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.

We will report on the ongoing ThomX ring commissioning, its status, its main challenges, our results and our planning. ThomX is a compact Compton-based X-ray source under commissioning at IJCLab in Orsay (France). This facility is composed of a 50-70 MeV linac, a transfer line and a storage ring whose closed orbit is 18 m long. Compton scattering between the 50 MeV electron bunch of 1 nC and the 30 mJ laser pulses stacked in a Fabry-Perot cavity results in the production of X-rays with energy ranging between 45 keV and 90 keV. We aim at a total flux of about 10^13 X-rays per second. The injector commissioning started in the spring of 2021. The ongoing storage ring commissioning faces many challenges due to the ring’s low energy, its compactness, its non-linear beam dynamics, the time-limited beam storage and the need to achieve a very accurate and stable geometry of the collision region between the laser pulses and the electron bunch. The commissioning and operational experience is of great importance for the future Compton sources.

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.

We report on the behaviour and tuning of the diagnostics of the ThomX Compact source during the accelerator commissioning. These diagnostics consist of Beam Position Monitors, screens used to measure the beam profile (YAG and OTR), charge monitors, bunch length monitors, beam loss monitors and synchrotron radiation monitors. For each diagnostics we report on the performances measured with the beam and the difficulties encountered.

Spatio-temporal couplings (STCs) [1] can have a detrimental effect on the intensity at focus of ultrashort femtosecond lasers. The laser spatio-temporal intensity profile control is a key issue for stable operation of laser wakefield acceleration (LWFA) [2]. Thus, it is necessary to measure and correct STCs. Techniques such as INSIGHT [3] or TERMITES [4] allow reconstructing the full spatial phase for different spectral components of the laser pulse using a phase-retrieval iterative algorithm. However this requires a computing time of the order of several minutes, making it inappropriate for single-shot online monitoring of lasers running at repetition rates of several hertz. We propose a method to characterize STCs in real-time using a multispectral camera [5] coupled with wavefront and temporal measurements and a machine learning algorithm. We will present the sensitivity characterization of the STCs measurement, which has been tested at 10 Hz for the optimization of a large optical compressor. Finally, we will discuss the status of the reinforcement learning implementation for full laser field reconstruction.