FEL2015 - List of Keywords (focusing)

Paper	Title	Other Keywords	Page
MOP054	Wake Field Potentials of 'Dechirpers'	wakefield, FEL, experiment, electron	157
	A. Novokhatski SLAC, Menlo Park, California, USA
	Funding: This work was supported by Department of Energy Contract No. DOE-AC03-76SF00515. A corrugated structure, which is used on 'dechirpers' is usually a pipe or two plates with small corrugations (bumps) on the walls. There is a good single-mode description of the wake potentials excited by a relativistic bunch if the wave length of the mode is much longer than the distance between the bumps in the pipe. However, ultra-short bunches, which are now used in FELs, excite much higher frequency fields and the corresponding wake potentials will be very different from single-mode description. We made analyzes of these wake potentials based on a numerical solution of Maxwell's equations. The behavior of the wake fields of ultra-short bunches in corrugated structures is not much different from the fields excited usually in accelerating structures where the wake potentials are described by the exponential function. As we increase the bunch length, the wake potentials slowly transform to the form of a single mode. For a practical application we present results for a 'dechirper', which will be soon installed at LCLS. We also carried out calculations for a similar device, that was installed and measured at the Pohang Accelerator Laboratory, Korea. We find very good agreement with the experimental results.
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TUP027	Facility Upgrades for the High Harmonic Echo Program at SLAC's NLCTA	laser, undulator, radiation, electron	422
	B.W. Garcia, M.P. Dunning, C. Hast, E. Hemsing, T.O. Raubenheimer SLAC, Menlo Park, California, USA D. Xiang Shanghai Jiao Tong University, Shanghai, People's Republic of China
	The Echo program currently underway at SLAC's NLCTA test accelerator aims to use Echo-Enabled Harmonic Generation (EEHG) to produce considerable bunching in the electron beam at high harmonics of a 2.4um seed laser. The production of such high harmonics in the EUV wavelength range necessitates an efficient radiator and associated light diagnostics to accurately characterize and tune the echo effect. We have installed and commissioned the Visible to Infrared SASE Amplifier (VISA) undulator, a strong focusing two meter long planar undulator of Halbach array design with 1.8cm period length. To characterize the output radiation, we have designed, built, and calibrated a grazing incidence EUV spectrometer which operates between 12-120nm with resolution sufficient to resolve individual harmonics. An absolute wavelength calibration is achieved by using both EEHG and High Gain Harmonic Generation (HGHG) signals from the undulator.
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Paper

Title

Other Keywords

Page

MOP054

Wake Field Potentials of 'Dechirpers'

wakefield, FEL, experiment, electron

157

A. Novokhatski
SLAC, Menlo Park, California, USA

Funding: This work was supported by Department of Energy Contract No. DOE-AC03-76SF00515.
A corrugated structure, which is used on 'dechirpers' is usually a pipe or two plates with small corrugations (bumps) on the walls. There is a good single-mode description of the wake potentials excited by a relativistic bunch if the wave length of the mode is much longer than the distance between the bumps in the pipe. However, ultra-short bunches, which are now used in FELs, excite much higher frequency fields and the corresponding wake potentials will be very different from single-mode description. We made analyzes of these wake potentials based on a numerical solution of Maxwell's equations. The behavior of the wake fields of ultra-short bunches in corrugated structures is not much different from the fields excited usually in accelerating structures where the wake potentials are described by the exponential function. As we increase the bunch length, the wake potentials slowly transform to the form of a single mode. For a practical application we present results for a 'dechirper', which will be soon installed at LCLS. We also carried out calculations for a similar device, that was installed and measured at the Pohang Accelerator Laboratory, Korea. We find very good agreement with the experimental results.

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reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP027

Facility Upgrades for the High Harmonic Echo Program at SLAC's NLCTA

laser, undulator, radiation, electron

422

B.W. Garcia, M.P. Dunning, C. Hast, E. Hemsing, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
D. Xiang
Shanghai Jiao Tong University, Shanghai, People's Republic of China

The Echo program currently underway at SLAC's NLCTA test accelerator aims to use Echo-Enabled Harmonic Generation (EEHG) to produce considerable bunching in the electron beam at high harmonics of a 2.4um seed laser. The production of such high harmonics in the EUV wavelength range necessitates an efficient radiator and associated light diagnostics to accurately characterize and tune the echo effect. We have installed and commissioned the Visible to Infrared SASE Amplifier (VISA) undulator, a strong focusing two meter long planar undulator of Halbach array design with 1.8cm period length. To characterize the output radiation, we have designed, built, and calibrated a grazing incidence EUV spectrometer which operates between 12-120nm with resolution sufficient to resolve individual harmonics. An absolute wavelength calibration is achieved by using both EEHG and High Gain Harmonic Generation (HGHG) signals from the undulator.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)