CALIBomb
Several ways of reporting 14C activity levels relative to a standard
are in use, but no convention has been established for reporting nuclear weapons
testing (post-bomb) 14C levels in samples. We advocate the use of
fraction modern with a new symbol F14C to prevent confusion
with the previously used Fm, which may or may not have been fractionation
corrected (Reimer, Brown and Reimer, 2004. "Discussion: Reporting and
Calibration of Post-Bomb14C Data", Radiocarbon 46, p 1299-1304)