| Paper | Title | Page |
|---|---|---|
| MOPPP062 | Soleil Emittance Reduction using a Robinson Wiggler | 702 |
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| For both synchrotron light sources as SOLEIL and colliders, the emittance is one of the key parameters to increase the photon brightness and the beam luminosity. In order to decrease the emittance, the ring optics is built on very focusing lattices leading to large chromaticities and potential reduction of the dynamics aperture and momentum transverse acceptance. Thus, some facilities have installed damping wigglers in zero dispersion straight sections to relax the optics and to reach sub-nanometer horizontal emittances. This solution requires however tens or hundreds meters of insertion devices. For storage ring equipped with zero-gradient bending magnets, an alternative solution can be given by installing a single Robinson wiggler [1] in a dispersive section enabling to divide the emittance by a factor 2. The uniqueness of this wiggler results from the presence of an alternated gradient superimposed the main periodic magnetic field. This paper recalls the concept of the wiggler, presents the expected gain for SOLEIL storage ring with the impact on the linear optics and the brightness. A preliminary magnetic design is also proposed. [1] K.W. Robinson, Phys. Rev, p. 373 (1958). | ||
| TUPPP005 | LUNEX5: A French FEL Test Facility Light Source Proposal | 1611 |
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| LUNEX5 is a new synchrotron FEL source project aiming at delivering short and coherent X-ray pulses to probe ultrafast phenomena at the femto-second scale, to investigate extremely low density samples as well as to image individual nm scale objects. The proposed machine layout is based on a 400 MeV super-conducting Conventional Linear Accelerator (CLA) mainly composed of 2 XFEL type cryo-modules together with a normal-conducting high brightness photo RF gun. This present mature and reliable technology is able to deliver high quality electron bunches up to few kHz suitable for user experiments. Further more, the last decade improvement in synchronization and stability offer a fertile land to explore the different and innovative seeded FEL operations aiming at producing higher coherence and energetic X-rays for the pilot user full benefits. In parallel of the CLA branch, the very promising and highly innovative Laser Wake-Field Accelerator (LWFA) able to produce very short electron bunches in the range of the femto-second and high peak current up to few GeV is foreseen as a FEL bench test using the same undulator lines. | ||
| TUPPP048 | Increasing the Spectral Range of the CLIO Infrared FEL User Facility by Reducing Diffraction Losses | 1709 |
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Funding: CNRS/RTRA The infrared free-electron laser offers a large tunability since the FEL gain remains high throughout the infrared spectral range, and the reflectivity of metal mirrors remains also close to 1. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator. At CLIO, we have obtained previously* an FEL tunable from 3 to 150 μm by operating the accelerator between 50 and 14 MeV. However, we found that a phenomenon of “power gaps“ is observed in far-infrared : the laser power falls down to zero at some particular wavelengths, whatever the beam adjustments are. We showed that this effect is related to to the waveguiding effect of the vacuum chamber leading to different losses and power outcoupling at different wavelengths**. To alleviate this effect we have designed a new undulator allowing to use a larger vacuum chamber without reducing the spectral tunability and agility of the FEL. From simulations, a large increase of available power is expected in far-infrared. The new undulator has been installed and its performances and first FEL measurement in far-infrared will be presented * J.M. Ortega, F. Glotin, R. Prazeres Infrared Physics and Technology, 49, 133 (2006) ** R. Prazeres, F. Glotin, J.-M. Ortega Phys. Rev. STAB12, 010701 (2009) |
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| TUPPP050 | FEL Performances of the French LUNEX5 Project | 1712 |
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| LUNEX5 is a french FEL test facility project based on two types of accelerators: a 400 MeV Conventional Linear Accelerator (CLA) and a Laser WakeField Accelerator (LWFA). The FEL performances will be presented at 20 nm and at 12 nm, wavelengths of interest for the pilot experiments. Results are obtained with GENESIS simulations in time-dependent mode. With the CLA, we compare different seeded schemes as EEHG scheme (Echo Enabled Harmonic Generation) or HGHG scheme (High Gain Harmonic Generation) using HHG source (High Harmonic in Gaz). In parallel, LWFA FEL performances will be presented as a function of the electron bunch characteristics, in particular the bunch length and the energy-spread. The transport of the LWFA output beams into undulators which is found to be a critical issue will be also discussed. | ||