First Demonstration of Mass Measurements for Exotic Nuclei Using Rare-RI Ring

Abstract

The Rare-RI Ring is an isochronous storage ring at the RI Beam Factory of RIKEN. Its mission is measuring masses of most neutron-rich nuclei relevant for r-process nucleosynthesis. The Rare-RI Ring is based on the isochronous mass spectrometry technique to achieve mass measurement with a precision of 10 −6 in less than 1-ms measurement time. A demonstration of mass measurements of 79 As, 77 Ga, 76 Zn, and 75 Cu, whose masses are well known is presented. The Rare-RI Ring is now ready to start its mission of measuring masses of rare isotopes.

First Application of Mass Measurements with the Rare-RI Ring Reveals the Solar r -Process Abundance Trend at A=122 and A=123Li1, Naimi2, Sprouse3 et al. 2022Phys. Rev. Lett.20110View full textAdd to dashboardCite

“…This Letter reports precision mass measurements of neutron-rich nuclei produced at the Radioactive Isotope Beam Factory (RIBF) and their implication in the production of r-process elements with atomic mass number A = 122 and A = 123. Mass measurements of nuclei with neutron number N = 77 were performed for the first time with a new type of mass spectrometer, namely the Rare-RI Ring (R3), recently commissioned at the RIBF/RIKEN facility [13]. We examine the implication of the 123 Pd mass on the abundance calculation for conditions representing a neutron star merger event.…”

Development and operation of an electrostatic time-of-flight detector for the Rare RI storage Ring

“…In 2016, the first demonstration of a mass measurement was performed using exotic nuclei with well-known masses around 78 Ge [37]. Exotic nuclei were obtained from the in-flight fission of a 238 U relativistic primary beam with an energy of 345 MeV/u on a 10-mm-thick 9 Be target.…”

First application of mass measurement with the Rare-RI Ring reveals the solar r-process abundance trend at A=122 and A=123

“…This Letter reports precision mass measurements of neutron-rich nuclei produced at the Radioactive Isotope Beam Factory (RIBF) and their implication in the production of r-process elements with atomic mass number A=122 and A=123. Mass measurements of nuclei with neutron number N=77 were performed for the first time with a new type of mass spectrometer, namely the Rare-RI Ring (R3), recently commissioned at the RIBF/RIKEN facility [12]. We examine the implication of the 123 Pd mass on the abundance calculation for a neutron star merger event.…”

“…Finally, particles were stopped in the NaI scintillator detector placed behind the IC at ELC. The mass-to-charge ratio (m/q) of the particle of interest with a revolution time T is determined relative to a reference particle with m 0 /q 0 and T 0 by using the following formula [12,17]:…”

“…Additional systematic uncertainties, σ sys , due to the determination of parameters such as Length 3S0 , T OF of f set and T 0 were estimated and reported in Table I. Details of data analysis method can be found in references [12,18]. The full data analysis method as well as the details of estimating the systematic uncertainties will be reported in a subsequent publication.…”