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~(14)C年代测定方法在地质、考古等学科中得到广泛的应用。被测样品的年代了是通过测量样品中残存的~(14)C放射性比度A与大气~(14)C比度A_0之比,利用公式T=82671n(A_0/A)(年)计算而得。为建立我国“现代碳”标准样,我们于1980年用液体闪烁法对一系列~(14)C标准样作了标定。我们使用FJ-353型液体闪烁计数器和自制的放大分析器,采用了甄别单路小脉冲的串光甄别线路,对探头附加了铅屏蔽。仪器对~(14)C的探测效率η=73％,本底月=5.7cpm,优值η~2/B近1000。表1中列出某一标准样五次重复制样测量的结果。样品燃
~ (14) C dating method in geology, archeology and other disciplines are widely used. The age of the sample to be measured is determined by measuring the ratio of the radioactive isotope A of ~ (14) C remaining in the sample to the A_0 of the atmospheric ~ (14) C ratio using the formula T = 82671n (A_0 / A) Got it. In order to establish the “modern carbon” standard in our country, we calibrated a series of ~ (14) C standards by liquid scintillation in 1980. We used a FJ-353 liquid scintillation counter and a homemade magnification analyzer, using a crossover light screening circuit that scans a single, small pulse and attached a lead shield to the probe. Instrument detection efficiency of ~ (14) C η = 73%, the base month = 5.7cpm, excellent value η ~ 2 / B nearly 1000. Table 1 lists the results of a sample of five replicates of a standard sample. Sample burning