Sympathetic cooling of trapped Th3+ alpha-recoil ions for laser spectroscopy

Abstract

Sympathetic cooling of Th${}^{3+}$ ions is demonstrated in an experiment where ${}^{229}$Th and ${}^{230}$Th are extracted from uranium recoil ion sources and are confined in a linear Paul trap together with laser-cooled ${}^{88}$Sr${}^{+}$ ions. Because of their similar charge-to-mass ratios the ions are closely coupled and arrange themselves in two-species Coulomb crystals, containing up to a few tens of Th${}^{3+}$ ions. To show the suitability of the sympathetically cooled Th${}^{3+}$ ions for high-resolution laser spectroscopy, the absolute frequencies and isotope shifts of 5F${}_{5/2}$\,$\to$\,6D${}_{5/2}$ and 5F${}_{7/2}$\,$\to$\,6D${}_{5/2}$ transitions of ${}^{230}$Th${}^{3+}$ have been measured. The system is developed for hyperfine spectroscopy of electronic transitions of nuclear ground and isomeric states in ${}^{229}$Th${}^{3+}$.

8 pages, 8 figures

References in corpus (6)

• Direct detection of the 229Th nuclear clock transition
• Observation of the radiative decay of the ${}^{229}\mathrm{Th}$ nuclear clock isomer
• Determination of the extraction efficiency for ${}^{233}$U source $\alpha$-recoil ions from the MLL buffer-gas stopping cell
• Excitation energies, polarizabilities, multipole transition rates, and lifetimes in Th IV
• Coulomb energy contribution to the excitation energy in ${}^{229}$Th and enhanced effect of $\alpha$ variation
• Effects of electrons on nuclear clock transition frequency in ${}^{229}$Th ions

Cited by in corpus (3)

• A continuous-wave vacuum ultraviolet laser for the nuclear clock
• A cryogenic Paul trap for probing the nuclear isomeric excited state ${}^{229\text{m}}$Th${}^{3+}$
• Quantum Sensing Using Atomic Clocks for Nuclear and Particle Physics