NaI(Tl)晶体对点源γ射线的总效率,在不少文献上可以查到。但这些计算仅限于点源位于晶体的中心轴上,而点源位于非中心轴上的总效率却很难查到。此外,在已发表的数据中,仅适用于英制单位的晶体规格,而国产NaI(Tl)晶体按国际单位制度量其规格大小,因此直接引用这些发表过的数据会带来一定的误差。 The total efficiency of NaI (Tl) crystals on point source gamma rays can be found in a number of literatures. However, these calculations are limited to the fact that the point source is located on the central axis of the crystal, whereas the total efficiency of the point source on the non-central axis is hard to detect. In addition, the published data only apply to the crystal specifications of the English units, while the domestic NaI (Tl) crystals measure their specifications according to the International System of Units. Therefore, direct quotation of these published data will bring some errors.