Accurate automatic analysis of individual uranium particles to improve the timeliness of safeguards environmental sample analysis using an LG-SIMS instrument and SEM-micromanipulation

Abstract

A new method for automated overnight analysis of individual uranium particles using a large-geometry secondary ion mass spectrometry (LG-SIMS) instrument was proposed and demonstrated to improve the timeliness of safeguards environmental sample (ES) analysis in this study. In SIMS analysis of ES, the particle-mixing effect, which indicates non-existent uranium isotopic abundances within a sample, reduces the accuracy of SIMS results and makes automatic SIMS analysis of individual uranium particles challenging. Therefore, we proposed and demonstrated a new automatic SIMS analysis combined with micromanipulation using test samples to compare the accuracy of the new automatic method and the conventional manual and automatic methods. Specifically, 22.5% and 57.5% of the results measured by the conventional manual and automatic methods were inaccurate due to the particle-mixing effect, respectively. In contrast, all results obtained with the new automatic method agreed with the respective reference values of uranium isotopic standard powders in test samples. The new automatic method successfully improved the accuracy of automatic individual particle analysis. The new automatic method also demonstrated the capability of improving the timeliness of ES analysis through overnight automated measurement of 40 individual uranium particles with high accuracy.