多年来,已用α径迹法测定岩石和矿物中铀含量及空间分布,但这种方法的主要缺点是:即使铀含量在几百至几千 ppm,也需用较长的照射时间,而且所得α径迹中很难区分哪些是属于钍系衰变系列的,因此,如果不知道样品的 Th/U 比值,就较难独立 For many years, the uranium content and the spatial distribution of rock and mineral have been determined by the alpha-track method. However, the main disadvantage of this method is that a longer irradiation time is required even at uranium levels of a few hundred to a few thousand ppm, It is difficult to distinguish which ones belong to the series of thorium decay in the resulting α track and therefore it is more difficult to stand alone without knowing the Th / U ratio of the sample