FEL2015 - List of Authors (Giannessi, L.)

Paper

Title

Page

The Fermi Seeded FEL Facility: Operational Experience and Future Perspectives

57

L. Giannessi, E. Allaria, L. Badano, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, P. Cinquegrana, M. Coreno, R. Cucini, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, P. Finetti, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, F. Iazzourene, M. Kiskinova, S. Krecic, M. Lonza, N. Mahne, M. Manfredda, C. Masciovecchio, M. Milloch, F. Parmigiani, E. Pedersoli, G. Penco, L. Pivetta, O. Plekan, M. Predonzani, K.C. Prince, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, E. Roussel, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, M. Svandrlik, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

FERMI is the seeded FEL user facility in Trieste, Italy, producing photons from the VUV to the soft X-rays with a high degree of coherence and spectral stability. Both FEL lines, FEL-1 and FEL-2, are available for users, down to the shortest wavelength of 4 nm. We report on the completion of the commissioning of the high energy FEL line, FEL-2, on the most recent progress obtained on FEL-1 and on the operational experience for users, in particular those requiring specific FEL configurations, such as two-colour experiments. We will also give a perspective on the improvements and upgrades which have been triggered based on our experience, aiming to maintain as well as to constantly improve the performance of the facility for our user community.

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MOP034

Beam Optics Measurements at FERMI by using Wire-Scanner

101

G. Penco, A. Abrami, I. Cudin, S. Di Mitri, M. Ferianis, E. Ferrari, G. Gaio, L. Giannessi, S. Grulja, R. Sauro, L. Sturari
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
E. Ferrari
Università degli Studi di Trieste, Trieste, Italy
L. Giannessi
ENEA C.R. Frascati, Frascati (Roma), Italy
G.L. Orlandi, C. Ozkan Loch
PSI, Villigen PSI, Switzerland

Measuring and controlling the electron beam optics is an important ingredient to guarantee high performance of a free-electron laser. In the FERMI linac, the Twiss parameters and the transverse emittances are routinely measured by detecting the beam spot size as a function of a scanning quadrupole placed upstream (i.e. quadrupole scan method). The beam spot size is usually measured with an OTR screen that unfortunately suffers from coherent optical transition radiation (C-OTR) that introduces spurious light and corrupts the image. Moreover, the beam size at the end of the FERMI linac is focused to a few tens of microns and this makes it difficult to precisely measure it with the OTR system, which has an estimated resolution of 20um. For this reason, a wire-scanner system has been installed at the end of the linac just in the waist of the optics channel. The wire-scanner is a SwissFEL prototype installed in FERMI in order to study the hardware and beam loss monitor performances at the GeV energy scale. The beam optics measurements performed with the wire-scanner is here presented, and the obtained results are more in agreement with the theoretical expectations. A more reliable beam optics estimation at the end of the linac has allowed to better match it to the nominal lattice and transport it up to the undulator chain, providing important benefits to the FEL performance.

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TUB01

Spectro-Temporal Control and Characterization of XUV Pulses from a Seeded Free-Electron Laser

D. Gauthier, E. Allaria, P. Cinquegrana, M.B. Danailov, G. De Ninno, A.A. Demidovich, E. Ferrari, L. Giannessi, G. Penco, P. Rebernik Ribič, P. Sigalotti
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
G. De Ninno
University of Nova Gorica, Nova Gorica, Slovenia
E. Ferrari
Università degli Studi di Trieste, Trieste, Italy
L. Giannessi
ENEA C.R. Frascati, Frascati (Roma), Italy
B. Mahieu
LOA, Palaiseau, France

