INFN/LNF, Frascati (Roma)
UCLA, Los Angeles, California
Istituto Nazionale di Fisica Nucleare, Milano
INFN-Roma II, Roma
ENEA C.R. Frascati, Frascati (Roma)
University of Tehran, Tehran
INFN-Roma, Roma
One of the main goals of the SPARC high brightness photoinjector is the experimental demonstration of the emittance compensation process while compressing the beam with the velocity bunching technique, also named RF compressor. For this reason, the first two S-band travelling wave accelerating structures downstream of the RF gun are embedded in a long solenoid, in order to control the space charge induced emittace oscillations during the compression process. An RF deflecting cavity placed at the exit of the third accelerating structure allows bunch length measurements with a resolution of 50 μm. During the current SPARC run a parametric experimental study of the velocity bunching technique has been performed. The beam bunch length and projected emittance have been measured at 120 MeV as a function of the injection phase in the first linac, and for different solenoid field values. In this paper we describe the experimental layout and the results obtained thus far. Comparisons with simulations are also reported.
INFN/LNF, Frascati (Roma)
Istituto Nazionale di Fisica Nucleare, Milano
INFN-Pisa, Pisa
UNIPI, Pisa
CNR/IPP, Pisa
INFN-Cagliari, Monserrato (Cagliari)
The PLASMONX project foresees the installation at LNF of a 0.2 PW (6 J, 30 fs pulse) Ti:Sa laser system FLAME (Frascati Laser for Acceleration and Multidisciplinary Experiments) to operate in close connection with the existent SPARC electron photo-injector, allowing for advanced laser/e-beam interaction experiments. Among the foreseen scientific activities, a Thomson scattering experiment between the SPARC electron bunch and the high power laser will be performed and a new dedicated beamline is foreseen for such experiments. The beam lines transporting the beam to the interaction chamber with the laser have been designed, and the IP region geometry has been fixed. The electron final focusing system, featuring a quadrupole triplet and large radius solenoid magnet (ensuring an e-beam waist of {10}-15 microns) as well as the whole interaction chamber layout have been defined. The optical transfer line issues: transport up to the interaction, tight focusing, diagnostics, fine positioning, have been solved within the final design. The building hosting the laser has been completed; delivering and installation of the laser,as beam lines elements are now being completed.
INFN/LNF, Frascati (Roma)
Istituto Nazionale di Fisica Nucleare, Milano
CEA, Gif-sur-Yvette
INFN-Roma II, Roma
ENEA C.R. Frascati, Frascati (Roma)
SOLEIL, Gif-sur-Yvette
INFN-Roma, Roma
University of Tehran, Tehran
UCLA, Los Angeles, California
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 SASE, Seeding and Single Spike configurations. The SPARC photoinjector is also the test facility for the recently approved VUV FEL project named SPARX. 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 , the demonstration of the “velocity bunching” technique in the linac and the characterisation of the spontaneous and stimulated radiation in the SPARC undulators. In this paper we report the experimental results obtained so far. The possible future energy upgrade of the SPARC facility to produce UV radiation and its possible applications will also be discussed.
INFN/LNF, Frascati (Roma)
Università di Roma I La Sapienza, Roma
INFN-Roma II, Roma
ELETTRA, Basovizza
Universita' degli Studi di Milano, Milano
Istituto Nazionale di Fisica Nucleare, Milano
A feasibility study for a dedicated beamline for a THz radiation source at SPARC is discussed. A radiofrequency electron gun followed by a compressor can generate trains of THz sub-picosecond electron pulses by illuminating the photocathode with a comb laser pulse. This structure of the beam can be used to produce coherent radiation. The quality of the coherent spectrum emitted by a comb beam is tightly connected to the electron micro-bunches lengths and to micro-pulses inter-distance. Beam dynamics studies are summarized here and compared to a conventional single bunch case, optimized for the THz radiation generation. The dynamics is studied within the SPARC system with the PARMELA code and with the RETAR code for the evaluation of the radiation.
Universita' degli Studi di Milano, Milano
Istituto Nazionale di Fisica Nucleare, Milano
INFN/LNF, Frascati (Roma)
ENEA C.R. Frascati, Frascati (Roma)
INFN-Roma, Roma
In this paper a possible experiment with the existing SPARC photoinjector is described to generate sub-picosecond high brightness electron bunches able to produce single spike radiation pulses at 500 nm with the SPARC self-amplified spontaneous emission free-electron laser (SASE-FEL). The main purpose of the experiment will be the production of short electron bunches as long as few SASE cooperation lengths, the determination of the shape of the radiation pulse and the validation of the single spike scaling law, in order to foresee operation at shorter wavelength in the future operation with SPARX. We present in this paper start to end simulations regarding the beam production and FEL performance, and discuss the layout of the machine. The experience, gained from this experiment, will help in the configuration of the VUV and X-ray FEL SPARX to obtain FEL pulses below 10 fs.