FEL2012 - List of Authors (Feng, C.)

Paper

Title

Page

Status of Polarization Control Experiment at Shanghai Deep Ultraviolet Free Electron Laser

245

H.X. Deng, J.H. Chen, Z.M. Dai, Y. Fan, C. Feng, L. Feng, Y.Z. He, T. Lan, B. Liu, D. Wang, X.T. Wang, Z.S. Wang, J.D. Zhang, M. Zhang, M. Zhang, T. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
L. Song
BUAA, Beijing, People's Republic of China

A polarization control experiment using a pair of crossed undulators has bee proposed for the Shanghai deep ultraviolet free electron laser (FEL) test facility. Numerical simulation indicates that, with the phase-shifter between the two crossed undulators, Fourier-Transform-Limited output radiation with 100nJ order pulse energy, 5ps full pulse length and circular polarization degree above 90% could be achieved. The physical design study and the experimental setup status are presented in the paper.

THOC04

Femtosecond X-ray Pulse Duration and Separation Measurement using a Cross-Correlation Technique

Y.T. Ding, F.-J. Decker, Z. Huang, H. Loos, J.J. Welch, J. Wu, F. Zhou
SLAC, Menlo Park, California, USA
P. Emma
LBNL, Berkeley, California, USA
C. Feng
SINAP, Shanghai, People's Republic of China

At the Linac Coherent Light Source (LCLS), the emittance-spoiling foil is a very simple and effective method to control the output x-ray pulse duration [*]. In addition, double slotted foil can be used to generate two femotsecond x-ray pulses with variable time delays. In this paper, we report the first measurement of x-ray pulse duration and double x-ray pulse separation by using a cross-correlation technique between x-rays and electrons [**]. The measured pulse separation can be used to calibrate the foil setup, and pulse duration of less than 3 fs rms has been achieved. This technique can be used to provide critical temporal diagnostics for x-ray experiments that employ the emittance-spoiling foil.
[*] P. Emma et al., PRL 92, 074801 (2004).
[**] G. Geloni et al., DESY 10-008.

Slides THOC04 [0.684 MB]

THPD56

Two-color FEL Generation based on Emittance-spoiler Technique

654

C. Feng, Y.T. Ding, Z. Huang, J. Krzywinski, A.A. Lutman
SLAC, Menlo Park, California, USA

Generation of two-pulse two-color x-ray radiation is attracting much attention within the free-electron laser (FEL) user community. Femtosecond x-ray pulses with variable durations and separation can be simply generated by the emittance-spoiler foil method* at the Linac Coherent Light Source (LCLS). In this paper, we describe three FEL schemes rely on the emittance-spoiler technique for the generation of two intense x-ray pulses with different colors. With a representative realistic set of parameters of LCLS, numerical simulations confirm that two femtosecond x-ray pulses at ten gigawatt level with different wavelengths around 1.8 nm can be generated by these schemes. The central wavelengths of the output pulses can be easily altered by changing strengths of the undulators.
*P. Emma et al., PRL 92, 074801 (2004).

Paper	Title	Page
TUPD10	Status of Polarization Control Experiment at Shanghai Deep Ultraviolet Free Electron Laser	245
	H.X. Deng, J.H. Chen, Z.M. Dai, Y. Fan, C. Feng, L. Feng, Y.Z. He, T. Lan, B. Liu, D. Wang, X.T. Wang, Z.S. Wang, J.D. Zhang, M. Zhang, M. Zhang, T. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China L. Song BUAA, Beijing, People's Republic of China
	A polarization control experiment using a pair of crossed undulators has bee proposed for the Shanghai deep ultraviolet free electron laser (FEL) test facility. Numerical simulation indicates that, with the phase-shifter between the two crossed undulators, Fourier-Transform-Limited output radiation with 100nJ order pulse energy, 5ps full pulse length and circular polarization degree above 90% could be achieved. The physical design study and the experimental setup status are presented in the paper.

THOC04	Femtosecond X-ray Pulse Duration and Separation Measurement using a Cross-Correlation Technique
	Y.T. Ding, F.-J. Decker, Z. Huang, H. Loos, J.J. Welch, J. Wu, F. Zhou SLAC, Menlo Park, California, USA P. Emma LBNL, Berkeley, California, USA C. Feng SINAP, Shanghai, People's Republic of China
	At the Linac Coherent Light Source (LCLS), the emittance-spoiling foil is a very simple and effective method to control the output x-ray pulse duration []. In addition, double slotted foil can be used to generate two femotsecond x-ray pulses with variable time delays. In this paper, we report the first measurement of x-ray pulse duration and double x-ray pulse separation by using a cross-correlation technique between x-rays and electrons []. The measured pulse separation can be used to calibrate the foil setup, and pulse duration of less than 3 fs rms has been achieved. This technique can be used to provide critical temporal diagnostics for x-ray experiments that employ the emittance-spoiling foil. [] P. Emma et al., PRL 92, 074801 (2004). [**] G. Geloni et al., DESY 10-008.
	Slides THOC04 [0.684 MB]

THPD56	Two-color FEL Generation based on Emittance-spoiler Technique	654
	C. Feng, Y.T. Ding, Z. Huang, J. Krzywinski, A.A. Lutman SLAC, Menlo Park, California, USA
	Generation of two-pulse two-color x-ray radiation is attracting much attention within the free-electron laser (FEL) user community. Femtosecond x-ray pulses with variable durations and separation can be simply generated by the emittance-spoiler foil method* at the Linac Coherent Light Source (LCLS). In this paper, we describe three FEL schemes rely on the emittance-spoiler technique for the generation of two intense x-ray pulses with different colors. With a representative realistic set of parameters of LCLS, numerical simulations confirm that two femtosecond x-ray pulses at ten gigawatt level with different wavelengths around 1.8 nm can be generated by these schemes. The central wavelengths of the output pulses can be easily altered by changing strengths of the undulators. *P. Emma et al., PRL 92, 074801 (2004).