Atomic masses of intermediate-mass neutron-deficient nuclei with relative uncertainty down to 35-ppb via multireflection time-of-flight mass spectrograph

Abstract

High-precision mass measurements of Cu63, Zn64−66, Ga65, Ge65−67, As67, Br78,81, Rb80, and Sr79 were performed utilizing a multireflection time-of-flight mass spectrograph combined with the gas-filled recoil ion separator GARIS-II. In the case of Ga65, a mass uncertainty of 2.1keV, corresponding to a relative precision of δm/m=3.5×10−8, was obtained and the mass value is in excellent agreement with the 2016 Atomic Mass Evaluation. For Ge67 and Br81, where masses were previously deduced through indirect measurements, discrepancies with literature values were found. The feasibility of using this device for mass measurements of more neutron-deficient nuclei, which have significant impact on the rp-process pathway, is discussed.