Paper | Title | Page |
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WEOB3 |
Seeding Experiments at SPARC | |
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The SPARC FEL amplifier has been configured as a single stage HGHG FEL with a modulator and a radiator operating at the second harmonic. The HGHG cascade has been seeded with harmonics generated in a gas cell where a Ti:Sa laser pulse of 120 fs of duration is converted into higher harmonics. The cascaded FEL configuration obtained by tuning the undulator gaps has been studied by varying the number of modulators and radiators to optimize the conversion efficiency. The process of harmonic generation in a free electron laser operating in superradiant regime has been also analysed. Harmonic generation is expected to be efficient because of the quasi steady-state distribution of the e-beam phase space predicted in this regime. Harmonics up to the 11th have been experimentally observed. | ||
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Slides WEOB3 [5.198 MB] | |
THOB2 | Advanced Beam Dynamics Experiments at SPARC | 451 |
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The successful operation of the SPARC injector in the Velocity Bunching (VB) mode (bunches with 1 kA current with emittance of 3 mm-mrad have been produced) has opened new perspectives to conduct advanced beam dynamics experiments with ultra-short electron pulses able to extend the THz spectrum or to drive the FEL in the SASE Single Spike mode. A new technique called Laser Comb, able to generate a train of short pulses with high repetition rate, has been extensively tested in the VB configuration. Two electron beam pulses 300 fs long separated by 1 ps have been characterized and the spectrum produced by the SASE interaction has been observed, showing that both pulses have been correctly matched to the undulator and were both lasing. In this paper we report the experimental and theoretical results obtained so far. | ||
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Slides THOB2 [6.673 MB] | |