γ谱测量中非长期平衡的识别

目的确定含天然放射性物质的物料是否处于非长期平衡，以及衰变链中那些长寿命核素被分离或减少。方法γ能谱测量中，长期平衡时天然放射系中各子体的活度浓度与母体相同，在非长期平衡时，各子体及母体的活度浓度各不相同。结果处于长期平衡和非长期平衡的物料，在判断它们是否“放射性物质”时，所依据的核素种类及其豁免活度浓度是不一样的；它们的辐射剂量计算也是不一样的。结论γ能谱测量中对非长期平衡的识别非常重要。

Distinguish Natural Sources out of Secular Equilibrium with Their Parents or Daughters in Gamma Ray Spectrum Analyses

Objective To determine materials containing natural radionuclides in or out secular equilibrium with their parents or daughters. Methods In gamma ray spectrum analyses, the activity concentration of every daughter is the same as that of its parent when the material is in secular equilibrium. The activity concentrations of daughters and their parents are different when the material is out of secular equilibrium. Results It is different to determine whether the exposures from these materials should be exempt that materials containing natural radionuclides are in or out of secular equilibrium with their parents or daughters. Conclusion It is important to determine materials containing natural radionuclides in or out secular equilibrium with their parents or daughters in gamma ray spectrum analyses.