Development of the Photo-Resonance Excitation and Cavity Ionization Spectroscopy Apparatus (PRECIOSA)*

Collinear resonance ionization laser spectroscopy has proven an important tool for studying the properties of short-lived nuclei away from stability such as nuclear spins, electromagnetic moments and changes in the nuclear root-mean-square charge radii. In order to simultaneously achieve a high efficiency and precision, the ion beams used for such studies are often cooled down and bunched in gas filled radio-frequency ion traps. However, this approach is unsuitable for many species of interest, such as highly reactive ones or those with isotopes with lifetimes shorter (<5 ms) than the typical trapping times. In this contribution, I will present the developments of a highly sensitive experimental scheme to overcome these challenges.

The key idea is based on performing a stepwise resonant ionization process, with the ionization step laser obtained from a large-mode, high-power cavity, directed perpendicular to the trajectory of the atomic beam [1]. This will allow a localized ionization volume (<5 mm diameter) from which the electrons can be extracted and detected in coincidence with the produced ions. This will facilitate a virtually background-free measurement, while allowing the time and position information of the resulting ions and electrons to be extracted. A Doppler correction can then be applied to the atoms on an event-by-event basis, allowing for precise measurements of the transitions of interest, regardless of the initial energy distribution . These developments are expected to enable laser spectroscopy measurements of short-lived isotopes created with large energy spreads, lifetimes less than1 ms and production yields of less than 1 ion per minute. The current status of the proposed experiment, preliminary results obtained on stable isotopes, as well as future research directions will be discussed.

1. S. M. Udrescu, D. A. Torres, and R. F. Garcia Ruiz, Phys. Rev. Research 6, 013128 (2024)