Improved isotopic SIMS measurements of uranium particles for nuclear safeguard purposes

RIMS analysis of ion induced fragmentation of molecules sputtered from an enriched U3O8 matrix

“…While large geometry SIMS instruments have been used to analyze uranium oxide reference materials with high precision, SIMS can be hindered by mass coincidences from same-mass isotopes, hydrides and other molecular compounds [9]. RIMS achieves its selectivity spectroscopically and, therefore, is capable of overcoming these isobaric limitations.…”

“…A major focus for these types of measurements is on improving the sensitivity for the detection of uranium and transuranic isotopes in the presence of isobaric interferences without the need for complex and time-consuming sample preparation methods. Recently, secondary ion mass spectrometry (SIMS) has shown promise as an effective tool for the analysis of nuclear materials with high sensitivity and minimal sample preparation [8][9][10][11]. The sensitivity of SIMS is often defined by useful yield: the number of ions detected over the number of atoms removed during the analysis.…”

“…The sensitivity of SIMS is often defined by useful yield: the number of ions detected over the number of atoms removed during the analysis. SIMS analysis of U 3 O 8 standards has achieved useful yields of 1-2% using high mass resolution, multi-collector instruments [9].…”

Latest improvements in isotopic uranium particle analysis by large geometry–secondary ion mass spectrometry for nuclear safeguards purposes

“…Good detection limits for 236 U can be reached by SIMS on low enriched material but to a lesser extent on high 235 U enriched or weapon grade materials due to the higher hydride ( 235 U 1 H) contribution that interferes with the 236 U isotope. 6,10 In this paper, we present some of the latest developments that were implemented in order to increase the precision in the uranium isotopic measurements as well as to improve the detection limits of 236 U. This includes the optimization of the analytical protocol and new capabilities now available in the CAMECA acquisition and data processing software.…”

“…Recently, the performance of SIMS measurements for this application has been greatly improved using large geometry-SIMS (LG-SIMS) instruments that provide both automated screening capabilities to locate particles of interest as well as high precision isotopic measurements using a multi-ion counting detector system. [6][7][8][9] Low detection limits and low uncertainties are generally required for isotopic analysis of these micrometer to submicrometer particles. Samples taken from uranium enrichment facilities allow to investigate the production details and the used feed material by analyzing the 234 U/ 235 U and 236 U/ 235 U isotope ratios.…”