Improvements of PKUAMS for precision 14C analysis of the project of Xia-Shang-Zhou Chronology

To meet the requirements of the Xia-Shang-Zhou Chronology project, an upgrade of the AMS facility at Peking University has been carried out, commencing in 1996, and a new sample preparation system with high efficiency and low memory has been set up in the Department of Archaeology. A NEC MC-SNICS ion source has been installed and the injection system has been reconstructed. Computer control of the beam line has been implemented using Group 3 ControlNet, and a; new data acquisition system has been developed. The alignment and vacuum of the beam line have also been improved. The upgraded system was commissioned in 1998. Subsequent experience has led to efficient procedures for beam tuning and C-14/C-13 measurement. A precision of 0.5% in the C-14/C-13 ratio has been achieved. Many samples have now been measured for the Xia-Shang-Zhou Chronology project. (C) 2000 Elsevier Science B.V. All rights reserved.