摘要目的 建立应用屏栅电离室谱仪同时分析样品中多种α核素的方法.方法 超声分散和真空干燥系统制备大面积样品源,应用大面积标准薄源和钚标准面源对屏栅谱仪测量条件进行优化,建立能量和效率刻度曲线,采用铀钍天然系矿石标准物质(GBW04127)对方法的准确性进行验证.结果 Np、Pu和Am大面积标准薄源的能量曲线非线性＜0.2％,线性良好.237Np、239Pu、241 Am的半峰宽分别为112、84和106 keV.大面积标准薄源的探测效率均值为31.2％.分析铀钍天然系矿石标准物质比活度测量值与标准值相一致.用该方法测得某铀矿石中232Th、238U、230Th、234U/226Ra、210Po、222Rn和218Po,比活度分别为5.3、3.8、35.6、21.4、27.0、19.6和11.1 Bq/g.结论 该方法能够快速分析环境样品中的多种α核素,适合低水平放射性环境样品的α谱分析.

abstractsObjective To develop the method of analyzing α-radionuclides using large area grid ionization chamber.Methods Ultrasonic dispersion and vacuum drying system was used to prepare sample source,large standard thin source and plutonium plane source were used to optimize the working condition of spectrometer,and calibrate the instrument for analyzing α emitters.The certified reference materials (GBW04127) were used to verify the accuracy of the method.Results The non-linearity of calibration curve for standard thin sources of neptunium,plutonium and americium was less than 0.2％,and the resolution were 112,84 and 106 keV,respectively.The counting efficiency was 31.2％ for the large standard thin source.The values of specific activity measured in this way were in good agreement with those of the certified reference materials.232Th,238U,230Th,234U/226Ra,210Po,222Rn and 218Po were analyzed in a uranium mineral sample,and their specific radioactivity values were 5.3,3.8,35.6,21.4,27.0,19.6 and 11.1 Bq/g,respectively.Conclusions The method can be used to analyze α spectrum quickly in low-level radioactive environmental samples.