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

提出了一种新型离子源系统，由谐振电离激光器和烧蚀激光器组成的激光离子源和电荷增殖ECR离子源组成。本文综述了短寿命25Al的共振电离，激光烧蚀机理的研究，高性能电荷繁殖ECR离子源的构建。1)利用共振电离技术首次成功地实现了短寿命核25al （T1/2= 7,2秒）的选择性电离和连续在线质量分离。采用准分子激光和染料激光的组合调谐共振电离激光器。电离效率约为0.1%。2)利用激光诱导荧光光谱测量了Nd和Nd+在激光烧蚀羽流中的速度分布。烧蚀是由YAG激光产生并控制的。结果表明，在0.7 torr氩气中，中性离子和离子的速度分别比真空条件下低两个数量级和一个数量级。这种差异将用于从离子中选择中性。烧蚀颗粒在离烧蚀点20mm范围内加速。3)根据台架实验结果和ECR等离子体中离子的真实模拟，构建了包含新设计的减速系统的电荷增殖ECR离子源。该装置将安装在KEK-JAERI联合放射性核束设施中，用于使用重放射性核。

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.