Investigation of the rare-abundant naturally-occurring long-lived radioisotopes by nuclear laser spectroscopy

稀有的丰度高的自然存在的长寿命放射性同位素，如^&lt；50&gt；V，^&lt；138&gt；La，^&lt；176&gt；Lu是接近中子幻数的原子核。这种原子核不仅对核物理学，而且对测年和天体物理学都有特别的兴趣。在这个项目中，我们进行了核激光光谱分析，以了解此类原子核的超精细结构、电荷分布和核矩。利用我们研制的高分辨率半导体激光光谱装置，我们将测量范围扩展到轻元素，如^&lt；；Y，并测定了其超精细常数和g因子。还研究了与宇称非守恒有关的斯塔克效应。观测到了Rb 5s^2S&lt；1/2&gt；→5p^2P&lt；1/2&gt；Cs 6s^2S&lt；1/2&gt；→6p^2P&lt；3/2&gt；852 nm跃迁的斯塔克光谱，得到了Rb和Cs的标量和张量极化率。特别是，为了测量稀有丰富的自然存在的放射性同位素，我们将倍频系统与半导体激光器相结合，获得了高分辨率的紫外光光源，最高可达100μW。利用高分辨实验装置和紫外光光源，我们成功地实现了紫外区~(27)Al的高分辨核激光能谱。首次测定了包括基态在内的四个原子能级的超精细常数。利用强紫外光跃迁对稀有丰度的自然长寿命核^&lt；176&gt；Lu进行了核激光光谱测量，得到了^&lt；176&gt；Lu和^&lt；175&gt；Lu的超精细常数，得到了^&lt；176-175&gt；Lu的同位素位移。我们的一些结果已经被报道了，其中大部分将在其他地方发表。

The rare-abundant naturally-occurring long-lived radioisotopes, such as ^<50>V,^<138>La,^<176>Lu are the nuclei near the neutron magic numbers. Such nuclei are of particularly interests not only for nuclear physics but for dating and astrophysics. In this project, we carried out nuclear laser spectroscopy in order to understand hyperfine structures, charge distribution and nuclear moments of such nuclei. Using our developed high-resolution diode-laser spectroscopic setup, we expanded our measurements to light elements, such as ^<89>Y, and determined its hyperfine constants and g factors. The Stark effect, related to the parity non-conservation, was also investigated. Stark spectra were observed for the Rb 5s^2S_<1/2>→5p ^2P_<1/2> transition at 795 nm and for the Cs 6s^2S_<1/2>→6p^2P_<3/2> transition at 852 nm with the change of the electric field up to 40 keV/cm, and scalar and tensor polarizabilities were derived for Rb and Cs. In particular, in order to measure the rare-abundant naturally-occurring radioisotopes, we combined a frequency-doubling system with the diode laser, and a high-resolution UV laser source, up to 100 μW, was obtained. Using the high-resolution experimental setup together with the UV laser source, we succeeded in performing high-resolution nuclear laser spectroscopy of ^<27>Al in the UV region. Hyperfine constants of 4 atomic levels of ^<27>Al, included the ground state, were determined for the first time. Nuclear laser spectroscopy of the rare-abundant naturally-occurring long-lived nucleus ^<176>Lu was performed using the strong optical UV transition, and hyperfine constants of ^<176>Lu and ^<175>Lu were derived and isotope shifts of ^<176-175>Lu were obtained. Some of our results have been reported and most of them will be published elsewhere.