FEL2011 - List of Authors (Evain, C.)

Paper

Title

Page

Seeding Schemes on the French FEL Project LUNEX5

198

C. Evain, F. Briquez, M.-E. Couprie, M. Labat, A. Loulergue
SOLEIL, Gif-sur-Yvette, France
V. Malka
LOA, Palaiseau, France

LUNEX5 is a single pass FEL project producing coherent synchrotron radiation with, in a first step, an electron bunch accelerated in conventional RF cavities up to 300 MeV. It is planned to work in a seeded configuration where the longitudinal coherence of the emitted light is improved and the gain length reduced, compared to the SASE configuration (Self-Amplified Spontaneous Emission). Two seeding schemes are considered: High order Harmonic in Gas seeding and EEHG scheme (Echo Enabled Harmonic Generation). Preliminary simulation results indicate that these two schemes permit to reach the saturation below a wavelength of 7 nm, and with less undulator periods for the EEHG scheme. Finally, the feasibility of plasma acceleration based FEL will also be investigated on this facility.

TUPA09

LUNEX5: A FEL Project Towards the Fifth Generation in France

208

M.-E. Couprie, C. Benabderrahmane, F. Briquez, J. Daillant, J.-C. Denard, C. Evain, P. Eymard, F. Ferrari, J.-M. Filhol, M. Labat, A. Loulergue, P. Marchand, C. Miron, P. Morin, F. Polack
SOLEIL, Gif-sur-Yvette, France
S. Bielawski, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
B. Carré
CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
N. Delerue, R. Roux, A. Variola
LAL, Orsay, France
G. Lambert, V. Malka, A. Rousse
LOA, Palaiseau, France
J. Lüning
CCPMR, Paris, France

LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating the production of short intense and coherent pulses in the soft X rays region (down to 7 nm on the fifth harmonic). It comprises a free electron laser in the seeded configuration (High order Harmonic in Gas seeding and Echo Enable Harmonic Generation) using a conventional linear accelerator of 300 MeV. The FEL beamline including 15 m of in vacuum (potentially cryogenic undulators) of 15 and 30 mm period is designed so as to also accommodate a Laser Wake Field Accelerator (LWFA) ranging from 0.3 to 1 GeV, relying on electron beam parameters produced and accelerated by either the 60 TW laser of LOA or by the 10 PW APOLLON laser of ILE. After the completion and testing of the FEL with the conventional accelerator installed inside the SOLEIL booster inner area, the FEL line can be transported to a LWFA. A laser could alternatively be implemented at SOLEIL for starting testing the principles of a fifth generation light source.

WEOC4

Intense Coherent THz Synchrotron Radiation Induced by a Storage Ring FEL Seeded with a Femtosecond Laser

M. Hosaka, Y. Taira, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
M. Adachi, M. Katoh, T. Tanikawa, H. Zen
UVSOR, Okazaki, Japan
S. Bielawski, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
C. Evain
SOLEIL, Gif-sur-Yvette, France

Very recently, we have succeeded in seeding a resonator FEL by injecting an external femtosecond laser at the UVSOR-II storage ring [1]. Intense coherent synchrotron radiation (CSR) in the THz region from a bending magnet was observed when the seeded FEL was operated in the pulsed Q-switch mode [2]. We have also found that the CSR intensity depends on the pulse duration of the seed laser. The CSR intensity is enhanced with short pulse ~200 fsec and suppressed with longer pulse ~200 psec. Simultaneous measurement of the terahertz radiation and the FEL pulse reveals that the radiation is emitted in the growing phase of the Q-switch FEL pulse. We think that the CSR comes from repetitive interactions between the laser pulse and the electron bunch as the short pulse laser growth in the optical cavity. In the presentation, we will also discuss the production mechanism of the CSR.
[1] C. Szwaj et al., FEL2011, TUPB05, in this conference.
[2] H. Zen et al., FEL2011, TUPA13, in this conference.

Slides WEOC4 [2.715 MB]

WEPA14

Effect of a Quasiperiodic Undulator on FEL Radiation

352

F. Briquez, C. Benabderrahmane, M.-E. Couprie, C. Evain, M. Labat
SOLEIL, Gif-sur-Yvette, France

The operation of conventional undulators results from an interference scheme in order to generate radiation of a fundamental wavelength and its harmonics. Whereas these harmonics are in most of the cases useful to reach higher energies, it is profitable in specific configurations to shift or reduce them, for instance to limit power on optics or to distinguish between one or two photon process in user experiments. This can be performed by so-called quasi-periodic undulators in which the periodicity of the magnetic field is destructed. In this case, the field amplitude is reduced on a few positions among the axis, inducing a destruction of the interference scheme. Such undulators are commonly used to generate spontaneous emission in synchrotron radiation facilities but could also be installed in Free Electron Lasers. The emitted radiation of the quasi-periodic undulator is compared with the usual configuration one, in the case of LUNEX5. Simulations using GENESIS code are described and results are discussed.

