The quest of laser plasma accelerators is of great interest for various applications such as light sources or high energy physics colliders. This research has led to numerous performance improvements, particularly in terms of beam energy versus compactness [1] and ultra-short bunch length [2]. However, these performances are often reached without the achievement of sufficient beam quality, stability and reproducibility. These are the objectives of PALLAS, a test facility at IJCLab, that aims to advance laser-plasma from *acceleration* to accelerators. To this end, one of the main lines of research is the electron beam control and transport. The primary goal is to have a lattice design that allows for a fine characterization of the output beam as a function of the laser-plasma wakefield acceleration target cell and laser parameters, while paying a particular attention to preserving the quality of the beam during its transport. I will present the detailed strategy, considered for PALLAS, on the problematic of chromaticity and divergence for the transport of laser-plasma accelerated electron beams.

Inverse Compton Scattering is a promising technique to deliver compact, high brightness and high rate sources of photons ranging from few keVs to several MeVs. Current projects either focus on producing high rates of photons thanks to high-power (up to 300kW) enhancement optical cavities and electron storage rings or on providing low bandwidth photon sources based on room-temperature linacs. Burst mode operated optical enhancement cavities coupled to pulsed RF muti-bunch linac systems have the potential to provide high quality and high rate at the same time. To this end we concentrate on realizing innovative systems operated at GHz frequencies with repetition rates of several hundreds of hertz corresponding to linac RF-pulsing capabilities. Recent experimental advances, made within a collaboration between Amplitude and IJCLab, in the realization of a compact enhancement cavity seeded by a GHz laser and operated in burst mode are described. Performance will be reported along with prospects for improvements.

Inverse Compton scattering (ICS) is a method used for X-ray production that has been possible in recent years due to the rapid development of ultra-fast, short, and stable oscillators. In addition, the research and development of high Finesse Fabry-Perot Cavities to store high average power inside it. ThomX is a new generation of compact X-ray source which implements the ICS method. It will produce higher flux and better quality X-rays than the traditional sources such as X-ray tubes and be cheaper and more compact than synchrotrons. ThomX is currently being commissioned in IJCLab ( Laboratory de physique des 2 infinitis – Irene Joliot Curie ) at the Orsay campus. It is composed of a linear accelerator that can accelerate the electron bunch up to 50 MeV, an electron ring to store it over multiple revolutions at 16.66 MHz, and a Fabry Perot cavity to maintain the photon pulse at 33.33 MHz. The first electron beam produced was in October of 2021, and then it had a full round in the storage ring in 2022. It is expected to produce x-rays in mid-2023 when its Optical cavity has power stored in it. It is a high Finesse Fabry-Perot cavity that can store up to 1 MW. Such cavities face many problems, from high power stability to heating up of their reflecting mirrors. Here, we will describe the optical cavity commissioning of ThomX and the challenges faced throughout the preparation for the production of X-rays.

As part of the [EuPRAXIA](http://www.eupraxia-project.eu/) project[1], the objective of the PALLAS project is to produce an electron beam at 200 MeV, 30 pC with less than 5% energy spread and lower than 2μm normalised emittance using the IJCLAB-LaseriX laser driver at 10 Hz, 1.5 J and 35 fs. Based on available publications[2,3], we propose a two-chamber gas plasma target with a dopant localised in the first chamber. We then perform on-bench calibrated compressible simulations with the code [OpenFOAM](https://www.openfoam.com) to predict the density profile. The result is then used as input for two massive random scans and a Bayesian optimisation with [SMILEI](https://smileipic.github.io/Smilei/) fast Particle-in-Cell (PIC) simulation varying four input parameters: focal position, laser intensity, dopant concentration and inlet pressure. We further investigate the stability of the optimal working points. The massive amount of PIC results is left as open-source data for further investigation by the scientific community. Such a process can serve as the basis for any input parameters optimisation of a laser-plasma electron source target.

The quest of laser plasma accelerators is of great interest for various applications such as light sources or high energy physics colliders. This research has led to numerous performance improvements, particularly in terms of beam energy versus compactness [1] and ultra-short bunch length [2]. However, these performances are often reached without the achievement of sufficient beam quality, stability and reproducibility. These are the objectives of PALLAS, a test facility at IJCLab, that aims to advance laser-plasma from *acceleration* to accelerators. To this end, one of the main lines of research is the electron beam control and transport. The primary goal is to have a lattice design that allows for a fine characterization of the output beam as a function of the laser-plasma wakefield acceleration target cell and laser parameters, while paying a particular attention to preserving the quality of the beam during its transport. I will present the approach, considered for PALLAS, on the problematic of chromaticity and divergence for the transport of laser-plasma accelerated electron beams.

Laser-plasma electron beams are known for their large divergence and energy spread while having ultra-short bunches, which differentiate them from standard RF accelerated beams. To study the laser-plasma beam dynamics and to design a transport line, simulations with *CODAL* [1], a code developed by SOLEIL in collaboration with IJCLab, have been used. *CODAL* is a 6D 'kick' tracking code based on the symplectic integration of the local hamiltonian for each element of the lattice. *CODAL* also includes collective effects simulations such as space charge, wakefield and coherent synchrotron radiation. To validate the studies in the framework of Laser-Plasma Acceleratior developpement, results from *CODAL* have been compared to *TraceWin* [2], a well-known tracking code developed by CEA. The comparison has been made using the outcome of Laser WakeField Acceleration (LWFA) particle-in-cell simulations as initial start particle coordinates from a case study of PALLAS project, a Laser-Plasma Accelerator test facility at IJCLab.