Carbon dating notes
To get a mass large enough to handle, you needed to embed your sample in another substance, a "carrier." At first acetylene was used, but some workers ruefully noted that the gas was "never entirely free from explosion, as we know from experience."(4) Ways were found to use carbon dioxide instead.
Frustrating uncertainties prevailed until workers understood that their results had to be adjusted for the room's temperature and even the barometric pressure.
By 1950, Willard Libby and his group at the University of Chicago had worked out ways to measure this proportion precisely.
Their exquisitely sensitive instrumentation was originally developed for studies in entirely different fields including nuclear physics, biomedicine, and detecting fallout from bomb tests.(1) Much of the initial interest in carbon-14 came from archeology, for the isotope could assign dates to Egyptian mummies and the like.
For example, Hans Suess relied on a variety of helpers to collect fragments of century-old trees from various corners of North America.
But what looks like unwelcome noise to one specialist may contain information for another.
This was all the usual sort of laboratory problem-solving, a matter of sorting out difficulties by studying one or another detail systematically for months.
More unusual was the need to collaborate with all sorts of people around the world, to gather organic materials for dating.
Also, the Sun’s own magnetic field varies with the cycle, and that could change the way cosmic particles bombarded the Earth.
In 1961, Minze Stuiver suggested that longer-term solar variations might account for the inconsistent carbon-14 dates. Libby, for one, cast doubt on the idea, so subversive of the many dates his team had supposedly established with high accuracy.(9) Suess and Stuiver finally pinned down the answer in 1965 by analyzing hundreds of wood samples dated from tree rings.
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After a creature's death the isotope would slowly decay away over millennia at a fixed rate.