This is affected by solar activity and the earth’s magnetic field.
Luckily, we can measure these fluctuations in samples that are dated by other methods.
Tree rings can be counted and their radiocarbon content measured.
From these records a “calibration curve” can be built (see figure 2, below).
As not all objects absorb fluorine at the same rate, this also undermines the accuracy of such a dating technique.
Professor Willard Libby produced the first radiocarbon dates in 1949 and was later awarded the Nobel Prize for his efforts.
Both elemental fluorine and the fluoride ion are highly toxic.
The recommended maximum allowable concentration for a daily 8-hour time-weighted exposure is 0.1 ppm.
A huge amount of work is currently underway to extend and improve the calibration curve.
In 2008 we could only calibrate radiocarbon dates until 26,000 years.
This means that although they are very similar chemically, they have different masses.