Helium-3, writes David Kramer, “occurs at a ratio of 0.2 parts per million of 4He.” However, according to the International Union of Pure and Applied Chemistry, 1 the natural abundance of 3He is 1.37 ppm. Otherwise, the article was excellent.
REFERENCE
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R. K.
Harris
et al, Pure Appl. Chem.
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), available at http://www.iupac.org/publications/pac/2001/pdf/7311x1795.pdf.© 2010 American Institute of Physics.
2010
American Institute of Physics