In ultrafast X-ray science, the knowledge of and the ability to control the spectro-temporal properties of individual X-ray pulses, such as those from free-electron lasers (FELs), constitute a fundamental aspect in the design of new experiments aimed at probing matter with femtosecond temporal resolution. Recent works carried out at the seeded free-electron laser FERMI in Trieste demonstrate that such a device is able to generate light pulses in the XUV spectral region, whose spectro-temporal content can be precisely controlled. These examples rely on the manipulation of the seed laser used as coherent input signal to drive the FEL process. The first experiment demonstrates the phase control of the FEL output pulse through the manipulation of the seed laser frequency chirp. The second is the implementation of a single-shot method for complete pulse characterization. These experiments show not only the first direct evidence of the temporal coherence and the generation of Fourier limited pulses, but they demonstrate the ability to control and shape the spectro-temporal content of the pulses. Consequently, a seeded FEL can be really considered as a laser-like source providing high peak power light pulses. A fine tuning of the light pulses opens the door to new kinds of experiments in the field of coherent nonlinear optics and coherent quantum control.

Slides TUB01 [4.430 MB]

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TUB04

Influence of a Non-Uniform Longitudinal Heating on High Brightness Electron Beams for FEL

E. Ferrari
Università degli Studi di Trieste, Trieste, Italy
E. Allaria, M.B. Danailov, G. De Ninno, S. Di Mitri, D. Gauthier, L. Giannessi, G. Penco, E. Roussel, M. Veronese
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
G. De Ninno, D. Gauthier
University of Nova Gorica, Nova Gorica, Slovenia
L. Giannessi
ENEA C.R. Frascati, Frascati (Roma), Italy

Laser-heater systems are essential tools to control and optimize high-gain free electron lasers (FELs), working in the x-ray wavelength range. Indeed, these systems induce a controllable heating of the energy spread of the electron bunch. The heating allows in turn to suppress longitudinal microbunching instabilities limiting the FEL performance. In this communication, we show that a long-wavelength energy modulation of the electron beam induced by the laser heater can be preserved until the beam entrance in the undulators, affecting the FEL emission process. This non-uniform longitudinal heating can be exploited to investigate the electron- beam microbunching in the linac, as well as to control the FEL spectral properties. Here, we present experimental, analytical and numerical studies carried out at FERMI.

