FEL2012 - Classification: XFELs

Paper

Title

Page

Spectral Characterization of the FERMI Pulses in the Presence of Electron-beam Phase-space Modulations

213

E. Allaria, S. Di Mitri, W.M. Fawley, E. Ferrari, L. Fröhlich, L. Giannessi, B. Mahieu, G. Penco, C. Spezzani, M. Trovò
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
G. De Ninno, S. Spampinati
University of Nova Gorica, Nova Gorica, Slovenia

As a seeded FEL based on a single stage HGHG configuration, FERMI's FEL-1 has produced very narrow bandwidth FEL pulses in the XUV wavelength region relative to those typical of SASE devices. This important feature of seeded FELs relies however upon the capability to produce high quality electron beams and with clean longitudinal phase spaces. As has been predicted previously, the FEL output spectra can be modified from a simple, nearly transform-limited single spike by modulation and distortions of the longitudinal phase space of the electron beam. In this work we report a study of the FEL spectra recorded at FERMI for various situations showing the effects of phase-space modulation on the FEL properties.

Slides TUOB02 [4.376 MB]

TUOB03

Complete Ultrafast X-ray Pulse Characterization at FELs

A.L. Cavalieri, H. Bromberger, I. Grguras, S. Huber
CFEL, Hamburg, Germany
C. Behrens, S. Düsterer, H. Schlarb
DESY, Hamburg, Germany
C. Bostedt, J.D. Bozek, R.N. Coffee, Y.T. Ding, J.B. Hastings, M.C. Hoffmann, S. Schorb
SLAC, Menlo Park, California, USA
J.T. Costello
DCU, Dublin, Republic of Ireland
L.F. DiMauro
Ohio State University, USA
G. Doumy
ANL, Argonne, USA
W. Helml, R. Kienberger, A.R. Maier, W. Schweinberger
MPQ, Garching, Munich, Germany
N.M. Kabachnik, T. Mazza, M. Meyer, T. Tschentscher
XFEL. EU, Hamburg, Germany
A.K. Kazansky
UPV-EHU, Leioa, Spain

The ability to fully characterize X-ray pulses from free electron-lasers will underpin their exploitation in experiments ranging from single-molecule imaging to extreme timescale X-ray science. This issue is especially acute when confronted with the characteristics of current generation FELs operating on the principle of SASE, as most parameters fluctuate strongly from pulse to pulse. Here, we have extended the techniques of attosecond metrology with the use of single-cycle terahertz (THz) pulses, allowing for simultaneous, in-line, single-shot measurement of both the arrival time and temporal profile of FEL pulses on an absolute scale. The technique is non-invasive and could be incorporated in pump-probe experiments, eventually leading to characterization before and after interaction with most sample environments. Optical-laser-driven THz streaking measurements, revealing X-ray pulse structure shorter than 50 fs FWHM in the soft X-ray regime at FLASH and in the ~ keV range at LCLS will be discussed. With clear potential for improvement in resolution to the sub-10 fs regime, this method will ultimately allow for characterization of the shortest predicted few-femtosecond FEL pulses.

Slides TUOB03 [15.857 MB]

TUPD03

Preliminary FEL Simulation Study for PAL XFEL

229

I. Hwang, J.H. Han, Y.W. Parc
PAL, Pohang, Kyungbuk, Republic of Korea
J. Lee
POSTECH, Pohang, Kyungbuk, Republic of Korea

Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL XFEL) will provide X-ray FEL radiation in a range of 0.1 and 10nm with five undulator beamlines. A undulator section for hard X-ray is designed for 0.1nm SASE FEL. The wakefield effect and its cure by tapering are investigated by tracking simulation. We present FEL simulation study by using GENESIS

TUPD05

Sensitivities of FEL Parameters in LUNEX5 in France by GENESIS Simulation

233

T. Tanikawa, M.-E. Couprie, M. Labat, A. Loulergue
SOLEIL, Gif-sur-Yvette, France
S. Bielawski, C. Evain, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France

LUNEX5 (free-electron Laser (FEL) Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at producing short and intense laser pulse in the soft x-ray region (target wavelength is 13 and 20 nm). This FEL comports either a conventional linear accelerator or a laser wakefield accelerator, and includes innovative schemes such an echo-enable harmonic generation and higher-order harmonics seeding generated in gases to obtain the high spatio-temporal coherent radiation. Sensitivities of FEL radiation property to parameter such as beam energy, energy spread, bunch length, input seed power have been studied by using GENESIS.

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.

FROAI01

European XFEL Working Point Optimization and Status

W. Decking, T. Limberg
DESY, Hamburg, Germany

New results of beam parameter measurements at the injector test facility PITZ at DESY, Zeuthen, and the experience of low emittance beam transport in the LCLS called for less conservative assumptions for the beam quality delivered to the SASE undulators. The change in beam parameters and the interests expressed by the users in the first round of workshops concerning the scientific instruments initiated changes in the undulator systems and SASE wavelength ranges. We summarize the present status and highlight recent developments in the European XFEL design.

