Plutonium measurements by accelerator mass spectrometry at LLNL

Abstract

Mass spectrometric methods provide sensitive, routine, and cost-effective analyses of longlived radionuclides. Here we report on the status of work at Lawrence Livermore National Laboratory (LLNL) to develop a capability for actinide measurements by accelerator mass spectrometry (AMS) to take advantage of the high potential of AMS for rejection of interferences. This work demonstrates that the LLNL AMS spectrometer is well-suited for providing high sensitivity, robust, high throughput measurements of plutonium concentrations and isotope ratios. Present backgrounds are ~2×10 7 atoms per sample for environmental samples prepared using standard alpha spectrometry protocols. Recent measurements of 239+240 Pu and 241 Pu activities and 240 Pu/ 239 Pu isotope ratios in IAEA reference materials agree well with IAEA reference values and with alpha spectrometry and recently published ICP-MS results. Ongoing upgrades of the AMS spectrometer are expected to reduce backgrounds below 1×10 6 atoms per sample while allowing simplifications of the sample preparation chemistry. These simplifications will lead to lower per-sample costs, higher throughput, faster turn around and, ultimately, to larger and more robust data sets.

Ultra-trace determination of plutonium in marine samples using multi-collector inductively coupled plasma mass spectrometry

“…Although the 240 Pu/ 239 Pu atom ratios are not certified, the ratios obtained for the reference samples (Table 4) agree with other reported values using various analytical techniques such as ICP-MS, accelerator mass spectrometry, thermal ionisation mass spectrometry and high-resolution ␣-spectrometry [6,19,[27][28][29]32,[35][36][37][38][39][40][41][42][43][44][45][46]. The precisions (n = 10) of the measurements ranged from 1.7% to 8.6% depending on the total Pu concentrations in the samples.…”

Isotope ratio analysis of actinides, fission products, and geolocators by high-efficiency multi-collector thermal ionization mass spectrometry

“…Thermal ionization mass spectrometry (TIMS) [72,[108][109][110][111][112], inductively coupled plasma mass spectrometry [113][114][115][116][117][118][119][120], secondary ion mass spectrometry (predominately for particle or surface analysis) [71,54], accelerator mass spectrometry (predominately for high abundance sensitivity analysis) [10,[121][122][123][124], and resonance ionization mass spectrometry (high elemental selectivity) [19,[125][126][127][128] are frequently utilized for analysis of actinides and other radionuclides. Glow discharge mass spectrometry has been used for isotope ratio analysis of actinides, such as uranium [129][130][131], as well as fission-track TIMS for particles [132].…”

Studies of Plutonium Aerosol Resuspension at the Time of the Maralinga Cleanup

“…After gamma spectroscopy, the UHV filters were analyzed by radiochemistry. At the conclusion of the rehabilitation at Maralinga, the UHV units were used to measure extremely low Pu concentrations in air, which demanded the use of accelerator mass spectroscopy methods (McAninch et al, 1999) to detect Pu on these special filters.…”