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Objective of ESCULAP project is the experimental study of Laser-Plasma Acceleration (LPA) of relativistic electron bunch from photo-injector in 10 cm length plasma cell *. In parallel, numerical tools have been developed in order to optimize the setup configuration and the analysis of the expected results. The most important issue when dealing with numerical simulation over such large interaction distances is to obtain a good accuracy at a limited computing cost in order to be able to perform parametric studies. Reduction of the computational cost can be obtained either by using state-of-the-art numerical technics and/or by introducing adapted approximation in the physical model. Concerning LPA, the relevant Maxwell-Vlasov equations can be numerically solved by Particle-In-Cell (PIC) methods without any additional approximation, but can be very computationally expensive. On the other hand, the quasi-static approximation ***, which yields a drastic reduction of the computational cost, appears to be well adapted to the LPA regime. In this paper we present a detailed comparison of the performance, in terms of CPU, of LPA calculations and of the accuracies of their results obtained either with a highly optimized PIC code (FBPIC **) or with the well known quasi-static code WAKE ***. We first show that, when considering a sufficiently low charge bunch for which the beam loading effect can be neglected, the quasi-static approximation is fully validated in the LPA regime. The case of a higher bunch charge, with significant beam loading effects, has also been investigated using an enhanced version of WAKE, named WAKE-EP. Additionally, a cost evaluation, in terms of used energy per calculation, has also been done using the multi-CPU and multi-GPU versions of FBPIC., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

Coherent Smith Purcell radiation allows the measurement of a beam longitudinal profile through the study of the emission spectrum of the radiation emitted when a grating is brought close from the beam. In order to increase the dynamic range of our measurements we have used several gratings and we report on the measured bunch form factor using this technique. We report on these measurements and on the background rejection used., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The ESCULAP project aims at studying external injection of low energy (\SI{10}{MeV}) electrons in a plasma in the quasilinear regime. This facility will use the photo injector PHIL and the high power laser LASERIX. We will give a status report of the preliminary work on the facility and the status of the two machines. We will also present the results of simulations showing the expected performances of the facility., Comment: EAAC'17

The plasma acceleration project ESCULAP (ElectronS CoUrts pour L'Acc\'el\'eration Plasma) aims at studying electrons injection into a laser plasma accelerator. This requires the injection of short electron bunches generated by the photo injector PHIL (Photo injector at LAL) into a plasma wave by the high power femtosecond Laser LASERIX. As a first step we have studied how to synchronize PHIL and LASERIX. As these two machines had not been initially designed to work together, simple synchronization solutions were not available. We detail here the synchronisation scheme that we have tested and the experimental results obtained., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

We report on measurements of Coherent Smith-Purcell radiation at the CLIO Free Electron Laser. Smith-Purcell radiation is emitted when a grating is brought close from a bunch of relativistic particles. When the bunch is sufficiently short coherent radiation is emitted. This coherent radiation encodes the longitudinal form factor of the bunch and can therefore be used as a longitudinal profile monitor. With its short pulses and high charge the 45 MeV Linac of CLIO is a good location to test advanced longitudinal profile diag- nostics. The results will be compared with measurements using the RF dephasing. induced energy dispersion., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

CLIO is a Free Electron Laser based on a thermionic electron gun. In its normal operating mode it delivers electron 8 pulses but studies are ongoing to shorten the pulses to about 1 ps. We report on simulations showing how the pulse can be shortened and the expected signal yield from several bunch length diagnostics (Coherent Transition Radiation, Coherent Smith Purcell Radiation)., IPAC16 MOPMB005

Dissertação de mestrado integrado em Arquitectura (área de especialização em Cultura Aquitectónica), O impacto da dimensão digital na realidade traz uma série de consequências críticas ao pensamento fundamental sobre as relações entre os espaços. Nesse sentido, propõe-se uma análise sistémica que, embora fragmentada na sua constituição original, se encontra interconectada nos assuntos de conteúdo teórico e numa vertente prática assumida/representada pelas redes de informação sobre os lugares (não necessariamente contíguos). Seguindo este princípio, palavras como espaço, tempo, corpo, ligação, alienação e fragmentação funcionam como nós de organização espacial, numa tentativa de diálogo interno e que expresse a capacidade de performance do ciberespaço. Importa referir, de resto, que tal diálogo permanece ainda fragmentado em três momentos, a saber: separação; complementaridade; e ambiguidade; exprimem o resultado de uma relação entre as dicotomias A separação (ou seja, a alteridade) é implícita ao espaço e ao tempo quando já não existe necessariamente um tempo e/ou um lugar (ou seja, um acontecimento) para a experiência singular ou colectiva. Neste sentido, pois, parece tornar-se evidente que a complementaridade (ou seja, o eros) entre o corpo e a ligação resulte como potencial extensão das redes, libertando então o sujeito das restrições e limitações locais. Como consequência, a ambiguidade presente entre realidade e ciberespaço deriva do seu diálogo constante., The impact of the digital dimension, upon the realm of the real, brings a series of critical consequences that demand a fundamental rethinking of the spatial relationships. In this sense, we propose an ideological analysis that, although fragmented in its formal constitution, is interconnected within the affairs of its theoretical content, as a practical attempt to demonstrate the effect of relationship between places seemingly unrelated, created by information networks. Following this principle: space, time, body, connection, alienation and fragmentation, work as nodes, connected by the fundaments of spatial organization, in an attempt to create a relationship of internal dialogue that may express the transformative capacity of cyberspace. This dialogue is divided into three moments that express the result of the relationship between dichotomies (separation, complementarity, ambiguity). The separation between space and time, which is suggested by the fact that, we no longer need a particular time or space for anything. The complementarity between body and connection that, as the result of an augmented by the connection body, sets the subject free of regular restrictions and limitations set by the local. The ambiguity existing between reality and cyberspace, created by its constant dialogue.

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 unity. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator. A solution is to use this chamber as a waveguide by adaptating the radius of curvature of the cavity mirrors to this regime. Then, as has been shown before* a minimum appears in the spectrum that can be produced by the FEL. We discuss the physical mechanism of this particular regime and compare it to experiments using vacuum chambers of different tranverse sizes. A good agreement is found with results of simulations and with a simple analytical formula., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

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International audience