A preliminary study of small-mass radiocarbon sample measurement at   Xi'an-AMS
  To meet the measurement demands on small-mass radiocarbon (carbon content at 10-6g level) which are becoming increasingly significant. Xi'an-AMS has made improvement to the existing method of sample loading and has upgraded the Cs sputter ion source from the original SO-110 model. In order to study the feasibility of small-mass samples in Xi'an-AMS and evaluate the radiocarbon sample preparation ability using existing routine systems of H2/Fe and Zn/Fe, the small-mass samples prepared by four different methods are tested. They are mass division method, mass dilution method, H2/Fe reduction method and Zn/Fe reduction method. The results show that carbon mass above 25ug can be prepared using the existing Zn/Fe system, but no less than 100ug is required using the existing H2/Fe system, which can be improved. This indicates Xi'an-AMS are now able to analyze small-mass radiocarbon samples. 
Fu Yun-Chong, Zhou Wei-Jian, Du Hua, Cheng Peng, Zhao Xiao-Lei, Liu   Qi, Lu Xue-Feng, Zhao Wen-nian
physics.ins-det