Speaker
Description
Nuclear mass plays an essential role in the understanding of the r-process which is responsible for the synthesis of about one-half of elements heavier than iron up to bismuth and all of thorium and uranium. The nuclei around the doubly magic numbers N=50, N=82 and N=126 are believed to be waiting points were matter accumulate and therefore form the major peaks in the r-process abundance. Sensitivity studies for the r-process have indicated that masses of neutron-rich nuclei in those regions have a significant impact on the final elemental abundance pattern. The binding energy deduced directly from nuclear masses of these nuclei can also be a sensitive probe of the structure of these nuclei.
Rare-RI ring (R3) is an isochronous mass spectrometer at RIBF in RIKEN. It aims at measuring the mass of exotic nuclei with a precision of 10-6 within less than 1ms. Thus, we can measure the mass of exotic nuclei with very short half-lives and low production yields.
In this contribution, we report on the first mass measurement campaign at R3 conducted in the Autumn of 2018. The masses of 74,76Ni in the N=50, Z =28 region which is related to the weak r-process nucleosynthesis were measured. The mass of 122Rh, 123,124Pd and 125Ag isotopes in the southwestern of N=82, Z= 50 region which are relevant for the main r-process nucleosynthesis were also measured.
