NATALIE, a multidetector diagnostic to characterize laser produced particle beams. Applications

Complete text of publication follows. Ultra High Intensity lasers produce energetic particles such as electrons, protons, photons within a large domain of energies. In a range between a few MeV to few tens of MeV, these beams may open new opportunities to study nuclear isomer production in plasma in relation with astrophysical problems. Such studies require the knowledge of the particle energy and angular distributions to quantify possible future experiments. For this purpose, we have developed a standalone integrated data acquisition system to characterize proton and electron beams (converted into photons via bremsstrahlung) using nuclear activation techniques. This system called NATALIE (Nuclear Activation Technique for Analysis of Laser Induced Energetic particles) is composed of sixteen NaI detector pairs used to count the activity of various samples activated via (γ,xn) or (p,n) reactions for example. The setup is based on a coincident technique which allows β+ activity measurements with very low background and leads to accurate nuclear activation yields determination. Geant4 simulations are used at different steps of the data analysis to deduce the energy and angular distributions of the laser-induced particle beams from the experimental data. Two applications are presented as illustrations regarding the characterization of electron and proton beams. Acknowledgements. We acknowledge the support of IN2P3/Region Aquitane for a BDI grant (C.P.) and financial supports from ANR (contract no. ANR-07-JCJC-0158), Conseil Regional d'Aquitane (contract no. 200713040005) and IN2P3/CNRS.