EuPRAXIA@SPARC_LAB is a new multi-disciplinary user-facility that is currently under construction at the Laboratori Nazionali di Frascati of the INFN in the framework of the EuPRAXIA collaboration. The electron beam will be accelerated by an X-band normal conducting linac followed by a Plasma WakeField Acceleration (PWFA) stage. It will be characterized by a small footprint and it will drive two FEL beamlines for experiments, one in the VUV (50 to 180 nm) and the other in the XUV-soft x-rays (4 to 10 nm) spectral region. As an ancillary beamline, we are also including a betatron source in the x-ray from laser-plasma interaction. We present the status update of our facility.
Nanoscale electron pulses are increasingly in demand, including as probes of nanoscale ultrafast dynamics and for emerging light source and lithography applications. Using electromagnetic simulations, we show that gold plasmonic lenses as multiphoton photoemitters provide unique advantages, including emission from an atomically at surface, nanoscale pulse diameter regardless of laser spot size, and femtosecond-scale response time. We then present fabrication of prototypes with sub-nm roughness via e-beam lithography, as well as electro-optical characterization using cathodoluminescence spectromicroscopy. Finally, we introduce a DC photogun at LBNL built for testing ultrafast photoemitters. We discuss measurement considerations for ultrafast nanoemitters and predict that we can extract tens of pA photocurrent from a single plasmonic lens using a Ti:Sa oscillator. Altogether, this lays the groundwork to develop and test a broad class of plasmon-enhanced ultrafast nanoemitters.
The SPARC LAB complex hosts a 150 MeV electron photo-injector equipped with an undulator for FEL production (SPARC) together with a high power TW laser (FLAME). Recently the synchronization system reached the performance of < 100 fsRMS relative jitter between lasers, electron beam and RF accelerating fields. This matches the requirements for next future experiments: (i) the production of X-rays by means of Thomson scattering (first collisions achieved in 2014) and (ii) the particle driven PWFA experiment by means of multiple electron bunches. We report about the measurements taken during the machine operation using BAMs (Bunch Arrival Monitors) and EOS (Electro-Optical Sampling) system. A new R and D activity concerning the LWFA using the external injection of electron bunches in a plasma generated by the FLAME laser pulse is under design. The upgrade of the synchronization system is under way to guarantee the < 30 fs RMS jitter required specification. It foresees the transition from electrical to optical architecture that mainly affects the reference signal distribution and the time of arrival detection performances. The new system architecture is presented together with the related experimental data.
Fabio Villa, David Alesini, Maria Pia Anania, Marcello Artioli, Alberto Bacci, Marco Bellaveglia, Mariano Carpanese, Michele Castellano, Alessandro Cianchi, Franco Ciocci, Enrica Chiadroni, Giuseppe Dattoli, Domenico Di Giovenale, Emanuele Di Palma, Giampiero Di Pirro, Massimo Ferrario, Francesco Filippi, Alessandro Gallo, Giancarlo Gatti, Luca Giannessi, Anna Giribono, Luca Innocenti, Najmeh Sada Mirian, Andrea Mostacci, Alberto Petralia, Vittoria Petrillo, Riccardo Pompili, Julietta Rau, Stefano Romeo, Andrea Renato Rossi, Elio Sabia, Vladimir Shpakov, Ivan Spassovsky, Cristina Vaccarezza
We present the experimental evidence of the generation of coherent and statistically stable Free-Electron Laser (FEL) two color radiation obtained by seeding an electron double peaked beam in time and energy with a single peaked laser pulse. The FEL radiation presents two neat spectral lines, with time delay, frequency separation and relative intensity that can be accurately controlled. The analysis of the emission shows a temporal coherence and regularity in frequency significantly enhanced with respect to the Self Amplified Spontaneous Emission (SASE).
KEYWORDS: Free electron lasers, Magnetism, Electron beams, Physics, Optical simulations, Space operations, Polarization, Harmonic generation, Spectroscopy, Signal generators
A short period undulator (1.4 cm) has been designed for the SPARC-FEL test facility and has been realized in collaboration with KYMA Srl. It has been installed on the undulator line at SPARC. The undulator, operating in a delta like mode, has been used as radiator in a segmented configuration. The first stage being provided by the five undulators of the SPARC FEL source “old” chain, with period 2.8 cm. The KYMA undulator has a quatrefoil structure, a high magnetic field homogeneity and focuses both in vertical and radial directions. The two sections, namely the bunching and radiating parts, are arranged in such a way that the second is adjusted on a harmonic of the first. Laser action occurring in the second part, is due to the bunching acquired in the first. Simulations of the temporal and spectral profiles in different electron beam operating conditions are reported, as well as the evolution of the longitudinal phase space. The agreement with the experimental results is discussed The importance of this experiment is at least threefold: 1) It proves that the segmented undulator can successfully be operated 2) It proves that the laser emission in the last undulator is entirely due to the bunching mechanism, being no second harmonic signal present in the first segment 3) Encourages various improvements of the configuration itself, as e.g. the use of a further undulator with variable magnetic field configuration in order to obtain a laser field with adjustable polarization.
