Building an Internal Conversion Electron Spectrometer with High Resolution for Analysis of Actinide Nuclides

大多数氡系核素都是α发射体，而且由于其较高的内转换系数，通常具有极低的光子强度。因此，α射线光谱分析已取代伽马射线光谱分析，被广泛地作为一种标准的分析工具来鉴定和测定鳗系核素。不幸的是，阿尔法射线能谱仪没有能力区分相差约10keV的能团。然后，很难分析诸如&lt；@D1239@&gt；D2Pu和&lt；@D1240@&gt；D1Pu等混合物。此外，物质中的高能量损失促使尾矿降低阿尔法射线谱中的能量，进而成为无限薄和失重来源的关键要求。研制了一种采用无窗口Si(Li)探测器的具有良好能量分辨率的内转换电子能谱仪。对于42keV的电子，能量分辨率为0.48keV。从能谱仪的检查中发现，电子和伽马射线的能量分辨率的差异主要是由于电子在探测器的吸收层中的能量分散所致。电子的相对效率曲线用探测器中的电子背向散射和电子从边缘逃逸来定量地解释。对~lt；@D1240@&gt；D1Pr to&lt；@D1239@&gt；d1同位素比值进行了ICE光谱分析，结果表明，该同位素比值测定具有良好的准确度和精密度。

Most of the actinide nuclides are alpha-emitters and furter the actinide nuclides often have extremely low photon intensities due to their high internal conversion coefficients. Therefore, alpha ray spectrometry has been widely used as a standard analytical tool for identification and assay of actinide nuclides, instead of gamma ray spectrometry. Alpha ray spectrometer, unfortunately, has no capability to separate an energy group differing by about 10 keV. Then, it is difficult to analyze the mixtures such as <@D1239@>D2Pu and <@D1240@>D1Pu. Moreover, the high energy losses in a matter invoke tailings to lower energy in the alpha ray spectrum and further a critical requirement for an infinitely thin and weightless source. An internal conversion electron spectrometer with excellent energy resolution using a windowless Si(Li) detector was developed. The energy resolution was 0.48 keV in FWHM for 42 keV electrons. From the examination of the spectrometer, the difference of energy resolution between for electrons and for gamma rays was found to be predominantly due to the energy straggling of electrons through the absorbing layer of the detector. And the relative efficiency curve for electrons were quantitatively explained in terms of electron backscattering in the detector and electron escape from the edge. The analysis of the <@D1240@>D1Pr to <@D1239@>D1 isotope ratio was made by ICE spectrometry and it was found that the isotope ratio can be determined with excellent accuracy and precision.