[2J09-20] Environmental Radiation

[2J11] Analysis of microscopic molten particles possibly originating from the atomic bomb collected from Hiroshima City

*Shoki Yoshimura¹, Tamaki Matsumura¹, Masato Morita¹, Tesuo Sakamoto¹, Rina Yamawaki², Ryouka Akazi², Satoru Endo², Yasuhito Igarashi³ (1. Kogakuin Univ., 2. Hiroshima Univ., 3. Kyoto Univ.)

Keywords:Mass spectrometry, Surface analysis, atomic bomb, Molten glass particles

In 2019, a peculiar glassy particle was discovered by Wannier et al. on the coast of Hiroshima . The particles were found to have undergone a high-temperature melting process, as they had internal cavities and were spherical in shape at several hundred micrometers. They were also found in large quantities on the shores of Hiroshima Bay, suggesting that they may have been part of the "black rain" that fell as rain from soil components and fission product materials that were rolled up by the shock and heat of the atomic bomb. However, since no radioisotopes have been detected in the individual particles, it has not been determined whether they originated from the A-bomb. Furthermore, since more than 70 years have passed since the A-bombing, it is difficult to analyze the radioactive materials. Therefore, in this study, we analyzed glass particles using focused ion beam time of flight mass spectrometry (FIB-TOF-SIMS), which is capable of elemental and isotopic imaging with high areal resolution.