Electric charging effects on insulating surfaces in cryogenic liquids

Abstract

This paper presents a new technique to study the adsorption and desorption of ions and electrons on insulating surfaces in the presence of strong electric fields in cryoliquids. The experimental design consists of a compact cryostat coupled with a sensitive electro-optical Kerr device to monitor the stability of the electric fields. The behavior of nitrogen and helium ions on a poly(methyl methacrylate) (PMMA) surface was compared to a PMMA surface coated with a mixture of deuterated polystyrene and deuterated polybutadiene. Ion accumulation and removal on these surfaces were unambiguously observed. Within the precision of the data, both surfaces behave similarly for the physisorbed ions. The setup was also used to measure the (quasi-)static dielectric constant of PMMA at T ≈ 70 K. The impact of the ion adsorption on the search for a neutron permanent electric dipole moment in a cryogenic environment, such as the nEDM@SNS experiment, is discussed.

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Acknowledgement

The authors want to thank the individuals at the University of Kentucky who took shifts and gave up time on weekends to help collect data. Special thanks go to Ritwika Chakraborty. The authors would also like to thank Robert Golub, Mike Hayden, and Steve Lamoreaux for their discussion and useful suggestions. This work would not have been possible without the generous funding from the Office of Nuclear Physics of the DOE Office of Science, Grant Nos. DE-SC0014622 and DE-ACOS-00OR22725.

Contributions

Wolfgang Korsch: Conceptualization (lead); Data curation (equal); Formal analysis (lead); Investigation (lead); Methodology (lead); Software (equal); Supervision (lead); Validation (equal); Visualization (equal); Writing – original draft (equal); Writing – review & editing (lead). Mark Broering: Data curation (equal); Investigation (equal); Methodology (supporting); Software (equal); Writing – original draft (equal). Ashok Timsina: Data curation (equal); Investigation (equal); Methodology (supporting); Software (supporting). Kent K.H. Leung: Investigation (supporting); Writing – original draft (supporting); Writing – review & editing (supporting). Joshua Abney: Conceptualization (supporting); Methodology (supporting); Software (supporting). Dmitry Budker: Conceptualization (supporting); Writing – review & editing (supporting). Bradley W. Filippone: Investigation (supporting); Writing – review & editing (supporting). Jiachen He: Investigation (supporting). Suman Kandu: Investigation (supporting). Mark McCrea: Investigation (supporting). Murchhana Roy: Investigation (supporting); Writing – review & editing (supporting). Christopher Swank: Investigation (supporting). Weijun Yao: Conceptualization (equal); Investigation (equal).

Data Availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Conflict of Interest

The authors have no conflicts to disclose.

Files

Embargoed

The files will be made publicly available on April 1, 2025.

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