The SUERC team measured the levels of a radio- isotope of carbon called
carbon-14 in each sample.
"But, because distilling reduces any impurities in the original grain, the only radioactivity the researchers could detect in the alcohol is natural
Carbon-14 at the same level you would expect in any spirit drink."
Instead of using a logarithmic scale for exponential decay of
carbon-14, the authors used a graph with the scale of percent modern carbon: it shows visually the decrease of
carbon-14 with the passage of time, due to radioactive decay (see fig.
A
Carbon-14 analysis of the samples proved the site dates back to 3100 BC.
In the ever-changing, technology-driven pharmaceutical industry,
carbon-14 labeling remains "hot" and is still the first-choice technology for labeling active pharmaceutical ingredients (APIs) and their metabolites.
The Bristol team has found a way to essentially scrape away the most radioactive parts of the graphite blocks--the parts containing
carbon-14, a radioactive isotope of carbon.
This method makes use of the so-called "bomb curve", which is a graph--shaped roughly like an inverted "V"--showing changes in
carbon-14 levels in the atmosphere.
The negative correlation still holds true, though energetic particles from solar "superflares" can trigger
carbon-14 creation; see page 22.
Carbon dating works by measuring the amount of
carbon-14 versus non-radioactive carbon (C) found in an object.
In the air, cosmic rays convert stable nitrogen-14 into radioactive
carbon-14. Organisms absorb radioactive carbon alongside stable carbon.
Discussing radioactivity, connection is made between
Carbon-14 dating and the Shroud of Turin.
However, carbon dating--a commonly used method of dating very old objects that compares the decay of a radioactive isotope to that of a stable isotope--utilizes
carbon-14. In ice dating, this is problematic, because
carbon-14 is produced by cosmic rays in the ice itself, and the technique only dates ice back about 50,000 years, limiting its accuracy.
