Mass attenuation coefficients (MACs) of Th, U, Np, and Pu for oxygen X-rays have been experimentally determined using an electron microprobe. The MACs were obtained by measuring relative X-ray intensities emitted from ThO2, UO2, NpO2, and PuO2 targets, for incident electron energies from 5 to 30 keV, and processing them with the help of the computer program XMAC. The accuracy of the measured MACs is estimated to be better than 5%. Results are compared with MAC tabulations commonly used in electron probe microanalysis as well as with theoretical photoionization calculations. It is concluded that the MACs implemented in the Monte Carlo simulation program PENELOPE which are based on the photoionization cross-section calculations of Sabbatucci & Salvat [(2016). Theory and calculation of the atomic photoeffect. Rad Phys Chem121, 122–140], provide the best agreement with our measurements. The use of different MAC schemes for the analysis of mixed actinide oxide materials is discussed.

中文翻译：

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使用电子微探针测定氧 Kα X 射线的 Th、U、Np 和 Pu 的质量衰减系数

氧 X 射线的 Th、U、Np 和 Pu 的质量衰减系数 (MAC) 已使用电子微探针通过实验确定。MAC 是通过测量 Th2O 发射的相对 X 射线强度获得的2,2, NpO2, 和 PuO2目标，用于从 5 到 30 keV 的入射电子能量，并在计算机程序 XMAC 的帮助下对其进行处理。测得的 MAC 的准确度估计优于 5%。将结果与电子探针微量分析中常用的 MAC 表格以及理论光电离计算进行比较。得出的结论是，在 Monte Carlo 模拟程序 PENELOPE 中实施的 MAC 基于 Sabbatucci 和 Salvat [(2016) 的光电离横截面计算。原子光效应的理论与计算。辐射物理化学121, 122–140]，与我们的测量值提供了最佳一致性。讨论了使用不同的 MAC 方案分析混合锕系氧化物材料。