Department of Radiochemistry, Institute of Atomic Energy, Beijing, China.
Department of Nuclear Physics, Institute of Atomic Energy, Beijing, China.
J Mass Spectrom. 2023 Feb;58(2):e4905. doi: 10.1002/jms.4905.
The determination of isotope ratios in individual uranium particles is very important for nuclear safeguards. In this work, accelerator mass spectrometry (AMS), thermal ionization mass spectrometry (TIMS), and secondary ion mass spectrometry (SIMS) were applied to isotope ratio analysis of individual uranium particles and compared in terms of background, measurement accuracy, and efficiency. Several individual uranium particles (1-7 μm) from certified reference materials were used as samples. The results show that the average values of blank counting rate of U for AMS, FT-TIMS (FT: fission track), SEM-TIMS (SEM: scanning electron microscope), and SIMS were 7.3, 7.8, 2.7 and 2.2 cps, respectively. The relative error of U/ U and U/ U isotope ratios of the particles from U200 for AMS were within 10% and 20%, whereas the results of FT-TIMS and SIMS were within 5% and 10%, respectively. The relative error and external precision of U/ U and U/ U of the particles from U850 for the method of AMS, SEM-TIMS, and SIMS were within 10% and 5%, respectively. For U/ U, the average values of the relative error and external precision measured by AMS were within 5%, which measured by SEM-TIMS and SIMS were all within 10%. AMS has advantages in measuring U/ U. The measurement time of AMS and SEM-TIMS was shorter than that of FT-TIMS and longer than that of SIMS. It is considered that AMS and SEM-TIMS have a certain development prospect, and it is necessary to research deeply.
单个铀颗粒同位素比值的测定对核保障非常重要。本工作采用加速器质谱法（AMS）、热电离质谱法（TIMS）和二次离子质谱法（SIMS）对单个铀颗粒的同位素比值进行了分析，并从本底、测量精度和效率等方面进行了比较。使用了几个来自认证参考材料的单个铀颗粒（1-7 μm）作为样品。结果表明，AMS、FT-TIMS（FT：裂变径迹）、SEM-TIMS（SEM：扫描电子显微镜）和 SIMS 中 U 的空白计数率平均值分别为 7.3、7.8、2.7 和 2.2 cps。AMS 测定的 U200 颗粒中 U/ U 和 U/ U 同位素比值的相对误差在 10%和 20%以内，而 FT-TIMS 和 SIMS 的结果在 5%和 10%以内。AMS、SEM-TIMS 和 SIMS 测定的 U850 颗粒中 U/ U 和 U/ U 的相对误差和外部精度均在 10%和 5%以内。对于 U/ U，AMS 测量的相对误差和外部精度的平均值在 5%以内，SEM-TIMS 和 SIMS 测量的相对误差和外部精度均在 10%以内。AMS 在测量 U/ U 方面具有优势。AMS 和 SEM-TIMS 的测量时间均短于 FT-TIMS，长于 SIMS。认为 AMS 和 SEM-TIMS 具有一定的发展前景，有必要进行深入研究。
