Laser cooling and trapping of ${}^{224}$Ra${}^{+}$

Abstract

We report laser cooling and trapping of ${}^{224}$Ra${}^{+}$ ions. This was realized via two-step photoionization loading of radium into an ion trap. A robust source for ${}^{224}$Ra atoms, which have a 3.6-day half-life, was realized with an effusive oven containing ${}^{228}$Th, which has a 1.9-yr half-life, which continuously generates ${}^{224}$Ra via its $\alpha$-decay. We characterized the efficacy of this source and found that after depleting built-up radium the thorium decay provides a continuous source of radium atoms suitable for ion trapping. The vacuum system has been sealed for more than 6 months and continues to trap ions on demand. We also report a measurement of the ${}^{224}$Ra $7s^2{}^1$S${}_0\to 7s7p{}^1$P${}_1$ transition frequency: 621 043 830(60) MHz, which is helpful for efficient photoionization. With this measurement and previous isotope shift measurements we find that the frequency of the same transition in ${}^{226}$Ra is 621 037 830(60) MHz, which disagrees with the most precise measurement, 621 038 489(15) MHz, which is used for the recommended value in the National Institute of Standards and Technology Atomic Spectra Database.

6 pages, 6 figures

References in corpus (8)

• Direct detection of the 229Th nuclear clock transition
• Laser-trapping of Ra-225 and Ra-226 with repumping by room temperature blackbody radiation
• Investigations of Ra${}^{+}$ properties to test possibilities of new optical frequency standards
• Effusive Atomic Oven Nozzle Design Using an Aligned Microcapillary Array
• Radium Ion Optical Clock
• Laser Cooling of Radium Ions
• radioactivedecay: A Python package for radioactive decay calculations
• Absolute frequency measurement of the 7s${}^2$ ${}^1$S${}_0$ $-$ 7s7p ${}^1$P${}_1$ transition in ${}^{225}$Ra

Cited by in corpus (5)

• Lifetimes of the Metastable $6\mathrm{d}{}^2{\mathrm{D}}_{5/2}$ and $6\mathrm{d}{}^2{\mathrm{D}}_{3/2}$ States of Ra${}^{+}$
• Spectroscopy of electric dipole and quadrupole transitions in ${}^{224}$Ra${}^{+}$
• Laser Cooling and Hyperfine Measurements of Radium-225 Ions
• Radioactive Molecules as Laboratories of Fundamental Physics
• Application of the Variational R-matrix Method for the Dirac Equation to the Be Atom