https://doi.org/10.1140/epjs/s11734-026-02163-8
Regular Article
Polonium sequestration from copper for dark matter studies using a resin-bound crown ether
1
Department of Chemistry, Queen’s University, K7L 3N6, Kingston, ON, Canada
2
Department of Chemistry and Chemical Engineering, Royal Military College of Canada, K7K 7B4, Kingston, ON, Canada
3
Department of Physics, Engineering Physics and Astronomy, Queen’s University, K7L 3N6, Kingston, ON, Canada
4
SLOWPOKE-2 Facility, Royal Military College of Canada, K7K 7B4, Kingston, ON, Canada
a
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Received:
30
June
2024
Accepted:
27
January
2026
Published online:
18
February
2026
Abstract
The New Experiments With Spheres-Gas (NEWS-G) group has constructed a detector designed to observe the interaction of Weakly Interactive Massive Particles (WIMP) collisions with conventional matter. To detect these potential dark matter interactions, it is necessary to have low background interference. The NEWS-G detector utilizes a 140 cm, 99.99% pure copper sphere within archaeological lead and high-density polyethylene. Against the best efforts of the working group, 222Rn exposure during sphere production and transportation may have caused contamination. Consideration of daughter radionuclides indicates that 210Pb and 210Po, represent the most important background contributors. Although polonium has a favourable standard electrode potential for oxidation, its low concentration favours preferential re-reduction in the presence of copper metal. Thus, a polonium sequestrant has been used to kinetically remove polonium from its solution-metal surface equilibrium. Resin-bound 4,4′(5′)-di-t-butylcyclohexano 18-crown-6 crown ether (or Sr-resin) displays a high affinity for Po4+ at low pH and has been used in this work at a loading of ca. 0.1 g. Etching and sequestrating processes using 5 mL 5.0 M HCl, 150 μL H2O2 and 0.1 g Sr-resin were executed with replicates to determine the efficiency of sequestration through varying deposition methods using 209Po as a surrogate for 210Po. This process has been tested on three different deposition methods, spiking by acidic solutions, electrodepositing, and exposure to a radium source. In these experiments, successful sequestration of 99.6 ± 1.1%, 91 ± 10% and 89 ± 17% of recovered activity was achieved for each exposure method, respectively.
© Crown 2026
