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

RIKEN放射性核离子束工厂（RIBF）的主要实验设施之一是下一代慢放射性核离子束设施（SLOWRI），该设施可提供所有元素的慢、高纯度和小发射度离子束。来自弹丸碎片分离器BigRIPS的高能放射性离子束在大型气体捕集器单元中热化。气体单元中的热化离子通过单元中的DC电场和非均匀RF场的组合（RF离子引导器）被引导和提取到真空。在RIKEN现有设施的研发工作中，对来自现有射弹碎片分离器RIPS的100 A MeV^8Li离子束，实现了[约等于]5%的总效率，并研究了效率对束流强度的依赖性。在SLOWI原型上对Be同位素进行了第一次光谱实验。用<10>线性射频阱捕获并激光冷却了来自RIPS的高能离子^ Be和^7Be，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.