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Title |
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| TUPPH027 |
The Experimental Research of the SR-FEL Cavity Mirrors at 355nm and 248nm
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382 |
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- H. L. Gao, R. Q. Tan, D. L. Wang, Y. Wang, J. Wu
Institute of Electronics, Chinese Academy of Sciences, Beijing
- N. Y. Wang
CIAE, Beijing
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The cavity mirrors of the storage-ring free-electron laser (SR-FEL) at 355nm and 248nm central wavelengths have been investigated experimentally with the optical coating materials of Al2O3/HfO2/SiO2 on fused silica. They were deposited by the electron-beans evaporation technology and ion-beam sputtering technology, so that the mirror have high damage threshold to laser pulse and resist to the reflectance degeneration- induced by the synchrotron radiation. The experimental results show that the absolute reflectance of the broad-band mirror at reaches up to R=99.45%, the frequency-tunable range with reflectance higher 99.00% is 406nm-331nm=75nm. For the dual-central wavelength mirror, the absolute reflectance are R(248nm)=98.21% and R(355nm)= 99.69%. The frequency-tunable range is 373nm-314nm for 355nm central wavelength; 275nm-272nm and 240nm-234nm for 248nm central wavelength, it isn't continual due to the absorption of HfO2 optical materials. All of the samples have passed the high-temperature test under the condition 400°C-4hrs successfully, and shown very stable optical property.
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| MOPPH063 |
Coherent X-Ray Production by Cascading Stages of High Gain Harmonic Generation Free Electron Lasers Seeded by IR Laser Driven High-Order Harmonic Generation
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186 |
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- J. Wu, P. R. Bolton
SLAC, Menlo Park, California
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Coherent x-ray production achieved by seeded free electron lasing with cascaded high gain harmonic generation (HGHG) is important for next generation development of synchrotron light sources. We examine the feasibility and some features of FEL emission seeded by a high order harmonic of an intense infrared conventional laser source (HHG). In addition to the intrinsic FEL chirp phenomenon, the longitudinal profile and spectral bandwidth of the HHG seed are modified significantly by the FEL interaction well before saturation occurs. This smears out the original attosecond pulselet structure. As an example, we describe a cascaded HGHG scheme for coherent x-ray FEL generation that is seeded by the twenty-seventh harmonic of an ultrashort 800 nm laser pulse with 10 fs rms duration. Given the multiple order HHG spectrum, proof-of-principle experiments using lower order harmonics can also be considered.
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| MOPPH054 |
FERMI @ Elettra: A Seeded FEL Facility for EUV and Soft X-Rays
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166 |
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- J. N. Corlett, L. R. Doolittle, W. M. Fawley, S. M. Lidia, G. Penn, I. V. Pogorelov, J. Qiang, A. Ratti, J. W. Staples, R. B. Wilcox, A. Zholents
LBNL, Berkeley, California
- E. Allaria, C. J. Bocchetta, D. Bulfone, F. C. Cargnello, D. Cocco, P. Craievich, G. D'Auria, M. B. Danailov, G. De Ninno, S. Di Mitri, B. Diviacco, M. Ferianis, A. Galimberti, A. Gambitta, M. Giannini, F. Iazzourene, E. Karantzoulis, M. Lonza, F. M. Mazzolini, G. Penco, L. Rumiz, S. Spampinati, G. Tromba, M. Trovo, A. Vascotto, M. Veronese, M. Zangrando
ELETTRA, Basovizza, Trieste
- M. Cornacchia, P. Emma, Z. Huang, J. Wu
SLAC, Menlo Park, California
- W. Graves, F. X. Kaertner, D. Wang
MIT, Middleton, Massachusetts
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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.
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