Speaker
Description
High-precision mass measurements of radioactive isotopes play a key role in advancing our understanding of nuclear structure and nuclear astrophysics. Nuclear masses provide direct access to binding energies and are essential inputs for testing nuclear models and studying shell evolution far from stability [1]. One area of interest is the rare-earth abundance peak around A = 165, which hints at a sub-shell closure or a change in nuclear structure [2].
The IGISOL (Ion Guide Isotope Separator On-Line) facility [3] in Jyväskylä provides a versatile approach to produce exotic nuclei. Reaction products from fusion, fission, or multi-nucleon transfer reactions are stopped in a gas cell, extracted, bunched and delivered to various experimental setups. The JYFLTRAP double Penning-trap mass spectrometer [4], located downstream of IGISOL, is dedicated to high-precision mass measurements. It combines a purification trap for isobaric cleaning with a precision trap where cyclotron frequencies are measured using time-of-flight ion-cyclotron-resonance [5] and phase-imaging techniques [6].
In this contribution, I present recent developments of the IGISOL facility and results of the JYFLTRAP setup at IGISOL, such as the mass measurement of neutron-rich barium isotopes with A = 146 - 151. Theoretical models predict strong structural changes including quadrupolar and octupolar deformation in this region [7]. The results of these measurements will be employed to investigate the effects of these deformations on the binding energies, benchmark nuclear models and constrain r-process simulations.
[1] M. Mumpower, et al., Prog. in Part. and Nucl. Phys. 86, 86–126 (2016).
[2] M. R. Mumpower, et al., Phys. Rev. C 85, 045801 (2012)
[3] I.D. Moore et al., Nucl. Inst. Meth. Phys. Res. B 317 (2013) 208.
[4] T. Eronen et al., European Physical Journal A 48, 46 (2012).
[5] König et al., Int. J. Mass Spectrom. Ion Process. 142, 95 (1995).
[6] D.A. Nesterenko et al., Eur. Phys. J. A 54, 154 (2018).
[7] Y. Cao et al., Phys. Rev. C 102, 024311 (2020).