热电离质谱直接测定铀氧化物中氧同位素

Direct Determination of Oxygen Isotope in Uranium Oxide by Thermal Ionization Mass Spectrometry

摘要: 本文研究了热电离质谱（TIMS)直接测量粉末状铀氧化物中氧同位素的方法，涉及主要测量条件包括环境中氧、样品带材料、样品颗粒大小和测量方式等对测量结果的影响。对仪器的相关测量参数进行了优化，并建立了TIMS直接测量粉末状铀氧化物中¹⁸O、¹⁶O原子个数比的方法。对TIMS法与经典测量氧同位素的氧化法的测量结果进行了比较，两者的相对偏差为0.2%。TIMS法的¹⁸O、¹⁶O原子个数比测量精度优于0.28%。

Abstract: The thermal ionization mass spectrometry (TIMS) method for direct determination of the oxygen isotopic ratio in uranium oxide powders was established through eliminating the influence of oxygen in the environment, sample particle sizes, material of rhenium and tantalum filaments and measurement mode on results. The measurement parameters of mass spectrometer were optimized. The experimental results show that the relative deviation of TIMS method result and oxidation method result is 0.2%. The measuring precision of TIMS is better than 0.28%.