Abstract: We use the Chinese Sucrose Standard and synthetical benzene as well as 13 paired-samples to assess the performance of a new Quantulua-1220 bought in July,2004. The results show that:1) when the background is below 0.5cpm and the fluctuation does not exceed 4‰ in the measuring surrounding,we infer the maximum datable age for this instrument would be up to almost 48ka; 2) The quench SQP(E) parameters of 261 radiocarbon samples vary from 700 to 758. The median is 735.522 and standard deviation is 9.150 57. The maximum age error caused by quenching factor is below 80a; 3) The t test results of 13 paired-samples indicate that the new Quantulua-1220 became stable after it ran for 10 months and the ages are indistinguishable in statistical test from ages supplied by other similar LSCs.

Key words: radiocarbon dating, quench calibration, liquid scintillation counter

摘要： Quantulua-1220型低本底高灵敏度液闪仪是¹⁴C测年系统中的关键设备,其质量直接影响¹⁴C测年数据的准确性,文中使用中国糖碳、合成本底和成对样品来评估新购置的Quantulua-1220型低本底液闪仪的本底、探测效率及仪器的长期稳定性等重要性能指标是否满足¹⁴C测年要求。测试结果表明,在一般工作环境下,液闪仪的本底低于0.5cpm,最大可测¹⁴C年龄估计值为48ka;由于猝灭因素引起的年龄偏差不超过100a,新液闪仪经过10个月的运行后,所测定的¹⁴C年龄具有可对比性。

关键词: ¹⁴C测年, 猝灭校正, 液闪仪