The Dynamics of Ions on Phased Radio-frequency Carpets in High Pressure Gases and Application for Barium Tagging in Xenon Gas Time Projection Chambers

TL;DR

This paper develops new models for ion transport on RF carpets at high pressures, validated against simulations, with applications to barium ion tagging in xenon gas detectors for neutrinoless double beta decay.

Contribution

It introduces analytic and computational methods for modeling RF ion transport in dense gases, including collision effects and ion loss rates, tailored for high-pressure xenon applications.

Findings

Validated models against microscopic simulations.

Identified challenges for operating RF carpets at high pressures.

Provided insights for designing ion transport systems for neutrino experiments.

Abstract

Radio-frequency (RF) carpets with ultra-fine pitches are examined for ion transport in gases at atmospheric pressures and above. We develop new analytic and computational methods for modeling RF ion transport at densities where dynamics are strongly influenced by buffer gas collisions. An analytic description of levitating and sweeping forces from phased arrays is obtained, then thermodynamic and kinetic principles are used to calculate ion loss rates in the presence of collisions. This methodology is validated against detailed microscopic SIMION simulations. We then explore a parameter space of special interest for neutrinoless double beta decay experiments: transport of barium ions in xenon at pressures from 1 to 10 bar. Our computations account for molecular ion formation and pressure dependent mobility as well as finite temperature effects. We discuss the challenges associated with achieving suitable operating conditions, which lie beyond the capabilities of existing devices, using presently available or near-future manufacturing techniques.