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Liao, W.*; Ito, Kojiro*; Abe, Shinichiro; Mitsuyama, Yukio*; Hashimoto, Masanori*
IEEE Transactions on Nuclear Science, 68(6), p.1228 - 1234, 2021/06
Times Cited Count：2 Percentile：31.78(Engineering, Electrical & Electronic)Secondary cosmic-ray neutron-induced single event upset (SEU) is a cause of soft errors on micro electronic devices. Multiple cell upsets (MCUs) are particularly serious problems since it is difficult to recover MCUs. In this study, we have performed irradiation tests of neutrons on 65-nm bulk SRAM at the national metrology institute of Japan (NMIJ) in Advanced Industrial Science and Technology (AIST) and measured SEU cross sections and MCU cross sections to investigate the effect on neutrons with the energies below 10 MeV on soft errors. It was found that SEU cross sections change drastically around 6 MeV. The proportion of MCU to total events does not change very much over the wide range of neutron energy. We also analyzed the total soft error rate (SER) of SEU and MCU by folding the neutron energy-dependent cross section and the flux spectra of the terrestrial neutron at New York and Tokyo. The calculated result indicates that the SER originating from the low-energy neutrons below 10 MeV is mostly negligible in the terrestrial environment.
Ota, Ryosuke*; Mitsuyama, Kazuaki*; Tachi, Yukio; Yotsuji, Kenji*; Sato, Tomofumi*; Sato, Hisao*; Martin, A.*
no journal, ,
The radionuclide migration model representing heterogeneities in distributions of minerals and pores was developed for Grimsel granodiorite. This model was applied to quantify the impact of heterogeneities on radionuclide migration and was validated by comparing with the measured data.
Yotsuji, Kenji*; Tachi, Yukio; Mitsuyama, Kazuaki*
no journal, ,
In the geological disposal of radioactive wastes, clay-sand mixed media play a key role in the barrier system, and a quantitative understanding of the radionuclide diffusion behavior in these media is important for safety assessment. In this paper, structural models of clay-sand mixed media were developed, and radionuclides were randomly walked in the structural models to simulate radionuclide migration. At that time, the volume fraction of sand was systematically changed, and then the critical behavior of the structural factors of the medium was evaluated.