The linac-based Terahertz source at the SPARC_LAB test facility is able to generate highly intense Terahertz broadband pulses via coherent transition radiation (CTR) from high brightness electron beams. The THz pulse duration is typically down to 100 fs RMS and can be tuned through the electron bunch duration and shaping. The measured stored energy in a single THz pulse has reached 40 μJ, which corresponds to a peak electric field of 1.6 MV/cm at the THz focus. Here we present the main features, in particular spatial and spectral distributions and energy characterizations of the SPARC_LAB THz source, which is very competitive for investigations in Condensed Matter, as well as a valid tool for electron beam longitudinal diagnostics.
A. Mostacci, D. Alesini, M. P. Anania, A. Bacci, M. Bellaveglia, A. Biagioni, F. Cardelli, Michele Castellano, Enrica Chiadroni, Alessandro Cianchi, M. Croia, Domenico Di Giovenale, Giampiero Di Pirro, Massimo Ferrario, Francesco Filippi, Alessandro Gallo, Giancarlo Gatti, Anna Giribono, L. Innocenti, A. Marocchino, M. Petrarca, L. Piersanti, S. Pioli, Riccardo Pompili, Stefano Romeo, Andrea Renato Rossi, V. Shpakov, J. Scifo, Cristina Vaccarezza, Fabio Villa, L. Weiwei
Sub-picosecond, high-brightness electron bunch trains are routinely produced at SPARC-LAB via the velocity bunching technique. Such bunch trains can be used to drive multi-color Free Electron Lasers (FELs) and plasma wake field accelerators. In this paper we present recent results at SPARC-LAB on the generation of such beams, highlighting the key points of our scheme. We will discuss also the on-going machine upgrades to allow driving FELs with plasma accelerated beams or with short electron pulses at an increased energy.
To create very short electron bunches or comb-like beams, able to drive a SASE-FEL, to produce THz radiation, or to drive a plasma beam driven accelerator is needed advanced phase space manipulation. The characterization of the 6D phase space is of paramount importance in order to verify that the beam parameters fulfill the expectation. At SPARCLAB we have integrated several longitudinal and transverse beam diagnostics for single bunch or for a train of comb-like bunches at THz repetition rate. Longitudinal diagnostic is based on RF deflecting cavity and a dispersive element. Quadrupole scan technique is used to measure the transverse emittance in single bunch mode or in conjunction respectively with a dipole, to separate beams of different energy, and RF deflector, to discriminates bunches with different time of arrival.
C. Vaccarezza, D. Alesini, M. Bellaveglia, S. Bertolucci, M. Biagini, R. Boni, M. Boscolo, M. Castellano, A. Clozza, L. Cultrera, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, D. Filippetto, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci, M. Migliorati, L. Palumbo, L. Pellegrino, M. Preger, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stella, F. Tazzioli, M. Vescovi, C. Vicario, F. Ciocci, G. Dattoli, A. Doria, F. Flora, G. Gallerano, L. Giannessi, E. Giovenale, G. Messina, P. Ottaviani, G. Parisi, L. Picardi, M. Quattromini, A. Renieri, C. Ronsivalle, S. Cialdi, C. Maroli, V. Petrillo, M. Romè, L. Serafini, L. Catani, E. Chiadroni, A. Cianchi, C. Schaerf, P. Musumeci, F. Alessandria, A. Bacci, F. Broggi, C. De Martinis, D. Giove, M. Mauri, L. Ficcadenti, M. Mattioli, A. Mostacci, P. Emma, S. Reiche, J. Rosenzweig
KEYWORDS: Magnetism, Free electron lasers, Electron beams, Particles, Stanford Linear Collider, Superconductors, Diagnostics, S band, Lanthanum, Energy efficiency
The SPARX project consists in an X-ray-FEL facility jointly supported by MIUR (Research Department of Italian
Government), Regione Lazio, CNR, ENEA, INFN and Rome University Tor Vergata. It is the natural extension of the
ongoing activities of the SPARC collaboration. The aim is the generation of electron beams characterized by ultra-high
peak brightness at the energy of 1 and 2 GeV, for the first and the second phase respectively. The beam is expected to
drive a single pass FEL experiment in the range of 13.5-6 nm and 6-1.5 nm, at 1 GeV and 2 GeV respectively, both in
SASE and SEEDED FEL configurations. A hybrid scheme of RF and magnetic compression will be adopted, based on
the expertise achieved at the SPARC high brightness photoinjector presently under commissioning at Frascati INFNLNF
Laboratories. The use of superconducting and exotic undulator sections will be also exploited. In this paper we
report the progress of the collaboration together with start to end simulation results based on a combined scheme of RF
compression techniques.
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