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129I是一半衰期较长的放射性核素,是核电站中的裂变产物,对于监控核电站安全运行有重要意义。环境样品中的129I同位素为痕量。目前,加速器质谱技术(AMS)是实现129I高灵敏测量的最佳方法。由于环境样品中的I较少,须通过加入载体载带,而载体中的129I对实验结果有重要影响,所以确定加入的载体的量十分重要。由相对不确定度公式可得:m/M=(2β/9α)·(126.9/199)式中:m为样品中碘总量;M为KI载体量;α为样品中129I与127I的原子数比;β为载体中129I与127I的原子数比。若相对不确定度小于20%,则m/M须大于等于(2β/9α)·(126.9/199)。对载体加
129I is a half-life radionuclide that is a fission product in nuclear power plants and is of great significance for monitoring the safe operation of nuclear power plants. The 129I isotope in environmental samples is trace. At present, Accelerator Mass Spectrometry (AMS) is the best way to achieve a highly sensitive measurement of 129I. Since I in the environmental sample is less, by adding carrier carrier, and 129I in the carrier have a significant impact on the experimental results, it is important to determine the amount of carrier added. The relative uncertainty of the formula can be obtained: m / M = (2β / 9α) · (126.9 / 199) Where: m is the total amount of iodine in the sample; M is the KI carrier amount; α is the 129I and 127I atoms Number ratio; β is the atomic ratio of 129I to 127I in the support. If the relative uncertainty is less than 20%, m / M must be greater than or equal to (2β / 9α) · (126.9 / 199). Add on the carrier