Development of an X-ray Imaging System for the Laser Megajoule

This system intends to record spatially resolved images of core shape and size of a DT micro-balloon during fusion experiments for the Megajoule Laser. It must operate in the radiation background generated by fusion reaction. It consists of a scintillator imaged by an optical relay system on a CCD camera. The latter lies in a shielded area far from the experiment chamber. This design proposes a simple solution for the optical relay, based on Maksutov objectives. The main requirements affect the scintillator (short duration emission), and the optical relay (length of 15 meters, no Cerenkov radiation production, spatial resolution better than 10 μm in the object plane). Spatial resolution and performances to radiative background have been measured on a system shorter than 15 meters, with a YAG:Ce scintillator. Pinhole images have been obtained on the plasma laser facility EQUINOX at CEA/DIF. Hardening measurements have been achieved at the ELSA facility