Intense kJ-ns X-ray sources for the laser Megajoule

Intense X-ray sources have been developed to meet the experimental needs of the laser Megajoule, such as radiography analyses or data acquisition of highly irradiated materials. These sources are generated by the interaction of a kJ-ns laser with specific targets. Different target concepts were studied and validated by CEA - DAM, based on experimental campaigns and numerical simulations carried out with radiation-hydrodynamic codes. These were tested from the classical solid disks to the thin pre-exploded foils, using also metal-lined or aerogel-filled hohlraums, hybrid targets combining the hohlraums and foils, and laser gas-pipes. Emitting materials are the mid-Z elements (ranging from scandium to germanium), and the higher Z noble gases, such as argon, krypton and xenon. The optimization of the sources aimed at maximizing their X-ray conversion efficiency, and in some cases too, tailoring their emission lobes. The paper presents different concepts, and describes the performances of the sources tested at the CEA - DAM, exclusively or as part of collaborations on various facilities. (authors)