With support from the National Science Foundation, the University of Washington luminescence dating laboratory headed by Dr. James Feathers will purchase a Riso automated TL/OLS reader with automated processor which permits single grain luminescence determinations. Because of its increased efficiency over the instrument the laboratory currently employs, the Riso machine will both increase throughput and decrease cost per sample.
The Washington laboratory is the sole facility in the United States which routinely provides several types of luminescence analysis (TL, OSL, IRSL) for archaeological samples and the resultant dates have come to play an increasingly important function for archaeologists. Because organic materials are present in only a limited number of sites many such occurrences are not amenable to radiocarbon dating and often luminescence provides the only alternative. Using a range of approaches it often possible to obtain dates from either ceramics or soil and in the former case luminescence has an advantage over radiocarbon since it can directly date the object of interest rather than associated material. Dr. Feathers has shown that luminescence may be as accurate as radiocarbon. Traditional luminescence techniques analyze bulk samples comprised of many individual grains and the results can be problematic since particles of multiple ages and exposure histories may be present. Machines such as the Riso automated reader avoid this problem since they can date individual grains. A distribution of individual readings provides insight into the nature of the sample itself - both admixture and differential degree of bleaching - and therefore the multiple determinations allow accuracy to be better determined.
Dr. Feathers' research is directed at both improvement of the technique itself and its application to anthropologically significant archaeological sites. He has addressed questions such as the development of complex societies in the southern United States, the time of human entry into the New World and the emergence of modern human behavior in sub Saharan Africa. Acquisition of the Riso instrument will significantly increase the effectiveness of such research.
