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.

Particle accelerators are devices of primary importance in a large range of applications such as fundamental particle physics, nuclear physics, light sources, imaging, neutron sources, and transmutation of nuclear waste. They are also used every day for cargo inspection, medical diagnostics, and radiotherapy worldwide. Electron is the easiest particle to produce and manipulate, resulting in unequaled energy over cost ratio. However, there is an urgent and growing need to reduce the footprint of accelerators in order to lower their cost and environmental impact, from the future high-energy colliders to the portable relativistic electron source for industrial and societal applications. The radical new vision we propose will revolutionize the use of accelerators in terms of footprint, beam time delivery, and electron beam properties (stability, reproducibility, monochromaticity, femtosecond-scale bunch duration), which is today only a dream for a wide range of users. We propose developing a new structure sustaining the accelerating wave pushing up the particle energy, which will enable democratizing the access to femtosecond-scale electron bunch for ultrafast phenomena studies. This light and compact accelerator, for which we propose breaking through the current technological barriers, will open the way toward compact accelerators with an energy gain gradient of more than 100 MeV/m and enlarge time access in the medical environment (preclinical and clinical phase studies).

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.

Based on an initial proof-of-concept, a full-size single-piece pure-copper Radio Frequency Quadrupole (RFQ) prototype module was for the first time designed and additively manufactured (AM), as a result of a multi-disciplinary collaborative effort and of the deployment of state-of-art AM technology. The 39-cm long prototype with modulated electrodes replicates, with several improvements allowed by AM, the design of the CERN high-frequency (750 MHz) RFQ that has already found applications in proton therapy of cancer and ion beam analysis. Thanks to its unique features, AM technology is unlocking great potential for the optimisation of a complex accelerating cavity like the RFQ. The RFQ geometry can be improved based only on accelerator physics and functional requirements without considering limiting factors (e.g. tolerances, shape, size and configuration) imposed by the conventional manufacturing techniques. Additionally, cooling channels and connection flanges can be integrated in the overall structure, with a gain in installation and operation flexibility. In-depth geometrical accuracy and surface roughness measurements were performed on the proof-of-concept prior and after the surface treatment operations. The results are fully in line with the standard RFQ requirements. Vacuum, RF and water tightness tests are being performed on the full prototype. The paper will discuss in detail the technological process, the measurements and the test results.