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Paper	Title	Page
MOP013	The Fermi Seeded FEL Facility: Operational Experience and Future Perspectives	57
	L. Giannessi, E. Allaria, L. Badano, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, P. Cinquegrana, M. Coreno, R. Cucini, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, P. Finetti, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, F. Iazzourene, M. Kiskinova, S. Krecic, M. Lonza, N. Mahne, M. Manfredda, C. Masciovecchio, M. Milloch, F. Parmigiani, E. Pedersoli, G. Penco, L. Pivetta, O. Plekan, M. Predonzani, K.C. Prince, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, E. Roussel, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, M. Svandrlik, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	FERMI is the seeded FEL user facility in Trieste, Italy, producing photons from the VUV to the soft X-rays with a high degree of coherence and spectral stability. Both FEL lines, FEL-1 and FEL-2, are available for users, down to the shortest wavelength of 4 nm. We report on the completion of the commissioning of the high energy FEL line, FEL-2, on the most recent progress obtained on FEL-1 and on the operational experience for users, in particular those requiring specific FEL configurations, such as two-colour experiments. We will also give a perspective on the improvements and upgrades which have been triggered based on our experience, aiming to maintain as well as to constantly improve the performance of the facility for our user community.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOP034	Beam Optics Measurements at FERMI by using Wire-Scanner	101
	G. Penco, A. Abrami, I. Cudin, S. Di Mitri, M. Ferianis, E. Ferrari, G. Gaio, L. Giannessi, S. Grulja, R. Sauro, L. Sturari Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy E. Ferrari Università degli Studi di Trieste, Trieste, Italy L. Giannessi ENEA C.R. Frascati, Frascati (Roma), Italy G.L. Orlandi, C. Ozkan Loch PSI, Villigen PSI, Switzerland
	Measuring and controlling the electron beam optics is an important ingredient to guarantee high performance of a free-electron laser. In the FERMI linac, the Twiss parameters and the transverse emittances are routinely measured by detecting the beam spot size as a function of a scanning quadrupole placed upstream (i.e. quadrupole scan method). The beam spot size is usually measured with an OTR screen that unfortunately suffers from coherent optical transition radiation (C-OTR) that introduces spurious light and corrupts the image. Moreover, the beam size at the end of the FERMI linac is focused to a few tens of microns and this makes it difficult to precisely measure it with the OTR system, which has an estimated resolution of 20um. For this reason, a wire-scanner system has been installed at the end of the linac just in the waist of the optics channel. The wire-scanner is a SwissFEL prototype installed in FERMI in order to study the hardware and beam loss monitor performances at the GeV energy scale. The beam optics measurements performed with the wire-scanner is here presented, and the obtained results are more in agreement with the theoretical expectations. A more reliable beam optics estimation at the end of the linac has allowed to better match it to the nominal lattice and transport it up to the undulator chain, providing important benefits to the FEL performance.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUB01	Spectro-Temporal Control and Characterization of XUV Pulses from a Seeded Free-Electron Laser
	D. Gauthier, E. Allaria, P. Cinquegrana, M.B. Danailov, G. De Ninno, A.A. Demidovich, E. Ferrari, L. Giannessi, G. Penco, P. Rebernik Ribič, P. Sigalotti Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy G. De Ninno University of Nova Gorica, Nova Gorica, Slovenia E. Ferrari Università degli Studi di Trieste, Trieste, Italy L. Giannessi ENEA C.R. Frascati, Frascati (Roma), Italy B. Mahieu LOA, Palaiseau, France
	In ultrafast X-ray science, the knowledge of and the ability to control the spectro-temporal properties of individual X-ray pulses, such as those from free-electron lasers (FELs), constitute a fundamental aspect in the design of new experiments aimed at probing matter with femtosecond temporal resolution. Recent works carried out at the seeded free-electron laser FERMI in Trieste demonstrate that such a device is able to generate light pulses in the XUV spectral region, whose spectro-temporal content can be precisely controlled. These examples rely on the manipulation of the seed laser used as coherent input signal to drive the FEL process. The first experiment demonstrates the phase control of the FEL output pulse through the manipulation of the seed laser frequency chirp. The second is the implementation of a single-shot method for complete pulse characterization. These experiments show not only the first direct evidence of the temporal coherence and the generation of Fourier limited pulses, but they demonstrate the ability to control and shape the spectro-temporal content of the pulses. Consequently, a seeded FEL can be really considered as a laser-like source providing high peak power light pulses. A fine tuning of the light pulses opens the door to new kinds of experiments in the field of coherent nonlinear optics and coherent quantum control.
	Slides TUB01 [4.430 MB]
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUB04	Influence of a Non-Uniform Longitudinal Heating on High Brightness Electron Beams for FEL
	E. Ferrari Università degli Studi di Trieste, Trieste, Italy E. Allaria, M.B. Danailov, G. De Ninno, S. Di Mitri, D. Gauthier, L. Giannessi, G. Penco, E. Roussel, M. Veronese Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy G. De Ninno, D. Gauthier University of Nova Gorica, Nova Gorica, Slovenia L. Giannessi ENEA C.R. Frascati, Frascati (Roma), Italy
	Laser-heater systems are essential tools to control and optimize high-gain free electron lasers (FELs), working in the x-ray wavelength range. Indeed, these systems induce a controllable heating of the energy spread of the electron bunch. The heating allows in turn to suppress longitudinal microbunching instabilities limiting the FEL performance. In this communication, we show that a long-wavelength energy modulation of the electron beam induced by the laser heater can be preserved until the beam entrance in the undulators, affecting the FEL emission process. This non-uniform longitudinal heating can be exploited to investigate the electron- beam microbunching in the linac, as well as to control the FEL spectral properties. Here, we present experimental, analytical and numerical studies carried out at FERMI.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)