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A. Marinelli

First Name: Agostino

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Last Name: Marinelli

Full Name: A. Marinelli

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18 papers
title: HIGH EFFICIENCY, HIGH BRIGHTNESS X-RAY FREE ELECTRON LASERS VIA FRESH BUNCH SELF-SEEDING
format: conference proceeding
conference: IPAC 2016
year: 2016
6 authors: C. Emma | C. Pellegrini | A. Lutman | M. Guetg | A. Marinelli | J. Wu
abstract: High efficiency, terawatt peak power X-ray Free Electron Lasers (XFELs) are a promising tool for enabling 3D atomic resolution single molecule imaging and nonlinear science using X-ray beams. Increasing the efficiency of XFELs while maintaining good longitudinal coherence can be achieved via self-seeding and tapering the undulator magnetic field. The efficiency of tapered self seeded XFELs is limited by two factors: the ratio of seed power to beam energy spread and the ratio of seed power to electron beam shot noise. We present a method to overcome these limitations by producing a strong X-ray seed and amplifying it with a small energy spread electron bunch. This can be achieved by selectively suppressing lasing for part of the electron beam in the SASE section and using the rest of the bunch to generate the seed radiation. In this manner one can reach saturation with the seeding electrons and the strong seed pulse can be overlapped with the “fresh" electrons downstream of the self-seeding monochromator. Simulations of this scenario demonstrating an increased efficiency are presented for two systems, an optimal superconducting undulator design and the Linac Coherent Light Source. In the case of the LCLS we examine how the betatron oscillations leading to selective suppression can be induced by using the transverse wakefield of a parallel plate corrugated structure, a dechirper.
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title: FEMTOSECOND X-RAY PULSE GENERATION WITH AN ENERGY CHIRPED ELECTRON BEAM
format: conference proceeding
conference: FEL 2015 37th
year: 2015
7 authors: C. Emma | C. Pellegrini | Y. Ding | G. Marcus | A. Lutman | Z. Huang | A. Marinelli
abstract: We study the generation of short (sub 10 fs) pulses in the X-ray spectral region using an energy chirped electron beam in a Self Amplified Spontaneous Emission Free Electron Laser (SASE FEL) and a self-seeding monochromator [1-4]. The monochromator filters a small bandwidth, short duration pulse from the frequency chirped SASE spectrum. This pulse is used to seed a small fraction of the long chirped beam, hence a short pulse with narrow bandwidth is amplified in the following undulators. We present start-to-end simulation results for LCLS operating in the soft X-ray self-seeded mode with an energy chirp of 1% over 30 fs and a bunch charge of 150 pC. We show the possibility to generate 5 fs pulses with a bandwidth 0.3 eV. We also assess the possibility of further shortening the pulse by utilizing one more chicane after the self-seeding stage and shifting the radiation pulse to a “fresh” part of the electron beam. Experimental study on this short pulse seeding mode has been planned at the LCLS.
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title: Single-Shot Coherent Diffraction Imaging of Microbunched Relativistic Electron Beams for Free-Electron Laser Applications
format: journal article
publisher: Physical Review Letters
year: March 2013
10 authors: A. Marinelli | M. Dunning | S. Weathersby | E. Hemsing | D. Xiang | G. Andonian | F.H. O'Shea | Jianwei Miao | C. Hast | J. B. Rosenzweig
abstract: With the advent of coherent x rays provided by the x-ray free-electron laser (FEL), strong interest has been kindled in sophisticated diffraction imaging techniques. In this Letter, we exploit such techniques for the diagnosis of the density distribution of the intense electron beams typically utilized in an x-ray FEL itself. We have implemented this method by analyzing the far-field coherent transition radiation emitted by an inverse-FEL microbunched electron beam. This analysis utilizes an oversampling phase retrieval method on the transition radiation angular spectrum to reconstruct the transverse spatial distribution of the electron beam. This application of diffraction imaging represents a significant advance in electron beam physics, having critical applications to the diagnosis of high-brightness beams, as well as the collective microbunching instabilities afflicting these systems.
