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| PLT33 |
Summary of WG3 – Free Electron Lasers
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- Z. Huang
SLAC, Menlo Park, California
- L. Serafini
INFN-Milano, Milano
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Summary of the Free Electron Lasers Working Group
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Slides
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| WG342 |
Design of the Thomson Source at SPARC/PLASMONX for Incoherent and Coherent X-Rays
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- L. Serafini
INFN-Milano, Milano
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The SPARC Project, presently commissioning its photo-injector, will be upgraded, in the frame of the Project PLASMONX, by installing at LNF an ultra-high intensity Ti:Sa laser system, delivering 30 fs laser pulses, synchronized to the SPARC electron beam, carrying up to 200 TW. The collision of the two beams will produce X-rays by Thomson back-scattering with unprecedented characteristics of: monochromaticity (in the range 1–10 % bandwidth), tunability in the 20–500 keV spectral region, rapidity (from 100 fs to 10 ps pulses) and brilliance, which is comparable to the one of synchrotron light sources. Applications of this Thomson X-ray Source range from advanced radiological imaging to radio-therapy with micro-beams, from X-ray microscopy to national security applications. Studies are under way to assess the existence of FEL collective instabilities, in the classical and quantum regime, by operating the Thomson Source either with extremely high brightness beams or with very high laser pulse energies: we will discuss the experimental conditions under which the FEL instability can be driven and observed. This would produce coherent X-rays with much higher brilliance.
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Slides
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| WG343 |
Production of Coherent X-Rays with a Free-Electron Laser Based on Optical Wiggler
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- C. Maroli, V. Petrillo
Universita' degli Studi di Milano, Milano
- A. Bacci
INFN/LASA, Segrate (MI)
- M. Ferrario
INFN/LNF, Frascati (Roma)
- L. Serafini
INFN-Milano, Milano
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Funding: Istituto Nazionale di Fisica Nucleare(INFN) - Sezione di milano
The interaction between high-brightness electron beams and counter-propagating laser pulses produces X-rays via Thomson scattering. If the laser source is long enough the electrons bunch on the scale of the emitted X-ray wavelength and a regime of collective (coherent) emission can be established. The emitted radiation grows exponentially and the system behaves as a FEL with optical undulator. The bandwidth of the emitted X-rays is sharper than that of the usual incoherent emission. Emittance of the beam and gradients and irregularities of the laser intensity spatial distribution are the principal factors that limit the growth of the X-ray signal. The characters of the emission and the corresponding X-ray spectra are analyzed on the basis of a 3D code. The scalings typical of the optical wiggler with very short gain lengths and short time duration of the ineteraction allow considerable emissions also in violation of criteria valid for static wigglers. The parameters chosen in the cases examined allow a classical treatment of the lasing process.
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Slides
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