Japanese team achieves high-precision mass measurements of argon isotopes, revealing variations in the strength of the new magic number N=32
An international collaborative research team comprising RIKEN and the High Energy Accelerator Research Organization (KEK), among others, conducted high-precision mass measurements of short-lived argon isotopes far from the line of nuclear stability, using the superconducting RI beam generation and separation device BigRIPS at the RI Beam Factory (RIBF) of RIKEN Nishina Center for Accelerator-Based Science, as well as the CRISMASS system, a stationary slow radioactive isotope precision mass spectrometer jointly developed by the two institutions. The research team directly measured the mass of argon-50 (^50Ar, 18 protons, 32 neutrons) for the first time, and improved the mass measurement precision of argon-49 (^49Ar) by approximately 250-fold compared to previous measurements, providing insights into the energy of the two-neutron shell gap near the new magic number N=32. The results have been...
2026-08-31
