Mass measurements of neutron-rich isotopes near N = 20 by in-trap decay with the ISOLTRAP spectrometer

The masses of $^{34}\mathrm{Si}$, $^{33,34}\mathrm{Mg}$, and $^{34}\mathrm{Al}$ have been measured with the ISOLTRAP Penning-trap spectrometer at ISOLDE/CERN. The results are in agreement with previous mass measurements and uncertainties have been decreased. The mass of $^{34}\mathrm{Al}$ was determined in two configurations, one following direct production by the ISOLDE facility, favoring the ${4}^{\ensuremath{-}}$ state, expected to be the ground state, second by in-trap decay of $^{34}\mathrm{Mg}$, followed by recoil-ion trapping, favoring the production of the isomeric ${1}^{+}$ state. A position-sensitive detector was used to clean the ToF-ICR resonance. In addition, the mass of the refractory doubly magic $^{34}\mathrm{Si}$ nucleus was directly measured, using the in-trap decay of $^{34}\mathrm{Mg}$, following two sequential recoil-ion captures. The approach, challenges and conclusions are discussed.