| Paper | Title | Page |
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| MOPCH047 | Study of the Electron Beam Dynamics in the FERMI @ ELETTRA Linac | 145 |
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A study of the electron beam dynamics in the linac is made within the framework of the design of a free electron laser (FEL) at the Syncrotrone Trieste*. A scope of the work includes analysis of two operational scenarios, one with relatively long electron bunches of the order of 1.5 ps and a moderate peak current of 500 A and one with shorter bunches of the order of 0.7 ps and higher peak current of the order of 800 A. In both cases, care has been taken to preserve the slice and projected emittances formed in the photocathode gun injector and to minimize the slice energy spread. The latter goal is accomplished by balancing the onset of the microbunching instability driven by the longitudinal space charge forces and the emission of coherent synchrotron radiation using Landau damping produced by a so-called laser heater. Various analytical techniques and tracking codes have been employed to obtain the reported results.
*C. Bocchetta, et al., this conference. |
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| MOPCH021 | FERMI @ Elettra: Conceptual Design for a Seeded Harmonic Cascade FEL for EUV and Soft X-rays | 0 |
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| We present a summary of the conceptual design for the FERMI FEL project funded for construction at the Sincrotrone Trieste, Italy. The project will be the first user facility based on seeded harmonic cascade FEL's, providing controlled, high peak-power pulses, and complementing the storage ring light source at Sincrotrone Trieste. The facility is to be driven by electron beam from a high-brightness rf photocathode gun, and using the existing 1.2 GeV S-band linac. Designed for an initial complement of two FEL's, providing tunable output over a range from ~100 nm to ~10 nm, FERMI will allow control of pulse duration from less than 100 fs to approximately1 ps, and with polarization control from APPLE undulator radiators. Seeded by tunable UV lasers, FEL-1 is a single-stage of harmonic generation to operate over ~100 nm to ~40 nm, and FEL-2 a two-stage cascade operating from ~40 nm to ~10 nm or shorter wavelength. Photon output is spatially and temporally coherent, with peak power in the 100’s MW to GW range. We have designed FEL-2 to minimize the output radiation spectral bandwidth. Major systems and overal facility layout are described, and key performance parameters summarized. | ||
| THOPA01 | Formation of Electron Bunches for Harmonic Cascade X-ray Free Electron Lasers | 2738 |
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| A relatively long electron bunch is required for an operation of harmonic cascade free electron lasers (FELs). This is because they repeatedly employ a principle when the radiation produced in one cascade by one group of electrons proceeds ahead and interacts with other electrons from the same electron bunch in the next cascade. An optical laser is used to seed the radiation in the first cascade. Understandably the length of the electron bunch in this situation must accommodate the length of the x-ray pulse multiplied by a number of cascades plus a time jitter between the arrival time of the electron bunch and a seed laser pulse. Thus a variation of the peak current along the electron bunch as well as slice energy spread and emittance may affect the performance of the FEL. In this paper we analyze all possible sources affecting the distributions and interplay between them and show how desirable distributions can be produced. Results are illustrated with simulations using particle tracking codes. | ||
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| THPLS083 | Implementation of the Double-waist Chicane Optics in SPEAR 3 | 3472 |
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| The SPEAR 3 upgrade produced two new 7.6 m racetrack straight sections in the 18 cell, 234 m magnet lattice. One of these straights houses four PEP-II style mode-damped RF cavities. The other straight will accommodate two new small-gap insertion devices separated by 10mrad in a magnetic chicane configuration. A quadrupole triplet has been installed at the midpoint of the chicane and the vertical tune has been raised by an integer to create a 'double waist' optics with betay = 1.6m in the center of each ID. Furthermore, as part of the optics upgrade, betay in the four straights adjacent to the racetrack sections was reduced from 5m to 2.5m. In this paper, we describe the physical implementation of the double-waist chicane optics and initial operational results. |