Clean materials are required to construct and operate many low-background physics experiments. High-purity copper has found broad use because of its physical properties and availability. In this paper, we describe methods to assay and mitigate 210Pb contamination on copper surfaces, such as from exposure to environmental radon or coming from bulk impurities. We evaluated the efficacy of wet etching on commercial samples and observed that 210Po contamination from the copper bulk does not readily pass into solution. During the etch, the polonium appears to trap at the copper-etchant boundary, such that it is effectively concentrated at the copper surface. We observed a different behavior for 210Pb; high-sensitivity measurements of the alpha emissivity versus time indicate the lowest level of 210Pb contamination ever reported for a commercial copper surface: 0 ± 12 nBq/cm2 (1σ). Additionally, we have demonstrated the effectiveness of mitigating trace 210Pb and 210Po surface backgrounds using custom, high-purity electroplating techniques. These approaches were evaluated utilizing assays performed with an XIA UltraLo-1800 alpha spectrometer.
Bunker, R., et al. "Evaluation and mitigation of trace <sup>210</sup>Pb contamination on copper surfaces." Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 967, no. C, Apr. 2020. https://doi.org/10.1016/j.nima.2020.163870
Bunker, R., Aramaki, T., Arnquist, I. J., Calkins, R., Cooley, J., Hoppe, E. W., Orrell, J. L., & Thommasson, K. S. (2020). Evaluation and mitigation of trace <sup>210</sup>Pb contamination on copper surfaces. Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, 967(C). https://doi.org/10.1016/j.nima.2020.163870
Bunker, R., Aramaki, T., Arnquist, I. J., et al., "Evaluation and mitigation of trace <sup>210</sup>Pb contamination on copper surfaces," Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment 967, no. C (2020), https://doi.org/10.1016/j.nima.2020.163870
@article{osti_1631956,
author = {Bunker, R. and Aramaki, T. and Arnquist, I. J. and Calkins, R. and Cooley, J. and Hoppe, E. W. and Orrell, J. L. and Thommasson, K. S.},
title = {Evaluation and mitigation of trace <sup>210</sup>Pb contamination on copper surfaces},
annote = {Clean materials are required to construct and operate many low-background physics experiments. High-purity copper has found broad use because of its physical properties and availability. In this paper, we describe methods to assay and mitigate 210Pb contamination on copper surfaces, such as from exposure to environmental radon or coming from bulk impurities. We evaluated the efficacy of wet etching on commercial samples and observed that 210Po contamination from the copper bulk does not readily pass into solution. During the etch, the polonium appears to trap at the copper-etchant boundary, such that it is effectively concentrated at the copper surface. We observed a different behavior for 210Pb; high-sensitivity measurements of the alpha emissivity versus time indicate the lowest level of 210Pb contamination ever reported for a commercial copper surface: 0 ± 12 nBq/cm2 (1σ). Additionally, we have demonstrated the effectiveness of mitigating trace 210Pb and 210Po surface backgrounds using custom, high-purity electroplating techniques. These approaches were evaluated utilizing assays performed with an XIA UltraLo-1800 alpha spectrometer.},
doi = {10.1016/j.nima.2020.163870},
url = {https://www.osti.gov/biblio/1631956},
journal = {Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment},
issn = {ISSN 0168-9002},
number = {C},
volume = {967},
place = {United States},
publisher = {Elsevier},
year = {2020},
month = {04}}
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
AC02-76SF00515
OSTI ID:
1631956
Alternate ID(s):
OSTI ID: 1615859 OSTI ID: 1617336
Journal Information:
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Journal Name: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment Journal Issue: C Vol. 967; ISSN 0168-9002
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Journal Article
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Thu Dec 29 23:00:00 EST 2022
· Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
·OSTI ID:1909617