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title: Using the Relativistic Two-Stream Instability for the Generation of Soft-X-Ray Attosecond Radiation Pulses
format: journal article
publisher: Physical Review Letters
year: February 2013
3 authors: A. Marinelli | E. Hemsing | J. B. Rosenzweig
abstract: In this Letter we discuss a novel method for generating ultrashort radiation pulses using a broadband two-stream instability in an intense relativistic electron beam. This method relies on an electron beam having two distinct two-energy bands. The use of this new high brightness electron beam scenario, in combination with ultrashort soft x-ray pulses from high harmonic generation in gas, allows the production of high power attosecond pulses for ultrafast pump and probe experiments.
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title: Generation of Coherent Broadband Photon Pulses with a Cascaded Longitudinal Space-Charge Amplifier
format: journal article
publisher: Physical Review Letters
year: 2013
9 authors: A. Marinelli | E. Hemsing | M. Dunning | D. Xiang | S. Weathersby | F. O'Shea | I. Gadjev | C. Hast | J.B. Rosenzweig
abstract: The longitudinal space-charge amplifier has been recently proposed by Schneidmiller and Yurkov as an alternative to the free-electron laser instability for the generation of intense broadband radiation pulses [Phys. Rev. ST Accel. Beams 13, 110701 (2010)]. In this Letter, we report on the experimental demonstration of a cascaded longitudinal space-charge amplifier at optical wavelengths. Although seeded by electron beam shot noise, the strong compression of the electron beam along the three amplification stages leads to emission of coherent undulator radiation pulses exhibiting a single spectral spike and a single transverse mode. The on-axis gain is estimated to exceed 4 orders of magnitude with respect to spontaneous emission.
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title: Coherent optical vortices from relativistic electron beams
format: journal article
publisher: Nature Physics
year: 2013
7 authors: E. Hemsing | A. Knyazik | M. Dunning | D. Xiang | A. Marinelli | C. Hast | J.B. Rosenzweig
abstract: Recent advances in the production and control of high-brightness electron beams (e-beams) have enabled a new class of intense light sources based on the free electron laser (FEL) that can examine matter at ångstrom length and femtosecond time scales. The free, or unbound, electrons act as the lasing medium, which provides unique opportunities to exquisitely control the spatial and temporal structure of the emitted light through precision manipulation of the electron distribution. We present an experimental demonstration of light with orbital angular momentum (OAM; ref.) generated from a relativistic e-beam rearranged into an optical scale helix by a laser. With this technique, we show that a Gaussian laser mode can be effectively up-converted to an OAM mode in an FEL using only the e-beam as a mode-converter. Results confirm theoretical predictions and pave the way for the production of coherent OAM light with unprecedented brightness down to hard X-ray wavelengths for wide ranging applications in modern light sources.
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title: Three dimensional analysis of longitudinal plasma oscillations in a thermal relativistic electron beam: Application to an initial value problem
format: journal article
publisher: Physics of Plasmas
year: 2012
3 authors: A. Marinelli | E. Hemsing | J.B. Rosenzweig
abstract: In this paper, we study the initial value problem of longitudinal plasma oscillations in a relativistic electron beam. Our analysis is based on the formalism developed in Marinelli et al. [Phys. Plasmas 18, 103105 (2011)]. We study the evolution of an arbitrary six-dimensional phase-space perturbation under the effect of longitudinal space-charge forces, with the inclusion of three-dimensional effects due to the finite size of the beam, transverse betatron motion, and longitudinal thermal motion induced by both energy-spread and transverse emittance. We expand the phase-space perturbation in a series of eigenmodes of a Schrödinger-like equation, corresponding to a set of propagating space-charge waves. We develop a general formalism, which we use to find explicit expressions for the evolution of an initial perturbation coupled to the fundamental plasma eigenmode. This work has important applications in the theory of space-charge instabilities in high brightness electron beams and control of shot-noise in seeded free-electron lasers. We discuss the application of the present theory to a specific experimental scenario corresponding to a shot-noise suppression scheme at optical wavelengths.
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title: Experimental observation of helical microbunching of a relativistic electron beam
format: journal article
publisher: Applied Physics Letters
year: 2012
8 authors: E. Hemsing | A. Knyazik | F. O'Shea | A. Marinelli | P. Musumeci | O. Williams | S. Tochitsky | J.B. Rosenzweig
abstract: Experimental observation of the microbunching of a relativistic electron beam at the second harmonic interaction frequency of a helical undulator is presented. The microbunching signal is observed from the coherent transition radiation of the electron beam and indicates experimental evidence of a dominantly helical electron beam density distribution. This result is in agreement with theoretical and numerical predictions and provides a proof-of-principle demonstration of proposed schemes designed to generate light with orbital angular momentum in high-gain free-electron lasers.
