Research

My research focuses on the investigation of the structure and dynamics of rare isotopes which have unusual proton-to-neutron ratios compared to stable nuclei that exist in nature. These exotic nuclei, which can be produced at Facility for Rare Isotope Beams (FRIB), often exhibit surprising phenomena such as nuclear halo characterized by valence neutrons with spatially extended wave functions and shape coexistence with competing nuclear shapes manifested in a single nuclear level. We provide precise and accurate nuclear data from lifetime and spectroscopy experiments and, through comparisons to advanced theory, we aim to understand the forces that bind nucleons into nuclei, test the symmetry in atomic nuclei, answer questions concerning the astrophysical origin of nuclear matter, and address societal needs related to nuclear science. In our experiments, we utilize the combination of the state-of-the-art equipment, including GRETA, TRIPLEX, and S800 spectrograph, to achieve model-independent measurements of excited-state lifetimes.

TRIPLEX plunger device used for lifetime measurements. The combination of the target and degraders along the beam path allows for the application of Doppler-shift techniques, including the recoil-distance method.
 

Biography

Before joining MSU in 2009, I worked at various places in the world; University of Tokyo in Japan, IPN Orsay in France, and University of Cologne in Germany. All these places have accelerator-based facilities on campus, realizing the ideal combination of academic and research environment for scientists and students. In my research activities, I always like to work with early-career scientists (students and postdocs) because I can learn new ideas and views of science by interacting with them. At MSU, FRIB is providing world-class research and training opportunities, and I am looking forward to working with future scientists.

How students can contribute as part of my research team

In my research group, graduate students 1) develop new experimental setup and techniques in spectroscopy and lifetime measurements using relativistic or reaccelerated rare isotopes beams and 2) analyze data and interpret physics results from experiments. Students also work on hands-on projects to operate and improve the TRIPLEX device which is used for lifetime measurements based on Doppler-shift techniques. New detector projects developing radiation-hard diamond detectors and associated data acquisition system are underway. Depending on interest, students also participate in summer projects at various national laboratories to prepare for their future careers.

Scientific publications

• Proton and Neutron Contributions to the Quadrupole Transition Strengths in 39Ca and 39K Studied by Lifetime Measurements of Mirror Transitions, A.Sanchez, H. Iwasaki, et al., Phys. Rev. C110, 024322, (2024).
• Enhanced Electric Dipole Strength for the Weakly Bound States in 27Ne, C. Loelius, N. Kobayashi, H. Iwasaki, et al., Phys. Rev. Lett. 121, 262501 (2018).