Development of an electrodynamic balance to study single levitated particles exposed to alkali-metal vapor

TL;DR

This paper presents a new electrodynamic balance capable of studying interactions between levitated particles and alkali-metal vapor, enabling detailed investigation of surface reactions and charge changes.

Contribution

The development of an EDB that exposes levitated particles to alkali-metal vapor, with a novel design allowing laser loading and vapor exposure without contamination.

Findings

Charge-to-mass ratios of particles changed after vapor exposure.

The apparatus successfully exposed particles to alkali-metal vapor.

Demonstrated utility for studying vapor-particle interactions.

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.