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All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

U-Pu and Ba-Cs isotopic measurements on Trinitite by laser ablation sampling on the Neoma MC-ICP-MS

In this study we present the results of combined U-Pu and Ba-Cs isotope measurements obtained by laser ablation (LA) sampling of two glassy debris fragments (‘Trinitite’) from the world's first atomic bomb detonation conducted in New Mexico on July 16, 1945. Our primary goal in conducting these measurements was to understand whether examination of the U-Pu and Ba-Cs systematics by direct sampling (e.g. without any chemical separation or purification prior to isotope ratio measurement) could yield meaningful information that would differentiate the Trinitite fragments from glassy material lacking a nuclear fission signature. These measurements were conducted on a ThermoFisher Scientific Neoma multi collector – inductively coupled plasma – mass spectrometer (MC-ICP-MS), which is a relatively new MC-ICP-MS platform, so we also examine the behavior of these isotope systems in standards sampled in solution and via LA. Unsurprisingly, the measurements made on purified solutions of the U, Pu, and Ba isotopic standards produce high precision isotope ratios. Furthermore, this extends to the U-Pu measurements made by LA sampling, with the expected degradation in precision and accuracy related to matrix effects and signal intensity fluctuation. However, the Ba-Cs data acquired by LA is of low precision across all of the matrices examined and bears evidence of complex mass fractionation that will require further investigation to resolve. In total, our results indicate that the observed U-Pu isotope data are of sufficient quality to accurately constrain the U and Pu isotopic composition of glass containing sub-ppm levels of these elements which in turn could be used to differentiate glass containing anthropogenic fission products from natural glass whereas the Ba-Cs LA data cannot be used for this purpose until further methodological refinement is performed.

Ba-Cs↗
DOE OSTI2020

Materials Data on CsBa3 by Materials Project

CsBa3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cs is bonded to twelve Ba atoms to form CsBa12 cuboctahedra that share corners with four equivalent CsBa12 cuboctahedra, corners with eight equivalent BaCs4Ba8 cuboctahedra, edges with eight equivalent CsBa12 cuboctahedra, edges with sixteen equivalent BaCs4Ba8 cuboctahedra, faces with four equivalent CsBa12 cuboctahedra, and faces with fourteen BaCs4Ba8 cuboctahedra. There are four shorter (4.59 Å) and eight longer (4.70 Å) Cs–Ba bond lengths. There are two inequivalent Ba sites. In the first Ba site, Ba is bonded to four equivalent Cs and eight Ba atoms to form BaCs4Ba8 cuboctahedra that share corners with twelve equivalent BaCs4Ba8 cuboctahedra, edges with eight equivalent CsBa12 cuboctahedra, edges with sixteen BaCs4Ba8 cuboctahedra, faces with four equivalent CsBa12 cuboctahedra, and faces with fourteen BaCs4Ba8 cuboctahedra. There are four shorter (4.59 Å) and four longer (4.70 Å) Ba–Ba bond lengths. In the second Ba site, Ba is bonded to four equivalent Cs and eight equivalent Ba atoms to form BaCs4Ba8 cuboctahedra that share corners with four equivalent BaCs4Ba8 cuboctahedra, corners with eight equivalent CsBa12 cuboctahedra, edges with twenty-four BaCs4Ba8 cuboctahedra, faces with six equivalent CsBa12 cuboctahedra, and faces with twelve BaCs4Ba8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsBa3 by Materials Project

CsBa3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Cs is bonded to twelve equivalent Ba atoms to form CsBa12 cuboctahedra that share corners with twelve equivalent CsBa12 cuboctahedra, edges with twenty-four equivalent BaCs4Ba8 cuboctahedra, faces with six equivalent CsBa12 cuboctahedra, and faces with twelve equivalent BaCs4Ba8 cuboctahedra. All Cs–Ba bond lengths are 4.67 Å. Ba is bonded to four equivalent Cs and eight equivalent Ba atoms to form BaCs4Ba8 cuboctahedra that share corners with twelve equivalent BaCs4Ba8 cuboctahedra, edges with eight equivalent CsBa12 cuboctahedra, edges with sixteen equivalent BaCs4Ba8 cuboctahedra, faces with four equivalent CsBa12 cuboctahedra, and faces with fourteen equivalent BaCs4Ba8 cuboctahedra. All Ba–Ba bond lengths are 4.67 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsBa3 by Materials Project

CsBa3 is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Cs is bonded in a body-centered cubic geometry to fourteen Ba atoms. There are eight shorter (4.52 Å) and six longer (5.22 Å) Cs–Ba bond lengths. There are two inequivalent Ba sites. In the first Ba site, Ba is bonded in a body-centered cubic geometry to four equivalent Cs and four equivalent Ba atoms. All Ba–Ba bond lengths are 4.52 Å. In the second Ba site, Ba is bonded in a distorted body-centered cubic geometry to six equivalent Cs and eight equivalent Ba atoms.

36 MATERIALS SCIENCE↗