Staples, J.W.
| Paper | Title | Page |
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| MOPP041 | Generation and Distribution of Stable Timing Signals to Synchronize RF and Lasers at the FERMI FEL Facility | 134 |
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Fermi is the fourth generation light source that is currently being designed at ELETTRA, in the frame of a collaboration that includes LBNL and MIT. The timing system will play a crucial role in achieving the expected performance of this and other Linac based FELs due to the sub-ps electron bunch length and the expanded use of fs-lasers as key components in future light sources. Furthermore, the requirements of the timing system are also tightly linked to the applications of the generated ultrafast x-ray pulses. In this paper we present the requirements for the FERMI timing system, which will be based on optical timing distribution concepts, currently seen to be the only technique to enable an RMS jitter at the 10fs level. The timing system, intended for a user facility that is operated on a 24-h, 7-d basis, must operate stable and reliable. The fundamental components of the system are analyzed, such as the optical reference oscillator, the fiber optic stabilized links and the local optical to electrical (O/E) converters, needed for the RF plant synchronization. Furthermore, solutions for the synchronization of the diagnostic tools for the Linac as well as user related synchronization issues are presented and discussed. |
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| FROA004 | Fiber Transmission Stabilization by Optical Heterodyning Techniques and Synchronization of Mode-Locked Lasers Using Two Spectral Lines | 686 |
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Funding: This work supported by the US Department of Energy under contract No. DE-AC03-76SF00098 Stabilization of the transit time through a glass fiber using an optical heterodyne technique promises to provide jitter reduction down to the few femtosecond level using inexpensive commodity hardware. An acousto-optical frequency shifter provides the optical frequency offset that is used to downconvert phase shifts at optical frequency to equivalent phase shifts at radio frequency which are used to close a phase-lock loop driving a piezoelectric phase shifter. Using the stabilized fiber transmission medium, two spectral lines of a mode locked laser lock two low-power CW lasers which are transmitted to a receiver which phase locks the same spectral lines of a second mode-locked laser to the first. The optical transmission system operates at low power and is linear, providing excellent signal-to-noise ratio and allows many signals to be transmitted without mutual interference. Experimental results will be presented. |
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| FROA003 | FERMI @ Elettra: A Seeded Harmonic Cascade FEL for EUV and Soft X-Rays | 682 |
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We describe the machine layout and major performance parameters for the FERMI FEL project funded for construction at Sincrotrone Trieste, Italy. The project will be the first user facility based on seeded harmonic cascade FELs, providing controlled, high peak-power pulses. With a high-brightness rf photocathode gun, and using the existing 1.2 GeV S-band linac, the facility will provide tunable output over a range from ~100 nm to ~10 nm, with pulse duration from 40 fs to ~ 1ps, and with fully variable output polarization. Initially, two FEL cascades are planned; a single-stage harmonic generation to operate > 40 nm, and a two-stage cascade operating from ~40 nm to ~10 nm or shorter wavelength. The output is spatially and temporally coherent, with peak power in the GW range. Lasers provide modulation to the electron beam, as well as driving the photocathode and other systems, and the facility will integrate laser systems with the accelerator infrastructure, including a state-of-the-art optical timing system providing synchronization of rf signals, lasers, and x-ray pulses. Major systems and overall facility layout are described, and key performance parameters summarized. |
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