Laser Spectroscopy of Actinides: Octupole Deformation and Gas-Jet Characterization

Elise Verstraelen her PhD thesis reports on a laser spectroscopy study in the actinide region and covers three main topics. Firstly, the results on in-source resonance-ionization spectroscopy of the neutron-rich actinium isotopes 225-229Ac are detailed. These measurements were performed at the TRIUMF ISAC facility in Vancouver and resulted in new data on the changes in mean-square charge radii and the magnetic dipole moments of isotopes 226,228,229Ac, which lie in one of the regions of the nuclear chart with presumed octupole deformation. In these measurements, the attained spectral resolution did not allow to resolve the full hyperfine structure. Secondly, the in-gas-jet laser spectroscopy method, which is one of the techniques that be applied to measure the (trans)actinides with an improved spectral resolution, has been characterized. An in-depth characterization of the flow properties of a Mach-8.5 de Laval nozzle, designed at the Von Karman Institute for Fluid Dynamics, is presented. Using the well-established Planar Laser-Induced Fluorescence (PLIF) as well as the recently presented and validated Planar Laser-Induced Fluorescence Spectroscopy (PLIFS) technique, relative-density profiles and hyperfine spectra of copper were measured to validate the achievable spectral resolution prior to the utilization in i.a. on-line in-gas-jet resonance ionization spectroscopy of nobelium at the SHIP set-up at GSI. Finally, the initial commissioning of a new laser laboratory (IGLIS II) is presented with the aim to identify and characterize new, efficient laser ionization schemes with particular sensitivities to determine the nuclear observables, that can be compared with atomic theory calculations and used during i.a. on-line in-gas-jet laser-spectroscopy experiments at the S3 Low Energy Branch (LEB) facility at GANIL, France.

Publication year:2021

Accessibility:Open