液闪分析中反符合屏蔽对各种放射性核素计数率的影响

摘要

采用有/无反符合屏蔽的3台液闪仪测定了多种放射性核素的计数率,结果表明:对α核素、纯β核素和不存在β-γ级联辐射的β/γ核素,反符合屏蔽对其计数率的影响可以忽略；但对存在pγ级联辐射的β/γ核素,反符合屏蔽使其β计数率显著降低.因此,用有反符合屏蔽的液闪仪进行绝对测量时必须考查待测核素的衰变特性.%Three liquid scintillation counters with/without anticoincidence shield have been used to determine the count rates for various kinds of radionuclides. The influences of anticoincidence shield on the count rates can be neglected for α-emitters, β-emitters and β/Υ emitters with no β-Υ cascade radiation. However, remarkable decreases of count rates are observed when anticoincidence shield is applied for β/Y emitters with β-Y cascade radiations. If liquid scintillation counter with anticoincidence shield is employed as absolute measurement method, the decay properties of the measured radionuclide should be in consideration.