First Name: G.
Middle Name: Di
Last Name: Pirro
Full Name: G. Di Pirro
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9 papers
| title: | Optinum Beam Creation In Photoinjectors Using Space-Charge Expansion |
| format: | conference procceeding |
| conference: | |
| year: | 2006 |
| 16 authors: | | | | | | | | | | | | | | | | |
| abstract: | It has recently been shown that by illuminating a photocathode with an ultra-short laser pulse of appropriate transverse profile, a uniform density, ellipsoidally shaped bunch is dynamically formed, which then has linear space-charge fields in all dimensions inside of the bunch. We study here this process, and its marriage to the standard emittance compensation scenario that is implemented in most modern photoinjectors. It is seen that the two processes are compatible, with simulations indicating that a very high brightness beam can be obtained. The scheme has produced stimulus for a series of experiments at the SPARC injector at Frascati in 2006-2007. An initial time-resolved experiment has been performed involving Cerenkov radiation produced at an aerogel. We discuss the results of this preliminary experiment, as well as plans for future experiments to resolve the ellipsoidal bunch shape at low energy. Future measurements at high energy based on fs resolution RF sweepers are discussed. |
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| title: | EXPERIMENTAL TESTING OF DYNAMICALLY OPTIMIZED PHOTOELECTRON BEAMS |
| format: | conference procceeding |
| conference: | Erice 2005 |
| year: | 2006 |
| 16 authors: | | | | | | | | | | | | | | | | |
| abstract: | We discuss the design of and initial results from an experiment in space-charge dominated beam dynamics which explores a new regime of high-brightness electron beam generation at the SPARC (located at INFN-LNF, Frascati) photoinjector. The scheme under study employs the natural tendency in intense electron beams to configure themselves to produce a uniform density, giving a nearly ideal beam from the viewpoint of space charge-induced emittance. The experiments are aimed at testing the marriage of this idea with a related concept, emittance compensation, We show that the existing infrastructure at SPARC is nearly ideal for the proposed tests, and that this new regime of operating photoinjector may be the preferred method of obtaining highest brightness beams with lower energy spread. We discuss the design of the experiment, including developing of a novel time-dependent, aerogel-based imaging system. This system has been installed at SPARC, and first evidence for nearly uniformly filled ellipsoidal charge distributions recorded. |
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| title: | The SPARC Project: A High Brightness Electron Beam Source at LNF to Drive a SASE-FEL Experiment |
| format: | conference procceeding |
| conference: | 2003 Particle Accelerator Conference |
| year: | 2003 |
| 75 authors: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| abstract: | The Project SPARC (Sorgente Pulsata e Amplificata di Radiazione Coerente), proposed by a collaboration among ENEA-INFN-CNR-Universita' di Roma "Tor Vergata" -INFM-ST, was recently approved by the Italian Government and will be built at LNF of INFN. The aim of the project is to promote an R&D activity oriented to the development of a coherent ultra-brilliant X-ray source in Italy. This collaboration has identified a program founded on two main issues: the generation of ultra-high peak brightness electron beams and of resonant higher harmonics in the SASE-FEL process. |
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| title: | Recent results and future perspectives of the SPARC project |
| format: | conference procceeding |
| conference: | EPAC 2008 |
| year: | 2008 |
| 77 authors: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| 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. |
| keywords: | pbpl_pub |
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| title: | Status of the SPARC-X Project |
| format: | journal article |
| year: | 2007 |
| 97 authors: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| 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. |
| keywords: | pbpl |
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| title: | OPTIMUM ELECTRON BUNCH CREATION IN A PHOTOINJECTOR |
| format: | journal article |
| year: | 2007 |
| 16 authors: | | | | | | | | | | | | | | | | |
| abstract: | Recent studies have shown that by illuminating a pho- tocathode with an ultra-short laser pulse of appropriate transverse profile, a uniform density, ellipsoidally shaped electron bunch can be dynamically formed. Linear space- charge fields then exist in all dimensions inside of the bunch, which minimizes emittance growth. Here we study this process, and its marriage to the standard emittance compensation scenario that is implemented in most modern photoinjectors. We show that the two processes are com- patible, with simulations indicating that a very high bright- ness beam can be obtained. An initial time-resolved experi- ment has been performed at the SPARC injector in Frascati, involving Cerenkov radiation produced at an aerogel. We discuss the results of this preliminary experiment, as well as plans for future experiments at the UCLA Pegasus labo- ratory to resolve the ellipsoidal bunch shape at low energy. Future measurements at high energy based on fs resolution RF sweepers are discussed. |
| keywords: | pbpl |
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| title: | Status of the SPARC Photoinjector |
| format: | journal article |
| year: | 2006 |
| 69 authors: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| abstract: | The SPARC Project is starting the commissioning of its photo-injector. RF gun, RF sources, RF network and control, power supplies, emittance meter, beam diagnostics and control to measure the RF gun beam have been installed. The photocathode drive laser has been characterized in terms of pulse shape and quality. We will report also about first tests made on RF gun and on the emittance meter device. Additional R&D on X-band and S-band structures for velocity bunching are in progress, as well as studies on new photocathode materials. We will also discuss studies on solenoid field defects, beam based alignments and exotic electron bunch production via blow-out of short laser pulses. |
| keywords: | pbpl |
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| title: | Status Report on SPARC Project |
| format: | journal article |
| year: | |
| 96 authors: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| abstract: | We review the status of FEL source activity of the ongoing SPARC FEL experiment, developed within the framework of a collaboration among ENEA, CNR, INFN, INFM, Sincrotrone Trieste and University of Rome Tor Vergata. The project is aimed at realising a SASE-FEL source, operating in the visible (around 500 nm), with an extended range of tunability down to the VUV (100 nm) by the use of the mechanism of non-linear harmonic generation. The development of the relevant activities foresees the realisation of an advanced 150 MeV photo- injector source, aimed at producing a high brightness electron beams, needed to drive a SASE-FEL experiment, and a 14 m long undulator. We present the status of the design and construction of SPARC FEL device. In particular we discuss the choice of the project parameters, their optimisation and the sensitivity of the SPARC performance to any parameter variation. We will show, using start-to-end simulations, what is the impact of the e- beam and of the undulator parameters on the characteristics of the output laser field and in particular on the amount of the non-linearly generated power at higher harmonics. |
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| title: | RF Measurements results of the final brazed SPARC RF Deflector |
| format: | journal article |
| year: | |
| 7 authors: | | | | | | | |
| abstract: | The longitudinal phase space and the horizontal beam slice emittance measurements of the SPARC 150MeV-lnC electron beam, foresee the use of a RF deflector. he device is a five cells standing wave structure operating on the TM110-like dipole mode at 2.856Ghz and allows reaching a longitudinal resolution of ~12um with 2MW of peak input power. In the paper we illustrate the RF measurements results on the final brazed copper device. |
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