Speaker
Description
To reveal the origin of heavy-element synthesis in the universe, studying nuclear properties such as half-life, atomic mass, and nuclear structure is essential. Particularly, the properties of heavy-element nuclei located in unreachable regions, specifically those in the vicinity of the neutron magic number N = 126 and neutron-rich actinide nuclei, are crucial for understanding the r-process. For this purpose, we installed the KEK Isotope Separation System (KISS) [1,2], which produces these nuclei using multi-nucleon transfer reactions [3]. We have studied the nuclear properties through beta-decay spectroscopy, precise mass measurement using multi-reflection time-of-flight mass spectrometry (MRTOF-MS), and laser spectroscopy.
To advance these studies, we upgraded KISS to KISS-1.5 [4], which introduces a new concept of no separation and simultaneous measurements, facilitated by particle identification using MRTOF-MS. I will present the details of the KISS-1.5 equipment, which consists of a helium gas cell, MRTOF-MS, and a variable mass range separator capable of transporting multiple nuclei with different mass numbers.
References:
[1] Y. Hirayama, et al., Nucl. Instrum. Methods B 353 (2015) 4-15.
[2] Y. Hrayama, et al., Nucl. Instrum. Methods B 412 (2017) 11-18.
[3] Y.X. Watanabe, et al., Phys. Rev. Lett. 115 (2015) 172503.
[4] Y.X. Watanabe, et al., Nucl. Phys. A 1061 (2025) 123140.
