Trapping of triply charged thorium-229 for a nuclear clock

Abstract

We developed an ion trap system for triply charged thorium-229 (229Th3+). We used uranium-233 as the ion source, which supplied 229Th3+ ions in the nuclear ground state and low-lying isomeric state (229mTh3+) at 8.3 eV. Our ion trap system allows the laser spectroscopy of 229mTh3+ toward the nuclear clock.