| Paper |
Title |
Page |
| MOPPH058 |
Start-to-end Time-Dependent Study of FEL Output Sensitivity to Electron-beam Jitters for the First Stage of the FERMI@Elettra Project
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178 |
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- G. De Ninno, E. Allaria, M. Trovo
ELETTRA, Basovizza, Trieste
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Sensitivity of the output laser pulse to electron-beam jitters is one of the major issues affecting the expected performance of both SASE and seeded FEL's. Focusing on the first stage of the FERMI@Elettra project, in this paper we present results of time-dependent numerical simulations in which the codes GENESIS and GINGER have been used to process a large number of electron-beam distributions generated at the gun using the code GPT and propagated through the linac using the code ELEGANT.
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| TUPPH021 |
Q-Switch Techniques Implemented at the ELETTRA Storage-Ring Free Electron Laser
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360 |
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- F. Curbis, F. Curbis
Università degli Studi di Trieste, Trieste
- M. B. Danailov, G. De Ninno, B. Diviacco, L. Romanzin, M. Trovo
ELETTRA, Basovizza, Trieste
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In a storage-ring FEL the gain can be calculated measuring the rise-time of giant pulses, produced by the interaction between the light stored in the optical cavity and an electron beam with low energy-spread (cold beam). This interplay produces the heating of the beam. Therefore, after the generation of a single giant pulse, the overlap between electrons and radiation is periodically prevented for a time necessary to dump the energy spread and recover the cold-beam condition. For this purpose two different methods are implemented at Elettra. In the first, modifying the radio-frequency of the ring, the change of the revolution time of electrons avoids the temporal overlap between the electron beam and the optical field in the mirror cavity. The second method relies on a mechanical gating (chopper) which intercept the light produced during previous interactions, inducing a periodic emptying of the optical cavity. The gain can be also estimated using an indirect formula after measuring the electron-beam energy spread and bunch length. In this paper we compare the different techniques mentioned above for the case of the Elettra SR-FEL.
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| MOPPH054 |
FERMI @ Elettra: A Seeded FEL Facility for EUV and Soft X-Rays
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166 |
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- J. N. Corlett, L. R. Doolittle, W. M. Fawley, S. M. Lidia, G. Penn, I. V. Pogorelov, J. Qiang, A. Ratti, J. W. Staples, R. B. Wilcox, A. Zholents
LBNL, Berkeley, California
- E. Allaria, C. J. Bocchetta, D. Bulfone, F. C. Cargnello, D. Cocco, P. Craievich, G. D'Auria, M. B. Danailov, G. De Ninno, S. Di Mitri, B. Diviacco, M. Ferianis, A. Galimberti, A. Gambitta, M. Giannini, F. Iazzourene, E. Karantzoulis, M. Lonza, F. M. Mazzolini, G. Penco, L. Rumiz, S. Spampinati, G. Tromba, M. Trovo, A. Vascotto, M. Veronese, M. Zangrando
ELETTRA, Basovizza, Trieste
- M. Cornacchia, P. Emma, Z. Huang, J. Wu
SLAC, Menlo Park, California
- W. Graves, F. X. Kaertner, D. Wang
MIT, Middleton, Massachusetts
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We describe the conceptual design and major performance parameters for the FERMI FEL project funded for construction at the Sincrotrone Trieste, Italy. This user facility complements the existing storage ring light source at Sincrotrone Trieste, and will be the first facility to be based on seeded harmonic cascade FELs. Seeded FELs provide high peak-power pulses, with controlled temporal duration of the coherent output allowing tailored x-ray output for time-domain explorations with short pulses of 100 fs or less, and high resolution with output bandwidths of the order of meV. The facility uses the existing 1.2 GeV S-band linac, driven by electron beam from a new high-brightness rf photocathode gun, and will provide tunable output over a range from ~100 nm to ~10 nm, and APPLE undulator radiators allow control of x-ray polarization. Initially, two FEL cascades are planned, a single-stage harmonic generation to operate over ~100 nm to ~40 nm, and a two-stage cascade operating from ~40 nm to ~10 nm or shorter wavelengh, each with spatially and temporally coherent output, and peak power in the GW range.
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| THPPH027 |
Ramping Longitudinal Distribution Studies for the FERMI@ELETTRA Injector
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621 |
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- G. Penco, M. Trovo
ELETTRA, Basovizza, Trieste
- S. M. Lidia
LBNL, Berkeley, California
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In the Fermi Linac optimization studies it comes out the request to have at the exit of the photoinjector a linear ramp in the current distribution along the bunch as alternative option with respect to the flat-top. This requirement is translated in the photoinjector optimization in a big issue. In fact the longitudinal bunch profile at the exit of the photoinjector is affected by the strong non linearity of the space charge fields at the cathode and in the drift between the gun and the first booster. The knowledge of the space charge fields at the cathode plays in important role in finding the optimum driven laser pulse shape. At this purpose an analytical description of the space charge fields produced by a bunch with an arbitrary current distribution at the cathode is provided. Space charge codes (GPT and ASTRA) have been used to evaluate the evolution of several ramping profiles from the cathode to the entrance of the first booster and the results are presented in this paper.
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| THPPH028 |
Further Studies in the FERMI@ELETTRA Photoninjector Optimization
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625 |
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- M. Trovo, G. Penco
ELETTRA, Basovizza, Trieste
- S. M. Lidia
LBNL, Berkeley, California
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In the framework of the FERMI@ELETTRA project we are presently studying an electron beam configuration satisfying the bunch energy requirements coming out from the FEL photon production system. The multi-particles tracking code results concerning the photoinjector set up which includes the RF gun and the first two accelerating sections are presented in this paper, describing two possible electron bunch configurations, which satisfy the FEL operation modes. Both injector configurations aim to match the linac requirements to have a ramped current profile at the exit of the photoinjector. Moreover sensitivity studies, time and energy jitters estimations are presented for both cases.
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| TUPPH044 |
Free Electron Laser Study of Free Carbon Clusters
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423 |
| |
- C. Spezzani, E. Allaria, F. Curbis, G. De Ninno, B. Diviacco, L. Romanzin, S. Tileva, M. Trovo
ELETTRA, Basovizza, Trieste
- M. Amati, G. Bongiorno, C. Lenardi, T. Mazza, P. Milani, T. A. Mostefaoui, P. Piseri, L. Ravagnan
Università degli Studi di Milano, Milano
- M. Coreno
CNR - IMIP, Trieste
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UV absorption from carbon nanoparticles is a very interesting astrophysical topic. The prominent hump centered at 217.5nm is the most dominant feature in the interstellar extinction curve and also the most controversial and a long-standing problem in astrophysics. Actual models lack of experimental data about carbon dust in gas phase. At the University of Milano an experimental set-up based on a PulsedμPlasma Source has been developed for the investigation of free clusters at the Elettra Gas Phase beamline (CESyRA: Cluster Experiments with Synctrotron RAdiation). The cluster source produces very intense cluster beams with tunable size distribution. The design of the apparatus is extended with a chamber for gas phase reaction (water vapor, CO, H2…) providing a unique opportunity to study the gas phase properties of carbonaceous particles in different environment. We plan to investigate Resonant Raman scattering of free carbon particles tuning the high brilliance UV/VIS storage ring FEL of ELETTRA across the region of 217nm where the UV absorption hump in astrophysical data is observed and where a number of electronic transitions exist for variable size linear carbon chains.
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