"Chasing Zero": a glimpse into the world of low-background nuclear measurements

Invited  · Invited

Abstract

How do you measure radioactivity when the signal you’re interested in is far smaller than the natural background radiation all around us? This talk offers a virtual excursion through Pacific Northwest National Laboratory’s Shallow Underground Laboratory (SUL), a cleanroom facility where shielding and carefully selected materials enable extremely sensitive nuclear measurements.

This talk begins by looking at how PNNL scientists produce exceptionally radiopure copper, why detector materials matter, and how low-background radiation detectors are assembled and operated in the SUL.

Lastly, the story concludes with a demonstration of how this low-background methodology connects to real-world impact: using argon-39 (³⁹Ar) to determine groundwater residence times, and detecting argon-37 (³⁷Ar) for treaty verification.

–

Publication: 1) C. E. Aalseth, R. M. Bonicalzi, M. G. Cantaloub, A. R. Day, L. E. Erikson, J. Fast, J. B. Forrester, E. S. Fuller, B. D. Glasgow, L. R. Greenwood, E. W. Hoppe, T. W. Hossbach, B. J. Hyronimus, M. E. Keillor, E. K. Mace, J. I. McIntyre, J. H. Merriman, A. W. Myers, C. T. Overman, N. R. Overman, M. E. Panisko, A. Seifert, G. A. Warren, R. C. Runkle; A shallow underground laboratory for low-background radiation measurements and materials development. Rev. Sci. Instrum. 1 November 2012; 83 (11): 113503. https://doi.org/10.1063/1.4761923
2) Aalseth, C.E., et al., Measurement of 37Ar to support technology for On-Site Inspection under the Comprehensive Nuclear-Test-BanTreaty. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2011. 652(1): p. 58–61. DOI: 10.1016/j.nima.2010.09.135.
3) Mace, E., et al., Methods for using argon-39 to age-date groundwater using ultra-low-background proportional counting. Appl Radiat Isot, 2017. 126: p. 9–12. DOI: 10.1016/j.apradiso.2016.12.037.

Presenters

  • Emily Mace

    • Pacific Northwest National Laboratory (PNNL)

Authors

  • Emily Mace

    • Pacific Northwest National Laboratory (PNNL)