IPAC2012 - List of Authors (Qin, Q.)

Paper

Title

Page

Performance and Prospects of BEPCII

1030

Q. Qin
IHEP, Beijing, People's Republic of China

BEPCII, the upgrade project of Beijing Electron Positron Collider (BEPC), has been put into operation for both high energy physics experiments as well as synchrotron radiation application since its completion in 2009. The peak luminosity reaches 6.5*10³² cm^-2 s^-1 at 1.89 GeV with e⁺e⁻ collisions of each beam current 700 mA. The collider operates for dedicated synchrotron radiation mode with 250 mA electron beams at 2.5 GeV. The performance of BEPCII should be reported and the measures to upgrade its luminosity described.

Slides TUYA03 [5.529 MB]

TUPPP083

Multi-Dimensional Optimization of a Tapered Free Electron Laser

1783

Y. Jiao, J. Wu
SLAC, Menlo Park, California, USA
Q. Qin
IHEP, Beijing, People's Republic of China

Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. In this paper, we report a multi-dimensional optimizer to maximize the radiation power in a tapered FEL by searching for an optimal taper profile as well as a reasonable variation in electron beam radius. Applications of the proposed multi-dimensional optimization to the terawatt-level, tapered FELs with LCLS-like electron beam parameters are presented, and the proposed optimization scheme is compared with the GINGER’s self-design taper algorithm. At the end, the dependence of the available maximum radiation power on various parameters of the initial electron beam, the initial radiation field and the undulator system is summarized.

TUPPP084

Efficiency Enhancement in a Tapered Free Electron Laser by Varying the Electron Beam Radius

1786

Y. Jiao, J. Wu
SLAC, Menlo Park, California, USA
Q. Qin
IHEP, Beijing, People's Republic of China

Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. An in-depth understanding of the tapering-related physics is required to explore the full potential of a tapered FEL, not only by tapering the undulator parameters in longitudinal dimension, but also optimizing the transverse effects. Based on the modified 1D FEL model and time-steady numerical simulations, we study the contribution of the variation in electron beam radius and the related transverse effects. Taking a terawatt-level, 120-m tapered FEL as example, we demonstrate that a reasonably varied, instead of a constant, electron beam radius along the undulator helps to improve the optical guiding and thus the radiation output.

Paper	Title	Page
TUYA03	Performance and Prospects of BEPCII	1030
	Q. Qin IHEP, Beijing, People's Republic of China
	BEPCII, the upgrade project of Beijing Electron Positron Collider (BEPC), has been put into operation for both high energy physics experiments as well as synchrotron radiation application since its completion in 2009. The peak luminosity reaches 6.5*10³² cm^-2 s^-1 at 1.89 GeV with e⁺e⁻ collisions of each beam current 700 mA. The collider operates for dedicated synchrotron radiation mode with 250 mA electron beams at 2.5 GeV. The performance of BEPCII should be reported and the measures to upgrade its luminosity described.
	Slides TUYA03 [5.529 MB]

TUPPP083	Multi-Dimensional Optimization of a Tapered Free Electron Laser	1783
	Y. Jiao, J. Wu SLAC, Menlo Park, California, USA Q. Qin IHEP, Beijing, People's Republic of China
	Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. In this paper, we report a multi-dimensional optimizer to maximize the radiation power in a tapered FEL by searching for an optimal taper profile as well as a reasonable variation in electron beam radius. Applications of the proposed multi-dimensional optimization to the terawatt-level, tapered FELs with LCLS-like electron beam parameters are presented, and the proposed optimization scheme is compared with the GINGER’s self-design taper algorithm. At the end, the dependence of the available maximum radiation power on various parameters of the initial electron beam, the initial radiation field and the undulator system is summarized.

TUPPP084	Efficiency Enhancement in a Tapered Free Electron Laser by Varying the Electron Beam Radius	1786
	Y. Jiao, J. Wu SLAC, Menlo Park, California, USA Q. Qin IHEP, Beijing, People's Republic of China
	Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. An in-depth understanding of the tapering-related physics is required to explore the full potential of a tapered FEL, not only by tapering the undulator parameters in longitudinal dimension, but also optimizing the transverse effects. Based on the modified 1D FEL model and time-steady numerical simulations, we study the contribution of the variation in electron beam radius and the related transverse effects. Taking a terawatt-level, 120-m tapered FEL as example, we demonstrate that a reasonably varied, instead of a constant, electron beam radius along the undulator helps to improve the optical guiding and thus the radiation output.