Instrumentation and Software for Low-Level Liquid Scintillation Counting Radiocarbon Dating

In China, the development of 14C dating is closely related to that of liquid scintillation counting (LSC). New demands are continuously made on LSC by 14C dating, and at the same time, the development of LSC promotes 14C dating. Benzene synthesis for 14C sample preparation was first developed in China in 1974 by the 14C Laboratory of the Department of History, Peking University. This has laid the foundation for 14C dating by β counting with LS counters. Initially, we used a modified conventional LS counter. Despite its poor detection efficiency and high background, it did make a great contribution to 14C dating and LSC in China. Additional 14C laboratories were established for the fields of archaeology, geology, geography, vertebrate paleontology, marine geology and seismology, for which 14C dating is becoming an important research tool. At present, over 50 14C laboratories have been established in China; 90% of the labs use LS counters for β counting, most of which are manufactured in China. 14C dating in China has been primarily concerned with sample synthesis techniques. Since 1979, we have developed three types of LS counters. One is of conventional design; the others are with anticoincidence shielding. We describe here an anticoincidence-shielded LS counter.