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| MOPPH054 | FERMI @ Elettra: A Seeded FEL Facility for EUV and Soft X-Rays | 166 |
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| We describe the conceptual design and major performance parameters for the FERMI FEL project funded for construction at the Sincrotrone Trieste, Italy. This user facility complements the existing storage ring light source at Sincrotrone Trieste, and will be the first facility to be based on seeded harmonic cascade FELs. Seeded FELs provide high peak-power pulses, with controlled temporal duration of the coherent output allowing tailored x-ray output for time-domain explorations with short pulses of 100 fs or less, and high resolution with output bandwidths of the order of meV. The facility uses the existing 1.2 GeV S-band linac, driven by electron beam from a new high-brightness rf photocathode gun, and will provide tunable output over a range from ~100 nm to ~10 nm, and APPLE undulator radiators allow control of x-ray polarization. Initially, two FEL cascades are planned, a single-stage harmonic generation to operate over ~100 nm to ~40 nm, and a two-stage cascade operating from ~40 nm to ~10 nm or shorter wavelengh, each with spatially and temporally coherent output, and peak power in the GW range. | ||
| THBAU03 | How to Obtain High Quality Electron Bunches in the Presence of Normal Conducting LINAC Wake Fields | 537 |
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| The dynamics of electron beams involved in Free Electron Lasers (FELs) projects is an interplay between sources of 6-dimensional emittance dilution and methods of emittance preservation. Relatively long bunches are required for harmonic cascade seeded FELs in order to accommodate the timing jitter and the seed provided by the bunch itself at each stage of the cascade. A high quality is required from such electron beams (small transverse emittance and energy spread) together with a uniform distribution in time along the usable part of the bunch; non-linearity in the longitudinal phase space and in the transverse planes are also issues. A complex longitudinal phase space dynamics characterizes the study often in presence of by the Coherent Synchrotron Radiation (CSR) generated in magnetic compressors. This paper reviews specific problems related to the electron beam dynamics dominated by bunches of kA peak current and varying length (0.1 to 2 ps) in the presence of normal conducting linac wakefields. Methods implemented to minimize the 6-dimensonal phase space degradation are discussed. Results of high beam quality performance are illustrated with particles tracking codes. | ||
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| THPPH029 | The Diagnostics of the FERMI@Elettra Bunch Compressors | 629 |
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Bunch compressors are key components of the single pass Linac based seeded FEL FERMI@ELETTRA. Assuring their stable operation, to reliably produce sub-psec electron bunches, requires multiple non-destructive diagnostics. Most of these diagnostics provide the error signals to the feedback systems used to stabilize the energy and the peak current of the electron bunch which are crucial parameters for optimum FEL operation. The different operation regimes foreseen for FERMI* call for a flexible set-up, for both the bunch compressors and the associated diagnostics. In this paper we present the adopted diagnostics for the measurement of position, energy and energy spread; both "energy" BPM, in between BC, and OTR screen plus wire scanner will be used. The design of a relative bunch length monitor needed for the determination of the optimal compression and for peak current stabilization is presented as well. The scheme is based on non-invasive techniques, namely the detection of the coherent synchrotron radiation (CSR) from the last bending of the BC plus the coherent diffraction radiation (CDR) from a downstream slit. Finally, a technique for the bunch phase measurement is presented.
* Study of the Electron Beam Dynamics in the FERMI @ ELETTRA Linac, M. Cornacchia, et al., Proc. of EPAC 2006 Conf., Scotland, UK (June 2006), to be published. |