamics, such as phase-merging enhanced harmonic generation FEL and suppression of microbunching instability. In this contribution we present beam dynamics studies of the TGU, analyze the resulting focusing and dispersion, and discuss the effects of an additional corrector on the TGU. As an application to beam dynamics, we show a feasible transport system based on the TGU as a reversible electron beam heater to suppress the microbunching instability of the electron beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB078

Export •

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