3D Analysis of Helium-3 Nanobubbles in Palladium Aged under Tritium by Electron Tomography

Abstract

A 3D analysis at the nanoscale has been used to characterize helium-3 nanobubbles in palladium powders aged several years under tritium to assess their structural characteristics and spatial distribution. These helium-3 nanobubbles are formed by tritium radioactive decay and exhibit diameters centered around 2.5 nm. Scanning transmission electron microscopy (STEM) has been used to acquire tomographic series on typical zones of the macroscopic specimen containing helium nanobubbles. Electron tomography data treatments have been achieved, allowing 3D structural analysis of helium-3 nanobubbles. For the first time, interdistances between bubbles have been determined with a mean value between 8 and 10 nm. The swelling of the aged material varies between 8 and 18%, in agreement with macroscopic measurements and modeling.

Aging of Pd under tritium: Influence of 3He generation and associated mechanisms

“…When 3 He release step begins, Equations ( 3) and ( 4) govern material evolution: After several tests on input data (Figures SM 9 and SM 10 in Supplementary Materials), the best agreement between calculation and experimental result (on output data: helium release/storage) is obtained for S=20% and ρHe=100 He/nm 3 or S=25% and ρHe=80 He/nm 3 . These swelling (S) and 3 He density (ρHe) values are very close from experimental measurements by tomography/pycnometry (swelling) (16,23) and EELS/NMR ( 3 He density) (4,6). The result of one calculation is reported in Figure 5.…”

Less-than-One Shot 3D Segmentation Hijacking a Pre-trained Space-Time Memory Network

“…However, the resulting data contain noisy reconstruction artifacts because the number of projections is limited, and their alignment remains a challenging task [25] (Figure 1). Thus, standard segmentation methods often fail [8], requiring the input of an expert to achieve a good segmentation [9,13,26].…”