Development of rf ion guide for trapping unstable Be isotopes and their precision hyperfine structure spectroscopy

新一代慢放射性核离子束装置（SLOWRI）是日本理化研究所（RIKEN）的主要实验设备之一，该装置可提供所有元素的慢、高纯度和小发射度离子束。高能放射性离子束从弹丸碎片分离器BigRIPS在一个大型气体捕集池中热化。气体电池中的热化离子通过直流电场和电池内不均匀射频场的组合引导和提取到真空中（射频离子引导）。在日本理化学研究所的研发工作中，从现有的弹丸碎片分离器RIPS中获得了【大约等于】5%的【大约等于】100A MeV ^8Li离子束的总效率，并研究了效率与束流强度的关系。在原型机SLOWI上对Be同位素进行了第一次光谱实验。来自RIPS的^<10>Be和^7Be高能离子被捕获并在线性射频阱中激光冷却，并首次测量了这些同位素的比质量位移。

A next-generation slow radioactive nuclear ion beam facility (SLOWRI) which provides slow, high-purity and small emittance ion beams of all elements has been proposed as one of the major experimental facilities at the RIKEN RI-beam factory (RIBF). High energy radioactive ion beams from the projectile fragment separator BigRIPS are thermalized in a large gas catcher cell. The thermalized ions in the gas cell are guided and extracted to vacuum by a combination of DC electric fields and inhomogeneous RF fields in the cell (RF ion guide). In the R&D works at the present RIKEN facility, an overall efficiency of 【approximately equal】5% for 【approximately equal】100A MeV ^8Li ion beam from the present projectile fragment separator RIPS was achieved and the dependence of the efficiency on the beam intensity was investigated.A first spectroscopy experiment at the prototype SLOWI was performed on Be isotopes. Energetic ions of ^<10>Be and ^7Be from the RIPS were trapped and laser cooled in a linear RF trap and the specific mass shifts of these isotopes were measured for the first time.