闪烁液及淬灭校正方法对液闪测量55Fe的影响

    Effect of Scintillation Cocktail and Quenching Calibration Method on Measurement of 55Fe by LSC

    • 摘要: 为了优化液体闪烁计数器(LSC)测量55Fe的条件,测试了三种商用闪烁液和两种淬灭校正方法对LSC测量55Fe的影响。配制与放化处理后基质相同的55Fe样品进行测量,三种闪烁液中,Ultima Gold AB样品装载量最大;在不同混溶比条件下,Ultima Gold LLT探测效率最高、最低检测限最小,混溶比为1∶4时,Ultima Gold LLT的探测效率最大为49.1%,同时最低检测限最小为0.12 Bq;若样品采用与淬灭标准源不同的闪烁液,对结果的准确度会造成一定的影响,在实验条件下活度测量值与标称值最大平均相对偏差绝对值为3.55%。对比tSIE法和TDCR法两种淬灭校正方法,TDCR法能够消除由于颜色和化学淬灭同时存在对55Fe液闪测量结果所造成的影响,是测量55Fe准确性更高的方法。通过加标样品验证,颜色及化学淬灭校正曲线得到的测量值与预期值的相对偏差分别为-0.35%~0.40%、-0.91%~-0.16%。

       

      Abstract: In order to optimize the measurement conditions of 55Fe by liquid scintillation counting, the effect of three kinds of commercial scintillation cocktail and two efficiency correction methods on LSC measurements of 55Fe was tested. Configuration of 55Fe samples with the same matrix as after radiochemical treatment for measurement, Ultima Gold AB has the highest sample loading among the three kinds of scintillation cocktail; the counting efficiency of Ultima Gold LLT is the highest and the MDA is the lowest under different miscibility ratios, and the maximum detection efficiency of Ultima Gold LLT is 49.1% when the miscibility ratio is 1∶4, while the MDA is 0.12 Bq. If the sample uses scintillation cocktail different from the quenched standard source, it will have an impact on the accuracy of the results, with an absolute value of maximum average relative deviation is 3.55% between the measured and expected values under experimental conditions. Comparing the two quenching calibration methods of tSIE and TDCR, the TDCR method can eliminate the influence caused by the simultaneous presence of color and chemical quenching on the 55Fe LSC measurement results, and is a more accurate method for measuring 55Fe. The relative deviations between the measured and expected values obtained from the color and chemical quenching calibration curves are -0.35% to 0.40% and -0.91% to -0.16%, respectively, as verified by the spiked samples.

       

    /

    返回文章
    返回