| Paper | Title | Page |
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MOP004 |
Optimization of APPLE-II Quasiperiodic Undulators at SOLEIL and Spectral Peformances | |
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| The introduction of a slight aperiodicity in an undulator enables to generate irrational harmonics, for the distinction between a one or two photon process. In the case of an APPLE-II undulator generating various types of polarizations, the aperiodicity is generally introduced by shifting vertically some magnets on arrays. The optimization of the system is not fully satisfying since different optima of magnet displacements are found for the various polarization modes, as reported in examples from SOLEIL undulators. Besides, the intensity of the first harmonics is slightly reduced. In addition, a residual photon signal appears between pseudo-harmonics. Measured spectra from built APPLE-II undulators at SOLEIL are compared to calculated ones from magnetic measurements, and confirm these observed trends, and in particular the residual structure between the pseudo-harmonics. An analytic approach is given and consequences for scientific applications are also driven. | ||
| TUP086 | Experiment Preparation Towards a Demonstration of Laser Plasma Based Free Electron Laser Amplification | 569 |
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| One direction towards compact Free Electron Laser is to replace the conventional linac by a laser plasma driven beam, provided proper electron beam manipulation to handle the value of the energy spread and of the divergence. Applying seeding techniques also enables to reduce the required undulator length. Rapidly developing Laser Wakefield Accelerators (LWFA) are already able to generate synchrotron radiation. With the presently achieved electron divergence and energy spread an adequate beam manipulation through the transport to the undulator is needed for FEL amplification. A test experiment for the demonstration of FEL amplification with a LWFA is under preparation in the frame of the COXINEL ERC contract in the more general context of LUNEX5. Electron beam transport follows different steps with strong focusing thanks to variable strength permanent magnet quadrupoles, demixing chicane with conventional dipoles, and a second set of quadrupoles for further focusing in the undulator. Progress on the equipment preparation and expected performance are described. | ||
| TUP087 | The Status of LUNEX5 Project | 574 |
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| LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating the production of short, intense, coherent Free Electron Laser (FEL) pulses in the 40-4 nm spectral range. It comprises a 400 MeV superconducting Linear Accelerator for high repetition rate operation (10 kHz), multi-FEL lines and adapted for studies of advanced FEL schemes, a 0.4 - 1 GeV Laser Wake Field Accelerator (LWFA) for its qualification by a FEL application, a single undulator line enabling seeding with High order Harmonic in Gas and echo configurations and pilot user applications. Concerning the superconducting linac, the electron beam dynamics has been modified from a scheme using a third harmonic linearizer and a compression chicane to dog-leg coupled to sextupoles. Besides, the choice of the gun is under revision for fulfilling to 10 kHz repetition rate. Following transport theoretical studies of longitudinal and transverse manipulation of a LWFA electron beam enabling to provide theoretical amplification, a test experiment is under preparation in collaboration with the Laboratoire d’Optique Appliquée towards an experimental demonstration. | ||