ThomX is a compact x-ray source based on Compton scattering, installed at IJCLab (Laboratoire de physique des 2 infinis-Irène Joliot-Curie) in Orsay. The machine uses a small electron storage ring and an intense laser pulse stored in a high-finesse optical cavity. This article describes the various subsystems of the machine and their initial results of the commissioning, which began in mid-2021. This first commissioning phase led to the production of 10 10 x-rays/s with an on-axis energy of 45 keV. The main steps to be taken to reach the nominal flux are outlined at the end.

The optimization and advanced study of a laser-plasma electron injector are presented based on a truncated ionization injection scheme for high quality beam production. The smilei code is used with laser envelope approximation and a low number of particles per cell to reach computation time performances enabling the production of a large number of accelerator configurations. The developed and tested workflow is a possible approach for the production of a large dataset for laser-plasma accelerator optimization. A selection of functions of merit used to grade generated electron beams is discussed. Among the significant number of configurations, two specific working points are presented in detail. All data generated are left open to the scientific community for further study and optimization.

We report on the optical commissioning of the high power laser beam circulator for the high brightness Compton $\gamma$-ray source Extreme Light Infrastructure for Nuclear Physics. Tests aiming at demonstrating the optical performances of the laser beam circulator have been realized with a low-power pulsed laser-beam system and without electron beam. We show that, with the developed alignment and synchronization methods coming from the laser beam circulator design study presented in the Dupraz et al. paper [Phys. Rev. Accel. Beams 17, 033501 (2014)], the laser beam circulator enhances the laser-beam power available at the interaction point by a factor in excess of 25. This corresponds to a potential of bringing the average laser-beam power in excess of 1 kW when the laser beam circulator is injected with the interaction point laser-beam pulse energy of 400 mJ at 100 Hz.

Exploring novel target schemes for laser wakefield accelerators is essential to address the challenge of increasing repetition rates while ensuring the stability and quality of the produced electron beams. This paper introduces and discusses the prototyping of a two-chamber gas target, integrated into the beamline and operating under continuous gas flow, in the framework of ionization injection. We present the numerical fluid modeling employed to assist the density profile shaping, with a focus on gas mixing and dopant confinement. The importance of localized high-Z gas for ionization injection is demonstrated through particle-in-cell simulations using the simulated gas profiles. We describe the test bench used for prototype evaluation, specifically addressing the plasma electron density and the longitudinal distribution of species relevant to ionization injection. The lifetime of the target at 10 Hz and 60 mJ is measured for different materials, and its effect on the resulting electron beam is assessed using particle-in-cell simulations. Finally, we outline perspectives on high-power operation.