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title: Echo-Enabled X-Ray Vortex Generation
format: journal article
publisher: Physical Review Letters
year: 2012
2 authors: E. Hemsing | A. Marinelli
abstract: A technique to generate high-brightness electromagnetic vortices with tunable topological charge at extreme ultraviolet and x-ray wavelengths is described. Based on a modified version of echo-enabled harmonic generation for free-electron lasers, the technique uses two lasers and two chicanes to produce high-harmonic microbunching of a relativistic electron beam with a corkscrew distribution that matches the instantaneous helical phase structure of the x-ray vortex. The strongly correlated electron distribution emerges from an efficient three-dimensional recoherence effect in the echo-enabled harmonic generation transport line and can emit fully coherent vortices in a downstream radiator for access to new research in x-ray science.
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title: Nonlinear Longitudinal Space Charge Oscillations in Relativistic Electron Beams
format: journal article
publisher: Physical Review Letters
year: 6 May 2011
3 authors: P. Musumeci | R.K. Li | A. Marinelli
abstract: In this Letter we study the evolution of an initial periodic modulation in the temporal profile of a relativistic electron beam under the effect of longitudinal space-charge forces. Linear theory predicts a periodic exchange of the modulation between the density and the energy profiles at the beam plasma frequency. For large enough initial modulations, wave breaking occurs after 1=2 period of plasma oscillation leading to the formation of short current spikes. We confirm this effect by direct measurements on a ps-modulated electron beam from an rf photoinjector. These results are useful for the generation of intense electron pulse trains for advanced accelerator applications.
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title: Harmonic radiation of a relativistic nonlinear inverse Compton scattering using two laser wavelengths
format: journal article
publisher:
year: 2011
9 authors: Y. Sakai | O. Williams | G. Andonian | A. Fukasawa | E. Hemsing | A. Marinelli | S. Barber | F.H. O'Shea | J.B. Rosenzweig
abstract: The use of two different wavelength lasers in the nonlinear regime of the inverse Compton scattering interaction is proposed in order to provide a new strategy for controlling scattered photon energy distributions in the x-ray to γ-ray spectral region. In this nonlinear interaction, the component of the relativistic electron’s trajectory driven by a longer-wavelength laser with the normalized vector potential aL∼1 is a large oscillatory figure-8; in the proposed scenario a rapid small-amplitude oscillation induced by a shorter-wavelength laser is superimposed upon this figure-8. Thus, the electron’s momentum is mainly supplied from longer-wavelength laser, while the high-frequency part of the acceleration is given by shorter-wavelength laser. In this way, the harmonics radiated at high frequency from the oscillating electron can be strongly modified by the nonlinear motion initiated by the low frequency, large aL laser resulting in the generation of the harmonics with the photon energy of 4γ2h̵(ωL,short+nωL,long). In this paper, the electron’s kinetics in the two-wavelength laser field and the concomitant emitted radiation spectrum are examined, with numerical illustrations based on a classical Lienard-Wiechert potential formalism provided.
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title: Three dimensional analysis of longitudinal plasma oscillations in a thermal relativistic electron beam
format: journal article
publisher: Physics of Plasmas
year: 2011
3 authors: A. Marinelli | E. Hemsing | J.B. Rosenzweig
abstract: In this paper, we develop a three-dimensional kinetic theory of longitudinal plasma oscillations in a relativistic electron beam. Our analysis includes the effects of betatronmotion, finite emittance, and energy spread as well as edge effects due to the finite size of the beam. The consequences of these effects are shown to be of significant interest, as they give rise to several distinct new phenomena. These include an emittance induced anisotropy between backward and forward propagating plasma waves as well as a beatwave effect between plasma and betatronoscillations caused by the coupling of betatronmotion to the transverse structure of the charge perturbation. The experimental implications of these new results and their relevance to the beam and radiation physics of advanced light sources, such as free-electron lasers, are also discussed.
