x = calibrated date (cat AD)
y = Radiocarbon determination (F14C)
FORENSIC
From 1950 to 1963 atmospheric testing of thermonuclear devices produced elevated levels of artificial carbon-14 in the atmosphere. Since 1963 the levels of 'bomb carbon' have declined as this artificial radiocarbon enters the biosphere. Today we are now almost back to the levels of radiocarbon in the early 1950s. As it is possible to derive radiocarbon ages for material that was once alive in this period, radiocarbon can be useful in providing ages for forensic specimens.
For the post-1950 period calibrated results can be provided to within two years if the material dated is not subject to the problems of bone collagen turnover effects or other related problems.
A wide range of organic materials can be dated in human forensic cases such as:
- human bone, skin and hair
- clothing with an organic origin, eg cotton and wool.
Dating by Accelerator Mass Spectrometry using only a small quantity of material (skin 20-40 mg, bone 200mg) cause a minimal amount of damage to forensic material.