The successful operation of the SPARC injector in the Velocity Bunching (VB) mode has opened new perspectives to conduct advanced beam dynamics experiments with ultra-shor t electron pulses able to extend the THz spectrum or to drive the FEL in the SASE Single Spike mode. Moreover a new technique called Laser Comb, able to generate a train of short pulses with high repetition rate, has been recently tested in the VB configuration. Up to four electron beam pulses shorter than 300 fs and separated by less than 1 ps have been characterized. In addition two electron beam pulses have been injected in the undu lator and a characteristic interference spectrum produced by the FEL interaction in this new configuration has been observed, confirming that both pulses have been correctly matched to the undulator and were both lasing. In this paper we report the experimental results obtained so far.
ADVANCED BEAM DYNAMICS EXPERIMENTS AT SPARC / Bacci, A.; Alesini, D.; Bellaveglia, M.; Castellano, M.; Chiadroni, E.; Cianchi, A.; Del Franco, M.; Di Pirro, G.; Drago, A.; Ferrario, Massimo; Gallo, A.; Gatti, G.; Ghigo, A.; Giannessi, L.; Lupi, Stefano; Marchetti, B.; Mostacci, Andrea; Pace, E.; Palumbo, Luigi; Petralia, A.; Petrillo, V.; Quattromini, M.; Ronsivalle, C.; Rossi, A. R.; Serafini, L.; Serluca, M.; Surrenti, V.; Vaccarezza, Cristina. - ELETTRONICO. - (2011), pp. 451-454. (Intervento presentato al convegno 33rd International Free Electron Laser Conference FEL 2011 tenutosi a Shanghai, China nel August 22 to August 26, 2011.).