Authors:	Studer, Dominik
Title:	Probing atomic and nuclear structure properties of promethium by laser spectroscopy
Online publication date:	23-Jun-2020
Year of first publication:	2020
Language:	english
Abstract:	Laser resonance ionization is a versatile technique for efficient ion source and sensitive spectroscopy applications, based on step-wise optical excitation of atoms by pulsed laser radiation, with the final step ionizing the atom. This work focuses on in-source spectroscopy applications, i.e. laser probing directly within the ion source environment, and therefore combines the experimental aspects of spectroscopy and ”ion sourcery”. In this context atomic and nuclear structure properties of dysprosium and promethium were determined, with a focus on so far widely unknown parameters of the latter. The results are documented in five publications. They can be thematically separated into atomic and nuclear structure research, performed in broadband and high-resolution laser spectroscopic experiments, respectively. The first part of this thesis aims towards the determination of atomic level energies, efficient resonance ionization pathways and the determination of the first ionization potential. The technique of laser-induced resonant depopulation of excited atomic levels is introduced, offering access to a specific low-lying energy level in Dy. The corresponding ultra-narrow ground-state transition near 1001 nm was located in preparation for high-precision spectroscopy on cold atoms. For the determination of the ionization potential, the techniques of Rydberg-spectroscopy and saddle-point ionization were applied in Dy and Pm, respectively. While the former represents the conventional approach for this task, the sensitivity of the latter was greatly improved and demonstrated in the challenging case of Pm. The extracted values of IP(Dy) = 47 901.76(5) /cm and IP(Pm) = 45 020.8(3) /cm improved the precision of IP(Dy) by one order of magnitude, while IP(Pm) was experimentally determined for the first time. In the second part, dedicated to high-resolution spectroscopic applications, the long-term stability and accuracy of wavelength meters in precision frequency measurement was characterized as an important aspect for the extraction of reliable spectroscopic data. Systematic patterns in deviations of relative frequency measurements were discovered in comparison to complementary devices. Methods to avoid or at least properly consider these effects in data post-processing are discussed. Lastly, the results of high-resolution spectroscopy on long-lived Pm isotopes are presented, using the novel PI-LIST ion source module. The experiment on cyclotron-produced Pm isotopes demonstrates the capabilities of the PI-LIST and represents a further step towards routine operation at on-line radioactive ion beam facilities. The spectroscopic data obtained allowed for the extraction of several nuclear ground state properties of the isotopic sequence of Pm-143 to Pm-147, i.e. magnetic dipole moments, electric quadrupole moments, and changes in mean square charge radii.
DDC:	530 Physik 530 Physics
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 08 Physik, Mathematik u. Informatik
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-4863
URN:	urn:nbn:de:hebis:77-diss-1000036000
Version:	Original work
Publication type:	Dissertation
License:	In Copyright
Information on rights of use:	https://rightsstatements.org/vocab/InC/1.0/
Extent:	viii, 181 Seiten
Appears in collections:	JGU-Publikationen