Paper	Title	Page
TUPA06	Seeding Schemes on the French FEL Project LUNEX5	198
	C. Evain, F. Briquez, M.-E. Couprie, M. Labat, A. Loulergue SOLEIL, Gif-sur-Yvette, France V. Malka LOA, Palaiseau, France
	LUNEX5 is a single pass FEL project producing coherent synchrotron radiation with, in a first step, an electron bunch accelerated in conventional RF cavities up to 300 MeV. It is planned to work in a seeded configuration where the longitudinal coherence of the emitted light is improved and the gain length reduced, compared to the SASE configuration (Self-Amplified Spontaneous Emission). Two seeding schemes are considered: High order Harmonic in Gas seeding and EEHG scheme (Echo Enabled Harmonic Generation). Preliminary simulation results indicate that these two schemes permit to reach the saturation below a wavelength of 7 nm, and with less undulator periods for the EEHG scheme. Finally, the feasibility of plasma acceleration based FEL will also be investigated on this facility.

TUPA09	LUNEX5: A FEL Project Towards the Fifth Generation in France	208
	M.-E. Couprie, C. Benabderrahmane, F. Briquez, J. Daillant, J.-C. Denard, C. Evain, P. Eymard, F. Ferrari, J.-M. Filhol, M. Labat, A. Loulergue, P. Marchand, C. Miron, P. Morin, F. Polack SOLEIL, Gif-sur-Yvette, France S. Bielawski, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France B. Carré CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France N. Delerue, R. Roux, A. Variola LAL, Orsay, France G. Lambert, V. Malka, A. Rousse LOA, Palaiseau, France J. Lüning CCPMR, Paris, France
	LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating the production of short intense and coherent pulses in the soft X rays region (down to 7 nm on the fifth harmonic). It comprises a free electron laser in the seeded configuration (High order Harmonic in Gas seeding and Echo Enable Harmonic Generation) using a conventional linear accelerator of 300 MeV. The FEL beamline including 15 m of in vacuum (potentially cryogenic undulators) of 15 and 30 mm period is designed so as to also accommodate a Laser Wake Field Accelerator (LWFA) ranging from 0.3 to 1 GeV, relying on electron beam parameters produced and accelerated by either the 60 TW laser of LOA or by the 10 PW APOLLON laser of ILE. After the completion and testing of the FEL with the conventional accelerator installed inside the SOLEIL booster inner area, the FEL line can be transported to a LWFA. A laser could alternatively be implemented at SOLEIL for starting testing the principles of a fifth generation light source.

WEOC4	Intense Coherent THz Synchrotron Radiation Induced by a Storage Ring FEL Seeded with a Femtosecond Laser
	M. Hosaka, Y. Taira, Y. Takashima, N. Yamamoto Nagoya University, Nagoya, Japan M. Adachi, M. Katoh, T. Tanikawa, H. Zen UVSOR, Okazaki, Japan S. Bielawski, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France C. Evain SOLEIL, Gif-sur-Yvette, France
	Very recently, we have succeeded in seeding a resonator FEL by injecting an external femtosecond laser at the UVSOR-II storage ring [1]. Intense coherent synchrotron radiation (CSR) in the THz region from a bending magnet was observed when the seeded FEL was operated in the pulsed Q-switch mode [2]. We have also found that the CSR intensity depends on the pulse duration of the seed laser. The CSR intensity is enhanced with short pulse ~200 fsec and suppressed with longer pulse ~200 psec. Simultaneous measurement of the terahertz radiation and the FEL pulse reveals that the radiation is emitted in the growing phase of the Q-switch FEL pulse. We think that the CSR comes from repetitive interactions between the laser pulse and the electron bunch as the short pulse laser growth in the optical cavity. In the presentation, we will also discuss the production mechanism of the CSR. [1] C. Szwaj et al., FEL2011, TUPB05, in this conference. [2] H. Zen et al., FEL2011, TUPA13, in this conference.
	Slides WEOC4 [2.715 MB]

WEPA14	Effect of a Quasiperiodic Undulator on FEL Radiation	352
	F. Briquez, C. Benabderrahmane, M.-E. Couprie, C. Evain, M. Labat SOLEIL, Gif-sur-Yvette, France
	The operation of conventional undulators results from an interference scheme in order to generate radiation of a fundamental wavelength and its harmonics. Whereas these harmonics are in most of the cases useful to reach higher energies, it is profitable in specific configurations to shift or reduce them, for instance to limit power on optics or to distinguish between one or two photon process in user experiments. This can be performed by so-called quasi-periodic undulators in which the periodicity of the magnetic field is destructed. In this case, the field amplitude is reduced on a few positions among the axis, inducing a destruction of the interference scheme. Such undulators are commonly used to generate spontaneous emission in synchrotron radiation facilities but could also be installed in Free Electron Lasers. The emitted radiation of the quasi-periodic undulator is compared with the usual configuration one, in the case of LUNEX5. Simulations using GENESIS code are described and results are discussed.