The prefix identifies the laboratory that processed the sample.The 'Wk' prefix shown here indicates that these samples were processed at the University of Waikato Radiocarbon Dating Laboratory.Because of the somewhat short half-life of 14C, radiocarbon dating is not applicable to samples with ages greater than about 50,000 years, because the remaining concentration would be too small for accurate measurement.Thermoluminescence dating: this method is associated with the effect of the high energy radiation emitted as a result of the decay or radioactive impurities.Archaeologists use the remains of the past to help solve the puzzles of history.
New Zealand The laboratory number is a unique identifier given to each radiocarbon sample.
Site numbers in the United States are based on the "Smithsonian Trinomial System" where each State has its own number (e.g., WA=45), the County within the state has a two letter abbreviation (e.g., Crook County = CR), and sites within the county are given numbers consecutively as they are found and recorded (i.e., 45xxnnn).
So, a site labelled as "45CR121" would be the 121st site recorded in Crook County, Washington.
This can be done very accurately, although some samples may be difficult to work with.
Beyond this, the accuracy of the date depends on the reliability of the assumptions used in interpreting the measurements (see below).