Development of laser remote analysis for nuclear fuel materials, 2-5; Study on plume dynamics by resonance imaging spectroscopy

Miyabe, Masabumi   ; Oba, Masaki ; Iimura, Hideki  ; Akaoka, Katsuaki ; Maruyama, Yoichiro; Oba, Hironori  ; Tampo, Motonobu; Wakaida, Ikuo  

We investigate dynamic behavior of ablation plume produced in background gas for nondestructive remote isotope analysis for a next-generation fuel. From our previous studies, it is expected that most of the ablated particles are concentrated on the surface of the plume in helium gas, and there is a cavity where few particles exists close to the ablation spot. In the present study actually we observed such plume structure using the laser-induced fluorescence images of Gd atoms and ions. It was also found that the minimum thickness of the layer where neutral atoms were concentrated was less than 0.5mm and the positions of the atomic layer was very close to that of ionic layer. From this observation, the neutral atoms are more likely to be produced as a result of recombination of the ions and electrons. The knowledge of the plume structure is thought be of importance in optimizing the experiment conditions for ablation analysis.