Faults with radio carbon dating

A more recent innovation is the direct counting of c14 atoms by accelerator mass spectrometers (AMS).The sample is converted to graphite and mounted in an ion source from which it is sputtered and accelerated through a magnetic field.

The first measurements of radiocarbon were made in screen-walled Geiger counters with the sample prepared for measurement in a solid form.This is the clock that permits levels of c14 in organic archaeological, geological, and paleontological samples to be converted into an estimate of time.The measurement of the rate of radioactive decay is known as its half-life, the time it takes for half of a sample to decay.The diminishing levels via decay means that the effective limit for using c14 to estimate time is about 50,000 years. Subsequent work has shown that the half-life of radiocarbon is actually 5730 ± 40 years, a difference of 3% compared to the Libby half-life.However, to avoid confusion all radiocarbon laboratories continue to use the half-life calculated by Libby, sometimes rounding it to 5570 years.