Ablation and Its Product of the Fast Ignition Inertial Confinement Fusion Reactor Chamber

One of the major problems in the technological feasibility of the inertial confinement fusion reactor is the chamber that should accept pulsed load of radiation, ion particles and debris and be pumped out in the repeated pulsed operation cycle of several Hz. Especially in a fast ignition scenario, lead (or lithium lead) cone attached to the target fuel pellets adds specific material transfer issues such as deposited on the chamber wall, ablation, and formation of clusters that is suspected to affect the pumping characteristics. Ablated metal particles from the wall are suspected to form various sizes of clusters that fly slower and more difficult to evacuate. Therefore, it is necessary to investigate behavior of the chamber wall under simulated laser fusion condition by the experiments as well as numerical studies. In this study, we have made the preliminary experiments to investigate formation of cluster of plastic and metals. The YAG laser (2J, 10ns) was irradiated on the targets, and the ablated particles are measured using the Thomson parabola, the charge particle collector, and the quadrupole mass spectrometer. Results show formations cluster of ethylene (-CH₂ -)_n and metals, and ablation of metals by bombardments by ethylene debris