This work will deploy ion trapping techniques (in which electric fields are used to grab onto and hold an atom which has a missing electron) to an unusually heavy, and radioactive, atom: radium. This atom is particularly important for the study of the conditions in the early universe. Part of the reason is that it contains a deformed nucleus, specifically one with a pear shape, which makes it more sensitive to some effects than lighter elements with a more round nucleus. Because radium is radioactive, however, it is challenging to study. This work addresses this challenge by using a small radium sample in an experiment in which lasers are used to cool and trap radium ions and hold them for extended periods of time to study. This work will produce the first measurements of some basic properties of the radium ion. It will also create and study molecular ions that contain radium. This work will improve understanding of the element and its potential to address long-standing physics questions.
In this project the PI and his colleagues aim to make first measurements of basic radium ion properties and study radium-based molecular ions. For the radium ion they will measure the branching fractions of the 7P_3/2 state, the lifetimes of the 7P_1/2, 7P_3/2, 6D_3/2, and 6D_5/2 states. Besides a lower bound on the 6D_5/2 lifetime none of these values have been previously measured. The values are important for a basic understanding of the radium ion, and essential for advanced work, such as parity nonconservation measurements. The group will further study radium-based molecular ions, such as RaOH+, which are promising for studying charge-parity violation. They plan to create the molecular ions in the ion trap, sympathetically cool them with co-trapped Ra+, and then probe the molecular ions with photodissociation spectroscopy to provide a basic understanding of their energy level structure.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
