Development of an electrodynamic balance to study single levitated particles exposed to alkali-metal vapor
arXiv:2605.14618 · doi:10.1016/j.jaerosci.2026.106862
The paper describes a newly built electrodynamic balance that can trap single particles while exposing them to alkali‑metal vapor, and shows that ultraviolet‑irradiated particles change their charge‑to‑mass ratio after such exposure.
Abstract
Electrodynamic balances (EDBs) have been widely used to investigate reactions between levitated particles and background gases. In this paper, we report the development of an EDB that exposes trapped particles to alkali-metal vapor. The apparatus was developed principally to investigate the interactions between such vapor and the paraffin used as a spin anti-relaxation coating for alkali-metal vapor cells by atomic physicists. The trap electrodes of the EDB were installed in a vacuum glass cell. Particles were loaded via laser launching, without venting or contaminating the cell. Alkali-metal vapor was released from a dedicated dispenser. We found changes in the charge-to-mass ratios of trapped particles irradiated with ultraviolet light after exposure to alkali-metal vapor. These results demonstrate the utility of the apparatus.
26 pages, 9 figures. Journal-accepted manuscript. Minor typo in Fig. 8 caption: "5 Pa" should be "0.5 Pa"