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title: Generating Optical Orbital Angular Momentum in a High-Gain Free-Electron Laser at the First Harmonic
format: journal article
publisher: Physical Review Letters
year: 22 April 2011
3 authors: E. Hemsing | A. Marinelli | J.B. Rosenzweig
abstract: A scheme to generate intense coherent light that carries orbital angular momentum (OAM) at the fundamental wavelength of an x-ray free-electron laser (FEL) is described. The OAM light is emitted as the dominant mode of the system until saturation provided that the helical microbunching imposed on the electron beam is larger than the shot-noise bunching that leads to self-amplified emission. Operating at the fundamental, this scheme is more efficient than alternate schemes that rely on harmonic emission, and can be applied to x-ray FELs without using external optical mode conversion elements.
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title: Breaking the Attosecond, Angstrom and TV/m Field Barriers with Ultrafast Electron Beams
format: conference proceeding
conference: AAC 2010 14th
year: 2010
17 authors: J.B. Rosenzweig | G. Andonian | P. Bucksbaum | A. Fukasawa | M. Ferrario | M. Hogan | E. Hemsing | P. Krejcik | G. Marcus | A. Marinelli | P. Muggli | P. Musumeci | B. O'Shea | F. O'Shea | C. Pellegrini | D. Schiller | G. Travish
abstract: Recent initiatives at UCLA concerning ultra-short, GeV electron beam generation have been aimed at achieving sub-fs pulses capable of driving X-ray free-electron lasers (FELs) in single-spike mode. This scheme uses very low charge beams, which may allow existing FEL injectors to produce few-100 attosecond pulses, with very high brightness. Towards this end, recent experiments at the Stanford X-ray FEL (LCLS, first of its kind, built with essential UCLA leadership) have produced ~2 fs, 20 pC electron pulses. We discuss here extensions of this work, in which we seek to exploit the beam brightness in FELs, in tandem with new developments at UCLA in cryogenic undulator technology, to create compact accelerator/undulator systems that can lase below 0.15 Å, or be used to permit 1.5 Å operation at 4.5 GeV. In addition, we are now developing experiments which use the present LCLS fs pulses to excite plasma wakefields exceeding 1 TV/m, permitting a table-top TeV accelerator for frontier high energy physics applications. We discuss the experimental issues associated with this initiative.
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title: Helical Electron-Beam Microbunching by Harmonic Coupling in a Helical Undulator
format: journal article
publisher: PRL
year: April 29, 2009
7 authors: E. Hemsing | P. Musumeci | S. Reiche | R. Tikhoplav | Agostino Marinelli | J.B. Rosenzweig | A. Gover
abstract: Microbunching of a relativistic electron beam into a helix is examined analytically and in simulation. Helical microbunching is shown to occur naturally when an e beam interacts resonantly at the harmonics of the combined field of a helical magnetic undulator and an axisymmetric input laser beam. This type of interaction is proposed as a method to generate a strongly prebunched e beam for coherent emission of light with orbital angular momentum at virtually any wavelength. The results from the linear microbunching theory show excellent agreement with three-dimensional numerical simulations.
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title: Longitudinal dispersion of orbital angular momentum modes in high-gain free-electron lasers
format: journal article
publisher: APS
year: July 30, 2008
4 authors: E. Hemsing | Agostino Marinelli | Sven Reiche | J.B. Rosenzweig
abstract: The physical effects of optical mode dispersion in the electron beam of a free-electron laser are investigated for modes that carry orbital angular momentum. The analysis is performed using a derived equivalence between two different formulations that describe the radiation fields in the linear regime.
