Seminarium Fizyki Jądra Atomowego

Laser spectroscopy studies provide charge radii, spins and nuclear moments, key ingredients to test and validate nuclear models. To perform laser spectroscopy on heavy exotic nuclides, the highest efficiencies in combination with a high spectral resolution are required. In this contribution we report on recent results for the neutron-deficient mercury and actinium isotopes obtained using in-source spectroscopy at the ISOLDE/CERN (CH) and in-gas jet spectroscopy at the LISOL (B) facilities respectively. In the neutron-deficient mercury isotopes measurements of the charge radii show that the so-called shape staggering observed already four decades ago [1], is a local phenomena and confirms the interpretation in terms of shape-coexistence in the mercury isotopes around N=104. Monte Carlo Shell-Model calculations were performed by the Tokyo group and are in good agreement with the experimental data. The in-source technique used at ISOLDE suffers from limited spectral resolution. In order to improve this, in-gas jet laser ionization spectroscopy was developed [2,3] and applied to study the neutron deficient actinium isotopes including the N=126 215Ac (T1/2=0.17 s) isotope. The obtained magnetic moments are reproduced by large-scale shell model calculations confirming the stability of the N=126 neutron shell closure. By exploring the physical and technical limits of the in-gas jet laser ionization spectroscopy approach [2] at the newly commissioned laser laboratory at KU Leuven, the best performance in spectral resolution and ionization efficiency necessary for connecting to the Superconducting Separator Spectrometer (S3 - GANIL) can be obtained [4]. The reach of this novel approach to study the atomic and nuclear physics properties of the heaviest elements will be discussed.

[1] Bonn,- PLB 38 (1972)
[2] Kudryavtsev,- NIM 297 (2013) 7
[3] Ferrer,- Nature Comm. (2017)
[4] Ferrer,- NIMB317 (2014)