FEL2012 - List of Authors (Marinelli, A.)

Paper

Title

Page

Generation of Longitudinally Coherent Ultra High Power X-Ray FEL Pulses by Phase and Amplitude Mixing

237

J. Wu, C. Pellegrini
SLAC, Menlo Park, California, USA
A. Marinelli
UCLA, Los Angeles, California, USA

Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515.
We study an improved-SASE (iSASE) scheme to generate narrow bandwidth Free Electron Laser (FEL) by introducing phase shifter between the undulator segments to speed up the slippage. Due to the shift of the FEL pulse with respect to the electron bunch, spikes with phase relation develop; therefore the coherent length increases faster. Furthermore, due to the similarity of these spikes in the temporal domain with respect to the spikes generated in the previous sections, the spectrum of such an FEL containing a regular temporal spike train is intrinsically narrower than that of a conventional SASE FEL. Here, we report study results for a soft x-ray FEL at 6 nm and a hard x-ray at 0.15 nm. With a narrower bandwidth, the FEL responds to a tapered undulator more efficiently than a conventional SASE FEL does. This then make it possible to reach high power. Analysis is carried out with GENESIS numerical simulation as well as 1-D analytical calculation.

WEOBI01

Single-shot Reconstruction of Beam Microbunching by Phase-retrieval of Coherent Transition Radiation images

A. Marinelli, G. Andonian, J. Miao, F.H. O'Shea, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
M.P. Dunning, C. Hast, E. Hemsing, S.P. Weathersby, D. Xiang
SLAC, Menlo Park, California, USA

We describe a technique for the reconstruction of the transverse spatial distribution of microbunching in a relativistic electron beam, and report on its experimental demonstration at the NLCTA test accelerator at SLAC. This technique relies on an oversampling phase retrieval method on a far field coherent optical transition radiation image. This method has a number of applications as an diagnostic for the FEL amplification process and in the imaging of compressed beams. We report on the experimental demonstration of this method in the case of microbunching generated by the interaction of an external laser pulse with an electron beam traversing an undulator.

Slides WEOBI01 [2.772 MB]

Paper	Title	Page
TUPD07	Generation of Longitudinally Coherent Ultra High Power X-Ray FEL Pulses by Phase and Amplitude Mixing	237
	J. Wu, C. Pellegrini SLAC, Menlo Park, California, USA A. Marinelli UCLA, Los Angeles, California, USA
	Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515. We study an improved-SASE (iSASE) scheme to generate narrow bandwidth Free Electron Laser (FEL) by introducing phase shifter between the undulator segments to speed up the slippage. Due to the shift of the FEL pulse with respect to the electron bunch, spikes with phase relation develop; therefore the coherent length increases faster. Furthermore, due to the similarity of these spikes in the temporal domain with respect to the spikes generated in the previous sections, the spectrum of such an FEL containing a regular temporal spike train is intrinsically narrower than that of a conventional SASE FEL. Here, we report study results for a soft x-ray FEL at 6 nm and a hard x-ray at 0.15 nm. With a narrower bandwidth, the FEL responds to a tapered undulator more efficiently than a conventional SASE FEL does. This then make it possible to reach high power. Analysis is carried out with GENESIS numerical simulation as well as 1-D analytical calculation.

WEOBI01	Single-shot Reconstruction of Beam Microbunching by Phase-retrieval of Coherent Transition Radiation images
	A. Marinelli, G. Andonian, J. Miao, F.H. O'Shea, J.B. Rosenzweig UCLA, Los Angeles, California, USA M.P. Dunning, C. Hast, E. Hemsing, S.P. Weathersby, D. Xiang SLAC, Menlo Park, California, USA
	We describe a technique for the reconstruction of the transverse spatial distribution of microbunching in a relativistic electron beam, and report on its experimental demonstration at the NLCTA test accelerator at SLAC. This technique relies on an oversampling phase retrieval method on a far field coherent optical transition radiation image. This method has a number of applications as an diagnostic for the FEL amplification process and in the imaging of compressed beams. We report on the experimental demonstration of this method in the case of microbunching generated by the interaction of an external laser pulse with an electron beam traversing an undulator.
	Slides WEOBI01 [2.772 MB]