Slides FROAI01 [14.926 MB]

Paper	Title	Page
TUOB02	Spectral Characterization of the FERMI Pulses in the Presence of Electron-beam Phase-space Modulations	213
	E. Allaria, S. Di Mitri, W.M. Fawley, E. Ferrari, L. Fröhlich, L. Giannessi, B. Mahieu, G. Penco, C. Spezzani, M. Trovò Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy G. De Ninno, S. Spampinati University of Nova Gorica, Nova Gorica, Slovenia
	As a seeded FEL based on a single stage HGHG configuration, FERMI's FEL-1 has produced very narrow bandwidth FEL pulses in the XUV wavelength region relative to those typical of SASE devices. This important feature of seeded FELs relies however upon the capability to produce high quality electron beams and with clean longitudinal phase spaces. As has been predicted previously, the FEL output spectra can be modified from a simple, nearly transform-limited single spike by modulation and distortions of the longitudinal phase space of the electron beam. In this work we report a study of the FEL spectra recorded at FERMI for various situations showing the effects of phase-space modulation on the FEL properties.
	Slides TUOB02 [4.376 MB]

TUOB03	Complete Ultrafast X-ray Pulse Characterization at FELs
	A.L. Cavalieri, H. Bromberger, I. Grguras, S. Huber CFEL, Hamburg, Germany C. Behrens, S. Düsterer, H. Schlarb DESY, Hamburg, Germany C. Bostedt, J.D. Bozek, R.N. Coffee, Y.T. Ding, J.B. Hastings, M.C. Hoffmann, S. Schorb SLAC, Menlo Park, California, USA J.T. Costello DCU, Dublin, Republic of Ireland L.F. DiMauro Ohio State University, USA G. Doumy ANL, Argonne, USA W. Helml, R. Kienberger, A.R. Maier, W. Schweinberger MPQ, Garching, Munich, Germany N.M. Kabachnik, T. Mazza, M. Meyer, T. Tschentscher XFEL. EU, Hamburg, Germany A.K. Kazansky UPV-EHU, Leioa, Spain
	The ability to fully characterize X-ray pulses from free electron-lasers will underpin their exploitation in experiments ranging from single-molecule imaging to extreme timescale X-ray science. This issue is especially acute when confronted with the characteristics of current generation FELs operating on the principle of SASE, as most parameters fluctuate strongly from pulse to pulse. Here, we have extended the techniques of attosecond metrology with the use of single-cycle terahertz (THz) pulses, allowing for simultaneous, in-line, single-shot measurement of both the arrival time and temporal profile of FEL pulses on an absolute scale. The technique is non-invasive and could be incorporated in pump-probe experiments, eventually leading to characterization before and after interaction with most sample environments. Optical-laser-driven THz streaking measurements, revealing X-ray pulse structure shorter than 50 fs FWHM in the soft X-ray regime at FLASH and in the ~ keV range at LCLS will be discussed. With clear potential for improvement in resolution to the sub-10 fs regime, this method will ultimately allow for characterization of the shortest predicted few-femtosecond FEL pulses.
	Slides TUOB03 [15.857 MB]

TUPD03	Preliminary FEL Simulation Study for PAL XFEL	229
	I. Hwang, J.H. Han, Y.W. Parc PAL, Pohang, Kyungbuk, Republic of Korea J. Lee POSTECH, Pohang, Kyungbuk, Republic of Korea
	Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL XFEL) will provide X-ray FEL radiation in a range of 0.1 and 10nm with five undulator beamlines. A undulator section for hard X-ray is designed for 0.1nm SASE FEL. The wakefield effect and its cure by tapering are investigated by tracking simulation. We present FEL simulation study by using GENESIS

TUPD05	Sensitivities of FEL Parameters in LUNEX5 in France by GENESIS Simulation	233
	T. Tanikawa, M.-E. Couprie, M. Labat, A. Loulergue SOLEIL, Gif-sur-Yvette, France S. Bielawski, C. Evain, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
	LUNEX5 (free-electron Laser (FEL) Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at producing short and intense laser pulse in the soft x-ray region (target wavelength is 13 and 20 nm). This FEL comports either a conventional linear accelerator or a laser wakefield accelerator, and includes innovative schemes such an echo-enable harmonic generation and higher-order harmonics seeding generated in gases to obtain the high spatio-temporal coherent radiation. Sensitivities of FEL radiation property to parameter such as beam energy, energy spread, bunch length, input seed power have been studied by using GENESIS.

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.

FROAI01	European XFEL Working Point Optimization and Status
	W. Decking, T. Limberg DESY, Hamburg, Germany
	New results of beam parameter measurements at the injector test facility PITZ at DESY, Zeuthen, and the experience of low emittance beam transport in the LCLS called for less conservative assumptions for the beam quality delivered to the SASE undulators. The change in beam parameters and the interests expressed by the users in the first round of workshops concerning the scientific instruments initiated changes in the undulator systems and SASE wavelength ranges. We summarize the present status and highlight recent developments in the European XFEL design.
	Slides FROAI01 [14.926 MB]