Rehabilitation of the Laboratoire de Carbone 14-Dakar (Senegal) with a super low-level liquid scintillation counting system.

Abstract

Following the passing of Prof Cheikh Anta Diop in 1986, the radiocarbon laboratory (LC14) he created 20 yr earlier at the Institut Francophone d'Afrique Noire (IFAN), Dakar, Senegal, fell into a long hibernation. It took nearly 3 yr to renovate the laboratory and reinstall new equipment in order to return LC14 to full functionality and resume its activity. A new dating system has been implemented around a super low-level liquid scintillation spectrometer from Packard, the Tri-Carb 3170TR/LS, located in an underground room. In this paper, we assess the performance of the dating setup (background level and figure of merit) using known samples from Paris 6 and international standards from the International Atomic Energy Agency (IAEA). After the calibration, the setup was used to study bole seashells from the Khant area in the northern part of Senegal (West Africa). The aim is to present evidence of the correlation between the transgression of the Nouakchottan (5500 BP) and a few industries in the Khant area. The corresponding ages are difficult to assess and the dates available for this cultural site are randomly distributed, ranging from 4500 to 1500 BP, i.e., a chronological period spanning from the Neolithic to the Iron Age.