What are the procedures for preparation, irradiation, and analysis of pottery, clays, temper, basalt, and other rock powders at MURR?
If sherd samples are large, we will remove two separate pieces about 1–2 cm² in area. One piece is used for NAA preparation and the second piece is retained in our archives for future reference. The inner and outer surfaces of the sherd are scraped using a drill burr made of either silicon carbide or tungsten carbide. The scraped specimens are subsequently brushed clean, washed in deionized water and dried for several hours. After drying, an agate mortar and pestle will be employed to crush and homogenize the pottery sample into a fine powder (about 500 mg). Clay samples are fired at 700° C before they are ground into a fine powder using procedures described in Cogswell et al. (1996). Basalt and other hard rock types should be ground into a powder before shipment to MURR, because the Archaeometry Lab does not have routine access to the equipment necessary to pulverize very hard rock specimens. All sample powders are then dried in an oven at 100° C for 24 hours and stored in a desiccato
