Raw, i.e., uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" (BP), "Present" being defined as 1950.
Despite this, however, caution is still necessary in accepting dates derived from carbon dating.
Libby estimated that the steady state radioactivity concentration of exchangeable carbon-14 would be about 14 disintegrations per minute (dpm) per gram.
In 1960, he was awarded the Nobel Prize in chemistry for this work.
The method was developed immediately following World War II by Willard F.
Libby and coworkers and has provided age determinations in archeology, geology, geophysics, and other branches of science.