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Title |
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| MOPCH045 |
A Source of Coherent Soft X-ray Radiation Based on High-order Harmonic Generation and Free Electron Lasers
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142 |
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- M. Gullans, J.S. Wurtele
UCB, Berkeley, California
- G. Penn, A. Zholents
LBNL, Berkeley, California
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We examine a scheme for a Free Electron Laser (FEL) harmonic amplifier seeded by a ~30-nm wavelength signal produced using a process of High-order Harmonic Generation (HHG). The seed is first amplified in an optical klystron from ~100 kW to ~30 MW using a 1 GeV electron beam and then is used for an energy modulation of electrons in the downstream undulator. Subsequently, a 100-MW level of radiation at shorter wavelengths down to 4 nm is obtained by bunching the energy modulated electrons and passing the bunched beam through an undulator tuned to the desired harmonic of 30 nm. We also compare this scheme to a more familiar harmonic cascade FEL by replacing the HHG with an additional stage of harmonic generation.
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| MOPCH047 |
Study of the Electron Beam Dynamics in the FERMI @ ELETTRA Linac
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145 |
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- M. Cornacchia, P. Craievich, S. Di Mitri
ELETTRA, Basovizza, Trieste
- I.V. Pogorelov, J. Qiang, M. Venturini, A. Zholents
LBNL, Berkeley, California
- D. Wang
MIT, Middleton, Massachusetts
- R.L. Warnock
SLAC, Menlo Park, California
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A study of the electron beam dynamics in the linac is made within the framework of the design of a free electron laser (FEL) at the Syncrotrone Trieste*. A scope of the work includes analysis of two operational scenarios, one with relatively long electron bunches of the order of 1.5 ps and a moderate peak current of 500 A and one with shorter bunches of the order of 0.7 ps and higher peak current of the order of 800 A. In both cases, care has been taken to preserve the slice and projected emittances formed in the photocathode gun injector and to minimize the slice energy spread. The latter goal is accomplished by balancing the onset of the microbunching instability driven by the longitudinal space charge forces and the emission of coherent synchrotron radiation using Landau damping produced by a so-called laser heater. Various analytical techniques and tracking codes have been employed to obtain the reported results.
*C. Bocchetta, et al., this conference.
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| MOPCH021 |
FERMI @ Elettra: Conceptual Design for a Seeded Harmonic Cascade FEL for EUV and Soft X-rays
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0 |
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- C.J. Bocchetta, E. Allaria, D. Bulfone, P. Craievich, G. D'Auria, M.B. Danailov, G. De Ninno, S. Di Mitri, B. Diviacco, M. Ferianis, A. Gambitta, A. Gomezel, E. Karantzoulis, G. Penco, M. Trovo
ELETTRA, Basovizza, Trieste
- J.N. Corlett, W.M. Fawley, S.M. Lidia, G. Penn, A. Ratti, J.W. Staples, R.B. Wilcox, A. Zholents
LBNL, Berkeley, California
- M. Cornacchia, P. Emma
SLAC, Menlo Park, California
- W. Graves, F.O. Ilday, F.X. Kaertner, D. Wang
MIT, Middleton, Massachusetts
- F. Parmigiani
Università Cattolica-Brescia, Brescia
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We present a summary of the conceptual design for the FERMI FEL project funded for construction at the Sincrotrone Trieste, Italy. The project will be the first user facility based on seeded harmonic cascade FEL's, providing controlled, high peak-power pulses, and complementing the storage ring light source at Sincrotrone Trieste. The facility is to be driven by electron beam from a high-brightness rf photocathode gun, and using the existing 1.2 GeV S-band linac. Designed for an initial complement of two FEL's, providing tunable output over a range from ~100 nm to ~10 nm, FERMI will allow control of pulse duration from less than 100 fs to approximately1 ps, and with polarization control from APPLE undulator radiators. Seeded by tunable UV lasers, FEL-1 is a single-stage of harmonic generation to operate over ~100 nm to ~40 nm, and FEL-2 a two-stage cascade operating from ~40 nm to ~10 nm or shorter wavelength. Photon output is spatially and temporally coherent, with peak power in the 100’s MW to GW range. We have designed FEL-2 to minimize the output radiation spectral bandwidth. Major systems and overal facility layout are described, and key performance parameters summarized.
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| THOPA01 |
Formation of Electron Bunches for Harmonic Cascade X-ray Free Electron Lasers
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2738 |
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- M. Cornacchia, S. Di Mitri, G. Penco
ELETTRA, Basovizza, Trieste
- A. Zholents
LBNL, Berkeley, California
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A relatively long electron bunch is required for an operation of harmonic cascade free electron lasers (FELs). This is because they repeatedly employ a principle when the radiation produced in one cascade by one group of electrons proceeds ahead and interacts with other electrons from the same electron bunch in the next cascade. An optical laser is used to seed the radiation in the first cascade. Understandably the length of the electron bunch in this situation must accommodate the length of the x-ray pulse multiplied by a number of cascades plus a time jitter between the arrival time of the electron bunch and a seed laser pulse. Thus a variation of the peak current along the electron bunch as well as slice energy spread and emittance may affect the performance of the FEL. In this paper we analyze all possible sources affecting the distributions and interplay between them and show how desirable distributions can be produced. Results are illustrated with simulations using particle tracking codes.
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Transparencies
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| THPCH043 |
Jitter Studies for the FERMI@ELETTRA Linac
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2880 |
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- P. Craievich, S. Di Mitri
ELETTRA, Basovizza, Trieste
- A. Zholents
LBNL, Berkeley, California
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The FEL project FERMI@ELETTRA* will use the existing linac upgraded to 1.2GeV to produce photon pulses in the wavelength range between 100-10 nm by means of harmonic generation in a seeded scheme. FEL operations foresee stringent requirements for the stability of the global linac output parameters, such as the electron bunch arrival time, peak current, average energy and the slice electron bunch parameters, such as the slice peak current and slice average energy. In order to understand the sensitivity of these parameters to jitters of various error sources along the linac an elaborate study using tracking codes has been performed. As a result, we created a tolerance budget to be used as guidance in the design of the linac upgrade. In this paper we give a detailed description of the applied procedures and present the obtained results.
*C. Bocchetta et al. "FERMI@ELETTRA - Conceptual Design for a Seeded Harmonic Cascade FEL for EUV and Soft X-rays", this conference.
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