Choosing the best method for radiocarbon dating depends on the quantity of available sample or, in the case of expensive materials, how much of it you can afford to be destroyed. AMS dating, for example, involves burning a sample to convert it to graphite.
Advantages of AMS Radiocarbon Dating over Radiometric Analysis by LSC:
(a) small sample size needed (as little as 20 mg) thus it is recommended for radiocarbon dating of blood particles, grains, seeds, small artifacts, or very expensive or rare materials;
(b) takes less time than radiometric method (less than 24 hours);
(c) higher precision than radiometric techniques.
AMS dating is an advanced method compared to radiometric dating using liquid scintillation counters (LSC). Fees for AMS analyses are higher.
Beta Analytic no longer provides radiometric dating using LSC.
Samples submitted for radiometric dating will be reported as RadiometricPLUS, which combines large sample handling techniques with particle detection. Beta Analytic only provides RadiometricPLUS for charcoal, dung, peat, plants and seeds, shells, corals, and wood.
RadiometricPLUS – Standard service is for samples containing at least 3.0 grams to 4.0 grams of final carbon (remaining carbon after all necessary pretreatments and chemical syntheses have been performed). This service is less expensive than AMS dating. Results are reported in 30 business days.
AMS Dating – The AMS radiocarbon dating technique is suited for samples containing 0.00025 grams to 0.3 grams of final carbon. Quoted precision generally ranges from 0.5% to 3% of the sample age and is independent of sample size. Precision for AMS carbon dating results will be better than radiometric dating (LSC) analysis for samples that are more than 10,000 years old. Precision of results with Beta Analytic’s AMS dating and RadiometricPLUS service is the same.
NOTE: Sample size required by the lab is a conservative estimate. Normal pretreatment procedures can remove 30% to 70% of the original material sent. Water, adhering mineral matter, and carbon loss from essential chemical pretreatment are basic factors to consider when determining the amount of material required. For example, only 25% of the weight of a submitted, clean charcoal sample is available for analysis (1 gram final carbon from 4 grams submitted charcoal).