FECYT - Spanish Foundation for Science and Technology
Caption: The black chips represent the quantity of a chemical element with natural isotopic abundance whereas the blue and green chips indicate the quantity of the same element with altered isotopic abundance. The "color" of the element shows its isotopic distribution, which can be measured using a mass spectrometer. In the first image the proportion between blue and green chips is 1:3 whereas it lies at 1:1 in the second image. This ratio, which defines the tag, is independent of the amount of black chips.
Credit: J.I. García Alonso et al.
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