Mass Measurements of Neutron-Deficient Yb Isotopes and Nuclear Structure at the Extreme Proton-Rich Side of the N=82 Shell.

Sönke Beck,Ish Mukul,Michael Vansteenkiste,Jie Yang,Michael E Wieser,Andrew Jacobs,E Leistenschneider ,V Monier ,C Andreoiu ,T Brunner ,J Flowerdew ,R I Thompson ,A Gaamouci ,R Klawitter ,D Curien ,C Scheidenberger ,E M Lykiardopoulou ,E Dunling ,I Dedes ,A A Kwiatkowski ,W R Plaß ,M P Reiter ,Hualei Wang ,G Gwinner ,S F Paul ,B Kootte ,J Dudek ,J Dilling ,C Will ,N Minkov ,J Bergmann ,L Graham ,Y Lan ,J L Tracy ,T Dickel

doi:10.1103/physrevlett.127.112501

Abstract

High-accuracy mass measurements of neutron-deficient Yb isotopes have been performed at TRIUMF using TITAN's multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). For the first time, an MR-TOF-MS was used on line simultaneously as an isobar separator and as a mass spectrometer, extending the measurements to two isotopes further away from stability than otherwise possible. The ground state masses of ^{150,153}Yb and the excitation energy of ^{151}Yb^{m} were measured for the first time. As a result, the persistence of the N=82 shell with almost unmodified shell gap energies is established up to the proton drip line. Furthermore, the puzzling systematics of the h_{11/2}-excited isomeric states of the N=81 isotones are unraveled using state-of-the-art mean field calculations.

Highlights

Mass Measurements of Neutron-Deficient Yb Isotopes and Nuclear Structure at the Extreme Proton-Rich Side of the N = 82 Shell
An MR-TOF-MS was used on line simultaneously as an isobar separator and as a mass spectrometer, extending the measurements to two isotopes further away from stability than otherwise possible
Extending experimental data toward the drip lines is decisive for testing prediction capacities of theories, estimating the model uncertainties and for improving models and theories [3]

Summary

Published by the American Physical Society

Neutron drip lines; shells can weaken or disappear, and new magic numbers appear [4,5]. A novel method for mass separation in an MR-TOF-MS is the dynamical retrapping of the ions in the injection trap after the TOF dispersion procedure [40]. In which the isobaric contamination was too high to observe Yb ions, the MR-TOF-MS was first used as an isobar separator: after TOF dispersion of the ions in the analyzer, the ions of interest were retrapped in the injection trap. They were recooled and injected again into the analyzer for the subsequent mass measurement procedure. The retrapping increases the dynamic range of the measurement to 5 orders of magnitude, a value which is rarely achieved in

Retrapping on

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This work