基于Fe(OH)3-CaCO3载带的水中228Ra的γ能谱分析方法

建立了一种基于Fe(OH)₃-CaCO₃载带的水中²²⁸Ra的γ能谱分析方法，适用于环境水中²²⁸Ra的分析。采用Fe(OH)₃-CaCO₃共沉淀法富集水中的²²⁸Ra，将富集后的²²⁸Ra采用Ba(Ra)SO₄共沉淀法进一步载带，¹³³Ba示踪法确定²²⁸Ra的全程回收率，使用高纯锗γ谱仪测量与²²⁸Ra达到放射性平衡的衰变子体²²⁸Ac的特征γ能量，从而获得²²⁸Ra的分析结果。通过对5 L水样的加标验证可知，²²⁸Ra回收率为81.8%~87.5%，加标水样测量结果与添加量的相对偏差为1.7%~5.3%，此方法的探测限为57.2 mBq/L。

γ Spectrometry Analysis Method for 228Ra in Water Based on Fe(OH)3-CaCO3 Carrier

The γ spectrometry analysis method for ²²⁸Ra in water based on Fe(OH)₃-CaCO₃ carrier was developed, which is suitable for the analysis of 228Ra in environmental water. The enrichment method of ²²⁸Ra in water was carried out by Fe(OH)₃-CaCO₃ co-precipitation method. The enriched 228Ra was further loaded by Ba(Ra)SO₄ co-precipitation method, and ²²⁸Ra was determined by ¹³³Ba tracer method. The full recovery rate was measured using high-purity Ge γ spectrometer to measure the characteristic γ energy of the decaying daughter ²²⁸Ac, which reached the radioactive equilibrium with ²²⁸Ra, thereby obtaining the analysis result of 228Ra. Through the calibration of 5 L water sample, it is known that the recovery rate of 228Ra is in the range of 81.8%-87.5%. The relative deviation of the water sample measurement is 1.7%-5.3%, and the detection limit of this method is 57.2 mBq/L.