一、问题的提出近几年低水平放射性测量技术得到了迅速地发展。在低水平放射性测量中,为了对一定的测量对象选择合宜的探测器和探测程序,就需要估计辐射探测器可能做出有意义的判断的最低放射性水平。因为放射性衰变是个随机过程,所以即使在完全相同的物理条件下对同一对象进行重复测量所得到的结果也不会完全相同,总会有一定的统计涨落。这样,我们面临的问题是:依据有限次测量结果(随机事件的个体)对所测对象(随机事件的总体)做出判断。例如,依据探测器的计数率判断所测对象是否有放射性。由于计数固有的统计性质,这种判断总有一定的发生错误判断的几率。可能发生的错误判断有两种: First, the issue put forward In recent years, low-level radiometric techniques have been rapidly developed. In low-level radiometric measurements, in order to select the appropriate detector and detection procedures for a given subject, it is necessary to estimate the lowest level of radiation that the radiation detector can make a meaningful judgment. Because radioactive decay is a random process, repeated measurements of the same object under the same physical conditions will not produce exactly the same results and there will always be some statistical fluctuations. In this way, we are faced with the problem of making a judgment on the measured object (the total of random events) based on a limited number of measurements (individuals of random events). For example, based on the count rate of the detector to determine whether the measured object is radioactive. Due to the inherent statistical nature of counting, there is always a chance that such judgments will misjudge. There are two possible wrong judgments: