Preparation and characterization of highly lead-loaded red plastic scintillators under low energy x-rays

To the aim of development of a spatially resolved x-ray imaging system intended for Inertial Confinement Fusion (ICF) experiments at the Laser Méga Joule (LMJ) facility, new plastic scintillators have been designed. The main characteristics are the following: fast decay time, red emission and good x-rays photoelectric absorption in the range 10-40 keV. These scintillators are synthesized by copolymerization of different monomers with an organometallic compound. In this matrix two fluorescent compounds are embedded, allowing to shift the energy from the UV to the near IR spectrum. Several parameters were studied: fluorophores concentration, nature of the secondary fluorophore and lead concentration. An outstanding effective atomic number of 53 has been reached, for a loading of lead corresponding to 29 wt%. Thus, small cylinders were prepared and their performances under x-ray beam studied and compared with those of inorganic Cerium-doped Yttrium Aluminum Garnet reference scintillator (Y3Al5O12:Ce3+). Eventually, such new scintillators or their next generation could replace expensive and brittle inorganic scintillators, inducing a strong industrial potential.