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我院缓发中子测铀装置从1983年底投入使用至今的两年里,分析了一万多个含微量铀的样品,其中绝大多数是地质化探样品,特别是水系沉积物和土壤样品。这些样品的铀含量一般在零点几到几个ppm之间,用化学荧光比色法很难测得准确,而缓发中子计数法测微量铀的相对统计误差可小于5％。本方法在地质化探方面的效果是很显著的,图1和图2是荧光比色法和缓发中子计数法同时分析某地区地质化探样品后标出的铀含量的等值图。在图1中荧光比色法标出了8个铀含量高于3ppm的异常
In our two-year trial since the end of 1983, we have analyzed more than ten thousand samples containing trace amounts of uranium, the vast majority of which are geochemical exploration samples, especially sediments and soil samples . The uranium content of these samples is generally between a few tenths and a few ppm, it is very difficult to be measured accurately by chemical fluorescence colorimetry, and the relative statistical error of the measured uranium in the delayed neutron counting method can be less than 5%. The effect of this method on geochemical exploration is significant. Figures 1 and 2 are iso-values of uranium content after simultaneous geochemical profiling of a certain area by fluorescence colorimetry and delayed neutron counting. Fluorescence colorimetry in Figure 1 shows eight anomalies with levels of uranium above 3 ppm