During the last 25 years, professional archaeologists have become accustomed to relying on a wide variety of experts, both on the dig and afterward. Today no excavation would go into the field without an architect and photographer, or hesitate to call in a numismatist or bone specialist to study the collected material. A geologist, a paleobotanist and an anthropologist are other frequent members of an expedition staff. Scientific techniques like carbon 14 and thermoluminescence are often used for dating. And now the nuclear physicist is helping solve the problem of where pottery was manufactured.
The provenance of pottery has always been of concern to archaeologists, for provenance may help to answer important questions of cultural influence, patterns of trade and, maybe, even trace migrations.
Elaborate pottery classifications based on form and decoration enable the archaeologist to determine chronological, cultural and even regional differences. (For example, the Iron Age pottery of the Northern Kingdom of Israel shows distinct differences from the pottery of the contemporaneous Southern Kingdom of Judah.) However, deciding what is an import and what is a good imitation is still a hard knot to untie.
Neutron activation analysis is the most recent technique for untying it.
Understanding this new technique requires an understanding of the nature of pottery. Pottery is made of clay to which other material, such as crushed rock or powdered straw, has been added to decrease shrinkage and increase strength (temper). The shaped object is then heated until certain chemical changes occur. (These chemical changes prevent the vessel from turning into mud every time it is washed.)