Work

Trapping and sympathetic cooling of Th3+ ions in a linear ion trap

Year: 2025

Type: article

Abstract: We demonstrate a modified integration of a linear ion trap with a time-of-flight mass spectrometer optimized to enhance the loading and detection of Th3+ ions. A phase-locked radiofrequency/high-voltage switch incorporating zero-crossing triggering and a programmable time delay is a key upgrade to minimize RF phase-dependent jitter and enable the unambiguous identification of Th3+ ions. To enhance purity, yield, and lifetime of trapped Th3+ ions, we optimize the ion loading parameters, including ion trap settings (RF amplitude, endcap voltages, and loading time), laser-ablation pulse energy, helium partial pressure, and ion storage time. These improvements extend trapping lifetimes of Th3+ ions to several hundred seconds, representing an order-of-magnitude increase compared to our previous work. Finally, single-pulse ablation of mixed Sr–Th nitrate targets enables the direct co-loading of Th3+ and 88Sr+ ions, and subsequent laser cooling forms multi-component Coulomb crystals for laser spectroscopy of Th3+ ions. Given the long trapping lifetime of Th3+ ions, this system will serve as a platform for developing a prototype trap-based thorium nuclear clock.

Source: Journal of Applied Physics

DOI: 10.1063/5.0300192

Authors: Zi Li, Wen-Ting Gan, Chen Wang, Lin Li, Xia Hua, Xin Tong

Institutions: University of Chinese Academy of Sciences, Innovation Academy for Precision Measurement Science and Technology, CAS, Wuhan Institute of Quantum Technology

Language: English

Topic: Advanced Frequency and Time Standards

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,500

Funders: National Natural Science Foundation of China, Chinese Academy of Sciences