Compared to conventional radiocarbon techniques such as Libby's solid carbon counting, the gas counting method popular in the mid-1950s, or liquid scintillation (LS) counting, AMS permitted the dating of much smaller sized samples with even greater precision.Regardless of the particular 14C technique used, the value of this tool for archaeology has clearly been appreciated.Check Swipe Protocol (C measurements can be provided at additional cost. and Canada, we recommend shipping by airmail, priority mail, or courier. Customs should be clearly labeled on outside pack "SCIENTIFIC SAMPLES - NO COMMERCIAL VALUE".
If this is not the case, more sample material will be required.Please follow the guidelines described below: _____Never store material under conditions that might allow fungal or bacterial growth: If possible, try to keep samples frozen or dry._____Never handle samples in, or use implements and tools from, labs where tracer C might have been used. _____ Avoid wrapping samples in paper, or packing in containers that are lubricated with oil, waxes or any other organic materials.For example, rootlet intrusion, soil type (e.g., limestone carbonates), and handling of the specimens in the field or lab (e.g., accidental introduction of tobacco ash, hair, or fibers) can all potentially affect the age of a sample.Bioturbation by crabs, rodents, and other animals can also cause samples to move between strata leading to age reversals.The introduction of "old" or "artificial" carbon into the atmosphere (i.e., the "Suess Effect" and "Atom Bomb Effect", respectively) can influence the ages of dates making them appear older or younger than they actually are.