Development of an element-selective ion-source system ofr the study of radioactive nuclei by means of the muonic X-ray spectroscopy

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A proposed new ion-source system consists of the laser ion-source including the resonant ionization laser and the ablation laser, and the charge-breeding ECR ion-source. Research summaries of developments, 1) a resonant ionization of the short-lived 25Al, 2)a study of the laser ablation mechanism, and 3)a construction of the high-performance charge-breeding ECR ion-source, are followings.1)A selective ionization and successive on-line mass-separation of the short-lived nuclei25Al(T1/2=7, 2sec.) was succeeded for the first time by means of the resonant ionization technique. The resonant ionization laser was tuned with the combination of the excimer laser and dye laser. The ionization efficiency was about 0.1%.2)Velocity distributions of Nd andNd+ in the laser ablation plume was measured by the laser unduced fluorescence spectroscopy. The ablations was produced and were controlled by the YAG laser. It was found that the velocities or neutrals and ions in the 0.7 torr Ar-gas was lower than those in the vacuum circumstance by the tow orders of magnitude and one order of magnitude, respectively. This difference will be utilized for the selection of neutrals from ions. It was also found that the ablated particles were accelerated within the 20 mm from ablation point.3)On the basis of the result of the test-bench experiments and the realistic simulation of ions in ECR-plasma, a charge-breeding ECR ion-source including the newly designed deceleration system was constructed. This device will be installed in the KEK-JAERI joint radioactive nuclear beam facility for the use of heavy radioactive nuclei.