About the Authors

Carl A. Whitfield

carl.whitfield@physics.org

Current address: Department of Physics, University of Warwick, Coventry, United Kingdom, CV3 7AL

Affiliation Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom, S3 7RH

Rhoda J. Hawkins

Affiliation Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom, S3 7RH

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceptualization: RJH. Data curation: CAW. Formal analysis: CAW. Funding acquisition: RJH. Investigation: CAW. Methodology: CAW RJH. Project administration: RJH. Resources: RJH. Software: CAW. Supervision: RJH. Validation: CAW RJH. Visualization: CAW. Writing – original draft: CAW. Writing – review & editing: CAW RJH.