| Paper | Title | Page |
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| MOPPH030 | X-Rays Generation with a FEL Based on an Optical Wiggler | 99 |
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The interaction between high-brilliance electron beams and counter-propagating laser pulses produces X rays via Thomson back-scattering. If the laser source is long and intense enough, the electron beam can bunch on the scale of the X-ray wavelength and a regime of collective effects can establish. In this case the FEL instability can develop and the system behaves like a FEL based on an optical undulator. Coherent X-rays can be irradiated, with a bandwidth thinner than that of the corresponding incoherent emission. The emittance of the electron beam and the non-uniformity of the laser energy limit the growth of the X-ray signal. We analyse with a 3-D code the transverse effects in the emission. The scalings typical of the optical wiggler make possible considerable emission also in violation of the Pellegrini criterion for static wigglers. A generalized form of this criterion is validated on the basis of the numerical evidence. An optimization of the radiation intensity has been done shifting the focus of the beam. The dependence of the radiation on the stability of the laser pulse has been studied.
INFN, Section of MIlan, Via Celoria,16 20133 Milano (Italy) |
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| THAAU06 | Parametric Optimization of a X-Ray FEL Based on a Thomson Source | 517 |
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| We present a study based on a parametric optimization for a Thomson Source operated in FEL mode. This deals with the proposed scheme to use a high energy laser pulse colliding with a high brightness electron beam of low to medium energy electrons undulating in the incoming laser field may emit in a FEL coherent mode as far as some conditions are satisfied. A set of simple analytical formulas taking into account 3D effects is derived to express these conditions in terms of three free parameters, namely the wavelength of the laser, the amplitude of the ripples in the laser field, and the peak current of the eletron beam. A few examples of possible operating points are compared with results of 3D numerical simulations, showing the FEL coherent emission of X-rays in the 0.1 to 5 nm range with tens of MeV high brightness electron beams coliding with high energy laser pulses. | ||
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| THPPH031 | Commissioning of the SPARC Photo-Injector | 637 |
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| The SPARC project is born to perform R&D activity headed to realize SASE-FEL experiments at 500nm and higher harmonic generation. The project foresees the realization of a high brightness photo-injector able to produce a 150-200MeV electron beam to drive FEL process inside a dedicated 14m long undulator. The machine is going to be assembled at LNF and its final configuration is made up of an RF gun, driven by a Ti:Sa laser, injecting into three SLAC type accelerating sections. Nowadays we are working in a photo-injector test phase, aiming to characterize the main hardware components and to investigate the behavior of the e-beam dynamics in the first meters of drift. To do this we utilize the emittance-meter, a home designed diagnostic device placed just after the RF gun, able to move 1.2 meters along the longitudinal axis to measure beam parameters. In this paper we report a more accurate description of the project, the status of the single systems constituting the machine and the most important results we obtained in the e-meter phase. |