航放数据处理中出现负值的原因及解决方法

笔者通过对内蒙古阿拉善左旗测区的航放数据处理,总结了出现负值的过程及原因,主要有以下几点:(1)放射性蜕变具有统计涨落的性质,这一性质对数据修正中产生负值起着重要作用,尤其是在放射性核素含量偏低地区;(2)铀计数率经过本底和宇宙射线修正后会出现少量的负值,经过大气氡修正后负值数量进一步增加,并在测线两端容易出现高值假异常及连续的负值异常,经过康普顿散射剥离修正后,负值数量大量增加,而高度修正及含量换算则不再产生新的负值,仅改变负值大小。笔者在研究中发现,通过对修正过程产生的负值进行置零处理,能消除由大气氡修正而产生的高值假异常,但却出现连续的零值数据,不符合客观规律,因此提出用归一化法来消除负值,该方法可快速、合理地将负值消除,并能将改动后的值控制在一个较小值的范围内,弥补了目前对负值处理方法的缺失与不足。

Analysis and solution of negative values in airborne radioactivity data processing

In this paper,the authors processed the navigation data obtained from Alxa Left Banner in Inner Mongolia to summarize the process and main reasons for the formation of the negative value. The results are as follows:(1)The nature of radioactive decay has statistical fluctuation,and this property plays an important role in the processing of revised data,especially in areas with low radionuclide;(2)A slight negative value of uranium counting rate will occur after background correction and cosmic ray correction,and will increase negatively after atmospheric radon correction;both ends are prone to form high value false anomalies and continuous negative anomalies. After the peel correction,the number of negative values increases greatly,while the height correction and content conversion no longer produce new negative values,but only change the negative values. The authors found that zeroing the negative values generated by the correction process can eliminate high value false anomalies produced by atmospheric radon correction,and that continuous zero value data appear,which is inconsistent with the objective laws. Therefore,normalization method is proposed to eliminate negative values. This method can eliminate the negative value quickly and reasonably,and can control the changed value within a smaller value.In addition,it makes up for the lack and the deficiency of the negative value processing method.