An ultralow-noise superconducting radio-frequency ion trap for frequency metrology with highly charged ions

TL;DR

This paper introduces a superconducting RF ion trap with ultralow noise and high quality factor, designed to improve frequency metrology accuracy for highly charged ions by reducing motional heating and frequency shifts.

Contribution

The paper presents a novel superconducting RF ion trap combining an RF cavity and linear Paul trap, achieving high Q at cryogenic temperatures for enhanced frequency metrology.

Findings

RF quadrupole mode at 34.52 MHz with Q≈2.3×10^5 at 4.1 K

Successful trapping of ${}^9 ext{Be}^+$ Coulomb crystals

Proof-of-principle operation as a quadrupole mass filter with highly charged ions

Abstract

We present a novel ultrastable superconducting radio-frequency (RF) ion trap realized as a combination of an RF cavity and a linear Paul trap. Its RF quadrupole mode at 34.52 MHz reaches a quality factor of $Q\approx2.3\times 10^5$ at a temperature of 4.1 K and is used to radially confine ions in an ultralow-noise pseudopotential. This concept is expected to strongly suppress motional heating rates and related frequency shifts which limit the ultimate accuracy achieved in advanced ion traps for frequency metrology. Running with its low-vibration cryogenic cooling system, electron beam ion trap and deceleration beamline supplying highly charged ions (HCI), the superconducting trap offers ideal conditions for optical frequency metrology with ionic species. We report its proof-of-principle operation as a quadrupole mass filter with HCI, and trapping of Doppler-cooled ${}^9\text{Be}^+$ Coulomb crystals.