Beta Analytic Laboratory’s Range and Detection Limits

Beta Analytic radiocarbon dating lab is ISO/IEC 17025:2005-accredited to perform chemical testing on the following:

* Archaeological / Geological Materials and Water

– Specific tests or properties measured: Determination of radiocarbon age / activity, Measurement of 14/13C, 14/12C, 13/12C

– Technique Used: Accelerator Mass Spectrometry (AMS)

– Range: From Present Day back to 47,000 years BP

– Detection Limits: 47,000 BP

* Organic and Carbonate Materials and Water

– Specific tests or properties measured: Determination of Stable Isotope Ratios, Measurement of δ13C, δD, δ15N and δ18O

– Technique Used: Stable Isotope Ratios by Isotope Ratio Mass Spectrometry (IRMS)

– Range: -100 per mil to 100 per mil

– Detection Limits: 0.05 mV mass 13 output

Background Detection Limit

AMS Dating Detection Limits

The practical background detection limit for radiocarbon dating by liquid scintillation counting (LSC) or AMS has long been argued and researched.

Some laboratories will analyze a sample one time and report a finite result, e.g. 48000 +/- 500 or 53000 +/- 2500. Beta Analytic’s own research has shown that such reports on a single analysis can be very misleading. In the past, Beta Analytic has sent graphite splits of the same exact graphite produced from Miocene-aged coal to as many as seven different AMS labs and obtained finite quotes of ages between 42000 to 53000.

These variances in detection limits have also been illuminated in the various International Radiocarbon Intercalibration Studies (TIRI, FIRI, VIRI), where sub-fossil or fossil samples yielded a range of results from finite to greater-than and not always in the right direction.

Beta Analytic has set a real and conservative limit of greater than 43500 BP when the activity of the material is statistically the same as the background. This is a credible number based on the lab’s own internal AMS limits. As such, Beta Analytic does not quote finite ages in excess of 43500 BP. Samples that yield an activity at or below this are reported as “greater than” 43500 BP.