北京大学AMS 14 C 国际比对样品测量*

介绍了北京大学加速器质谱(AMS)实验室参加国际原子能机构 (IAEA) 组织的第五届¹⁴ C国际比对样品测量的过程和结果,包括样品制备、小型¹⁴ C测量加速器质谱计装置和比对测量结果的统计分析等。北京大学的测量结果与IAEA加权统计平均值的偏差在1σ之内, 这一结果较客观地体现了我国¹⁴ C AMS年代测定在国际同类实验室中所处的地位。

THE AMS MEASUREMENT OF VIRI SAMPLES AT PEKING UNIVERSITY

The first phase of the Fifth International Radiocarbon Inter-comparison (VIRI) campaign has been organized by International Atomic Energy Agent (IAEA) from September 2004 to May 2005. The purposes of International Radiocarbon Inter-comparison are developing the ¹⁴ C dating technology and set a series of standard samples. It basically involves all the radiocarbon laboratories worldwide, both AMS and Conventional beta-counting ones. Peking University AMS laboratory took part in this campaign and have measured 4 samples of VIRI A, VIRI B, VIRI C and VIRI D. The sample preparation has been carried out in the school of archaeology and museology following a standard procedure. A CN analyzer was used for CO₂ preparation and CO₂ was reduced to graphite by H₂ and using Fe powder as catalyzer. Samples have been measured with a new compact AMS system at the institute of heavy ion physics. For checking the reliability of the measurement, three kinds of standards samples OXI, OXII and ANU sugar was used. The measurement results of these four samples are 108.78±0.38pMC, 110.48±0.39pMC, 2834±35aB.P. and 2859±28aB.P. respectively. They are in good agreement with the weighted average values of 109.10pMC, 110.70pMC, 2820aB.P. and 2836aB.P. , which are statistically calculated by IAEA based on the data from many laboratories in the world. The deviation is within 1σ.