Description:

Abstract:

The nuclear isomeric first excited state of Thorium-229 has drawn attention from many fields. In general, nuclei are insensitive to ambient disturbance due to the shielding by their core electrons. In addition, the extraordinary-low energy level of Th-229 can be accessed by laser spectroscopy techniques. Since its insensitiveness can enable us to achieve longer decoherence time in comparison to atomic states, it attracts much interest from atomic clock, fundamental physics, and other fields. However current large energy uncertainty makes the laser spectroscopy difficult. On the contrary, optical transition between the isomer state and the ground state has not been observed yet.

We recently succeeded in pumping up Th-229 nuclei from the ground state to the isomer state by nuclear resonant scattering (NRS) with synchrotron radiation X-ray beam. This method enables us to observe and spectroscopy of the following VUV photon emission; therefore, that is a key technique to determine the energy of the isomer precisely. We also determined several nuclear parameters which are related to the Th-229 isomeric state. In this talk, the detail of the NRS measurement and the current status of the following VUV photon measurement are presented.

Speaker: Takahiko Masuda, Research Institute for Interdisciplinary Science, Okayama University, Japan

Keywords: Physics, Center for Fundamental Physics, CFP