Inline cryogenically cooled radio-frequency ion trap as a universal injector for cold ions into an electrostatic ion-beam storage ring: Probing and modeling the dynamics of rotational cooling of OH

H. B. Pedersen*, H. Juul, F. K. Mikkelsen, A. P. Rasmussen, L. H. Andersen

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Abstract

We describe the setup and characterization of a cryogenic multipole radio-frequency (RF) ion trap that enables the accumulation and cooling of mass-selected ions before injection into the SAPHIRA storage ring. To characterize the RF trap setup, we use OH- anions and explore the threshold photodetachment cross section measured after storage in SAPHIRA as a probe of the rotational temperature. Beyond the temperature of the ion trap assembly, cooled to 6 K, the final rotational temperature of the OH- ions is strongly influenced by the density of cooled He and the actual number of trapped ions while much less affected (possibly unaffected) by the time-varying field of the trap. To obtain rotationally cold OH- ions, the RF trap must be operated with low He density and a low number of ions. High He densities, corresponding to a strong coupling of the trapped ions and He gas, lead to a significant rotational heating of the trapped ion ensemble, and the He density seems to limit the actual reachable rotational temperature. We demonstrate that cold ions in the RF trap remain cold for at least 30 ms in the SAPHIRA (300 K) storage ring at a base pressure of ∼8×10-9mbar.

Original languageEnglish
Article number053111
JournalPhysical Review A
Volume106
Issue5
Number of pages23
ISSN2469-9926
DOIs
Publication statusPublished - Nov 2022

Fingerprint

Dive into the research topics of 'Inline cryogenically cooled radio-frequency ion trap as a universal injector for cold ions into an electrostatic ion-beam storage ring: Probing and modeling the dynamics of rotational cooling of OH'. Together they form a unique fingerprint.

Cite this