Synchrotron-based analysis of spherical iron oxide particles found in Hiroshima Bay

Satou, Yukihiko   ; Endo, Satoru*; Akaji, Ryoga*; Shobu, Takahisa  ; Tominaga, Aki; Sumita, Takehiro*   

This study explores spherical iron oxide particles from Hiroshima Bay, once hypothesized to originate from the atomic bombing. Despite prior suggestions of high-temperature formation, no radioactive nuclides such as Cs or U were detected. Using synchrotron-based techniques developed for Fukushima microparticles, samples from Ujina Island were analyzed. X-ray computed tomography revealed large internal voids, and XRF/SEM-EDS showed Fe, Si, and Al as major constituents. Comparisons with welding splatter and fireworks indicated distinct structural and elemental differences. These findings suggest formation under extraordinary thermal conditions, with future XRD and SIMS analyses expected to further clarify their origin.