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title: Recent results and future perspectives of the SPARC project
format: conference proceeding
conference: EPAC 2008
year: 2008
77 authors: M. Ferrario | D. Alesini | M. Bellaveglia | R. Boni | M. Boscolo | M. Castellano | E. Chiadroni | A. Clozza | L. Cultrera | G. Di Pirro | A. Drago | A. Esposito | L. Ficcadenti | D. Filippetto | V. Fusco | A. Gallo | G. Gatti | A. Ghigo | B. Marchetti | Agostino Marinelli | C. Marrelli | M. Migliorati | A. Mostacci | E. Pace | L. Palumbo | L. Pellegrino | R. Ricci | U. Rotundo | C. Sanelli | F. Sgamma | B. Spataro | F. Tazzioli | S. Tomassini | C. Vaccarezza | M. Vescovi | C. Vicario | F. Ciocci | G. Dattoli | A. Dipace | a. Doria | G. P. Gallerano | L. Giannessi | E. Giovenale | G. Orlandi | S. Pagnutti | A. Petraia | M. Quattromini | C. Ronsivalle | E. Sabia | I. Spassovsky | V. Surrenti | L. Catani | A. Cianchi | M. Mattioli | M. Petrarca | M. Serluca | A. Bacci | I. Boscolo | F.Broggi | F. Castelli | S. Cialdi | C. De Martinis | D. Giove | C. Maroli | V. Petrillo | A.R. Rossi | L. Serafini | J.B. Rosenzweig | M. E. Couprie | M. Bougeard | B. Carré | D. Garzella | M. Labat | G. Lambert | H. Merdji | P. Salières | O. Tchebakoff
abstract: The SPARC project foresees the realization of a high brightness photo-injector to produce a 150-200 MeV electron beam to drive 500 nm FEL experiments in various configurations, a Thomson backscattering source and a plasma accelerator experiment (these last two ones jointly with the project PLASMONX). The SPARC photoinjector is also the test facility for the recently approved VUV FEL project named SPARX. As a first stage of the commissioning, a complete characterization of the photoinjector has been accomplished with a detailed study of the emittance compensation process downstream the gun-solenoid system: this lead to the first direct experimental demonstration of emittance oscillations in a drift. The second stage of the commissioning, that is currently underway, foresees a detailed analysis of the beam matching with the linac in order to confirm the theoretically prediction of emittance compensation based on the invariant envelope matching and the demonstration of the velocity bunching technique in the linac. SASE and SEEDING experiments are foreseen by the end of the current year. In this paper we report the experimental results obtained so far and the scientific program for the near future.
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title: Status of the SPARC-X Project
format: conference proceeding
conference: PAC 2007
year: 2007
97 authors: C. Vaccarezza | D. Alesini | M. Bellaveglia | S. Bertolucci | R. Boni | M. Boscolo | M. Castellano | A. Clozza | L. Cultrera | G. Di Pirro | A. Drago | A. Esposito | M. Ferrario | L. Ficcadenti | D. Filippetto | V. Fusco | A. Gallo | G. Gatti | A. Ghigo | C. Ligi | Agostino Marinelli | M. Migliorati | A. Mostacci | E. Pace | L. Palumbo | L. Pellegrino | M. Preger | R. Ricci | C. Sanelli | M. Serio | F. Sgamma | B. Spataro | A. Stella | F. Tazzioli | M. Vescovi | C. Vicario | F. Ciocci | G. Dattoli | A. Dipace | A. Doria | F. Flora | G.P. Gallerano | L. Giannessi | E. Giovenale | G. Messina | P.L. Ottaviani | S. Pagnutti | G. Parisi | L. Picardi | M. Quattromini | A. Renieri | G. Ronci | C. Ronsivalle | M. Rosetti | E. Sabia | M. Sassi | A. Torre | A. Zucchini | M. Mattioli | D. Pelliccia | L. Catani | E. Chiadroni | A. Cianchi | E. Gabrielli | C. Schaerf | P. Musumeci | M. Petrarca | F. Alessandria | A. Bacci | R. Bonifacio | I. Boscolo | F. Broggi | C. De Martinis | F. Castelli | S. Cialdi | D. Giove | A. Flacco | C. Maroli | V. Petrillo | A.R. Rossi | L. Serafini | A. Perrone | M. Labat | O. Tcherbakoff | G. Lambert | D. Garzella | M. Bougeard | P. Breger | P. Monchicourt | H. Merdji | P. Salie?res | B. Carre? | M. E. Couprie | P. Emma | C. Pellegrini | S. Reiche | J.B. Rosenzweig
abstract: SPARC-X is a two branch project consisting in the SPARC test facility dedicated to the development and test of critical subsystems such as high brightness photoinjector and a modular expandable undulator for SASE-FEL experiments at 500 nm with seeding, and the SPARX facility aiming at generation of high brilliance coherent radiation in the 1.5-13 nm range, based on the achieved expertise. The projects are supported by MIUR (Research Department of Italian Government) and Regione Lazio. SPARC has completed the commissioning phase of the photoinjector in November 2006. The achieved experimental results are here summarized together with the status of the second phase commissioning plans. The SPARX project is based on the generation of ultra high peak brightness electron beams at the energy of 1 and 2 GeV generating radiation in the 1.5-13 nm range. The construction is at the moment planned in two steps starting with a 1 GeV Linac. The project layout including both RF-compression and magnetic chicane techniques has been studied.
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