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 Pb-210 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 Po-210 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 Pb-210; high-sensitivity measurements of the alpha emissivity versus time indicate the lowest level of Pb-210 contamination ever reported for a commercial copper surface: 0 +/- 12 nBq/cm2 (1-sigma). Additionally, we have demonstrated the effectiveness of mitigating trace Pb-210 and Po-210 surface backgrounds using custom, high-purity electroplating techniques. These approaches were evaluated utilizing assays performed with an XIA UltraLo-1800 alpha spectrometer.
Bunker, Raymond A., et al. "Evaluation and mitigation of trace 210Pb contamination on copper surfaces." Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 967, Jul. 2020. https://doi.org/10.1016/j.nima.2020.163870
Bunker, Raymond A., Aramaki, T, Arnquist, Isaac J., Calkins, R, Cooley, J, Hoppe, Eric W., Orrell, John L., & Thommasson, Kimbrelle S. (2020). Evaluation and mitigation of trace 210Pb contamination on copper surfaces. Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, 967. https://doi.org/10.1016/j.nima.2020.163870
Bunker, Raymond A., Aramaki, T, Arnquist, Isaac J., et al., "Evaluation and mitigation of trace 210Pb contamination on copper surfaces," Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment 967 (2020), https://doi.org/10.1016/j.nima.2020.163870
@article{osti_1617336,
author = {Bunker, Raymond A. and Aramaki, T and Arnquist, Isaac J. and Calkins, R and Cooley, J and Hoppe, Eric W. and Orrell, John L. and Thommasson, Kimbrelle S.},
title = {Evaluation and mitigation of trace 210Pb 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 Pb-210 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 Po-210 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 Pb-210; high-sensitivity measurements of the alpha emissivity versus time indicate the lowest level of Pb-210 contamination ever reported for a commercial copper surface: 0 +/- 12 nBq/cm2 (1-sigma). Additionally, we have demonstrated the effectiveness of mitigating trace Pb-210 and Po-210 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/1617336},
journal = {Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment},
volume = {967},
place = {United States},
year = {2020},
month = {07}}
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC05-76RL01830
OSTI ID:
1617336
Report Number(s):
PNNL--SA-151382
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 Vol. 967
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 884https://doi.org/10.1016/j.nima.2017.12.015
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 880https://doi.org/10.1016/j.nima.2017.10.054
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 764https://doi.org/10.1016/j.nima.2014.06.082
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 828https://doi.org/10.1016/j.nima.2016.04.070
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 775https://doi.org/10.1016/j.nima.2014.11.052
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 676https://doi.org/10.1016/j.nima.2011.12.043
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 579, Issue 1https://doi.org/10.1016/j.nima.2007.04.101
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 551, Issue 2-3https://doi.org/10.1016/j.nima.2005.05.068
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 591, Issue 3https://doi.org/10.1016/j.nima.2008.03.001
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 506, Issue 3https://doi.org/10.1016/S0168-9002(03)01368-8