There have been different methods of measuring carbon-14 since Willard Libby pioneered the radiocarbon dating technique in the 1940s – from the radiometric techniques of gas proportional counting and liquid scintillation counting to the more recent accelerator mass spectrometry (AMS).
When the weakly radioactive carbon-14 decays, it undergoes beta (β) decay producing nitrogen-14 and a beta particle. Radiometric dating involves quantifying the amount of carbon-14 present by measuring the emitted beta particles from its radioactive decay. Gas proportional counting involves converting samples to CO2 gas followed by detection and counting of the beta particles.
Liquid scintillation counting involves converting the sample into a carbon-rich liquid, which is then added to a scintillator. When beta particles are emitted, the scintillator will emit a flash of light. When both of the detectors present pick up the flash, it is counted and used to calculate the amount of carbon-14 present.
AMS has become the standard in the industry for measuring carbon-14 content and offers several advantages over radiometric techniques. In contrast, it measures the carbon-14 directly, relative to the carbon-12 and carbon-13 present, rather than measuring the products of its radioactive decay.
The minimum sample requirements for AMS dating are significantly smaller than for radiometric dating techniques, allowing even a few milligrams of sample to be dated for certain sample types. Not only are the results more accurate and precise, the AMS analyses are also completed much faster.
Beta Analytic no longer offers radiometric dating by liquid scintillation counting. All samples submitted for radiocarbon dating are measured by AMS.
The ISO 17025-accredited lab’s standard AMS dating service reports results within 14 business days, with faster services also available. The Miami-based lab provides unlimited technical support throughout the process. Results and pending analyses are available online 24/7. For inquiries, please contact the lab.
This entry was posted on Friday, August 10th, 2018 and is filed under Beta Articles .