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Journal Articles

Consideration of creep relaxation initial stress setting method used to inelastic analysis for fast reactor components design

Noi, Hiromi*; Watanabe, Sota*; Kubo, Koji*; Okajima, Satoshi; Ando, Masanori

Nihon Kikai Gakkai M&M 2023 Zairyo Rikigaku Kanfarensu Koen Rombunshu (Internet), p.CL0712_1 - CL0712_5, 2023/09

no abstracts in English

Journal Articles

A Terrestrial SER Estimation Methodology Based on Simulation Coupled With One-Time Neutron Irradiation Testing

Abe, Shinichiro; Hashimoto, Masanori*; Liao, W.*; Kato, Takashi*; Asai, Hiroaki*; Shimbo, Kenichi*; Matsuyama, Hideya*; Sato, Tatsuhiko; Kobayashi, Kazutoshi*; Watanabe, Yukinobu*

IEEE Transactions on Nuclear Science, 70(8, Part 1), p.1652 - 1657, 2023/08

Single event upsets (SEUs) caused by neutrons is a reliability problem for microelectronic devices in the terrestrial environment. Acceleration tests using white neutron beam provide realistic soft error rates (SERs), but only a few facilities can provide white neutron beam in the world. If single-source irradiation applicable to diverse neutron source can be utilized for the evaluation of the SER in the terrestrial environment, it contributes to solve the shortage of beam time. In this study, we investigated the feasibility of the SER estimation in the terrestrial environment by any one of these measured data with the SEU cross sections obtained by PHITS simulation. It was found that the SERs estimated by our proposed method are within a factor of 2.7 of that estimated by the Weibull function. We also investigated the effect of simplification which reduce the computational cost in simulation to the SER estimation.

Journal Articles

Confirmation of the sustainability of decontamination effects in public facilities and prediction of future air dose rates

Kusakabe, Kazuaki*; Watanabe, Masanori; Nishiuchi, Masashi*; Yamasaki, Takuhei*; Inoue, Hiromi*

Kankyo Hoshano Josen Gakkai-Shi, 11(1), p.15 - 23, 2023/03

The spread of radioactive materials caused by the Fukushima Daiichi Nuclear Power Plant accident that occurred in March 2011 contaminated a wide area that includes Fukushima Prefecture. Although air dose rates in Fukushima Prefecture have been steadily decreasing because of decontamination and the physical decay of radioactive materials, it is important to confirm the sustainability of decontamination effects in living areas and to predict future trends in air dose rates to reassure residents who are concerned regarding radiation exposure. This report aims to confirm the sustainability of the decontamination effects in public facilities after decontamination on a continuous and detailed basis, and to verify whether the future transition in air dose rates can be predicted using existing model. The air dose rates in public facilities after decontamination were measured via fixed-point and walking surveys, and the changes in air dose rates were clarified quantitatively for each facility. The measured values were compared with values obtained using existing model, and prediction accuracy was considered. The results showed that there was no evident recontamination after decontamination at any of the surveyed facilities, indicating that the decontamination effects were sustained. It was also confirmed that future trends in air dose rates at the facilities after decontamination could be accurately predicted by existing model. Key words: air dose rate, decontamination, future prediction, public facilities.

Journal Articles

Multi-scale turbulence simulation suggesting improvement of electron heated plasma confinement

Maeyama, Shinya*; Watanabe, Tomohiko*; Nakata, Motoki*; Nunami, Masanori*; Asahi, Yuichi; Ishizawa, Akihiro*

Nature Communications (Internet), 13, p.3166_1 - 3166_8, 2022/06

 Times Cited Count:7 Percentile:92.8(Multidisciplinary Sciences)

Turbulent transport is a key physics process for confining magnetic fusion plasma. Recent theoretical and experimental studies of existing fusion experimental devices revealed the existence of cross-scale interactions between small (electron)-scale and large (ion)-scale turbulence. Since conventional turbulent transport modelling lacks cross-scale interactions, it should be clarified whether cross-scale interactions are needed to be considered in future experiments on burning plasma, whose high electron temperature is sustained with fusion-born alpha particle heating. Here, we present supercomputer simulations showing that electron scale turbulence in high electron temperature plasma can affect the turbulent transport of not only electrons but also fuels and ash. Electron-scale turbulence disturbs the trajectories of resonant electrons responsible for ion-scale micro-instability and suppresses large-scale turbulent fluctuations. Simultaneously, ion-scale turbulent eddies also suppress electron-scale turbulence. These results indicate a mutually exclusive nature of turbulence with disparate scales. We demonstrate the possibility of reduced heat flux via cross-scale interactions.

Journal Articles

Impact of the angle of incidence on negative muon-induced SEU cross sections of 65-nm Bulk and FDSOI SRAMs

Liao, W.*; Hashimoto, Masanori*; Manabe, Seiya*; Watanabe, Yukinobu*; Abe, Shinichiro; Tampo, Motonobu*; Takeshita, Soshi*; Miyake, Yasuhiro*

IEEE Transactions on Nuclear Science, 67(7), p.1566 - 1572, 2020/07

 Times Cited Count:0 Percentile:0.01(Engineering, Electrical & Electronic)

Muon-induced single event upset (SEU) is predicted to increase with technology scaling. The angle of incidence of terrestrial muons is not always perpendicular to the chip surface. Consequently, the impact of the angle of incidence of muons on SEUs should be evaluated. This study conducts negative muon irradiation tests on bulk SRAM and FDSOI SRAM at two angles of incidence: 0 degree (vertical) and 45 degree (tilted). The tilted incidence drifts the muon energy peak to a higher energy. Moreover, the SEU characteristics (i.e., such as the voltage dependences of the SEU cross sections and multiple cells upset patterns) between the vertical and tilted incidences are similar.

Journal Articles

Measurement of single-event upsets in 65-nm SRAMs under irradiation of spallation neutrons at J-PARC MLF

Kuroda, Junya*; Manabe, Seiya*; Watanabe, Yukinobu*; Ito, Kojiro*; Liao, W.*; Hashimoto, Masanori*; Abe, Shinichiro; Harada, Masahide; Oikawa, Kenichi; Miyake, Yasuhiro*

IEEE Transactions on Nuclear Science, 67(7), p.1599 - 1605, 2020/07

 Times Cited Count:2 Percentile:46.37(Engineering, Electrical & Electronic)

Soft errors induced by terrestrial radiation in semiconductor devices have been of concern from the viewpoint of their reliability. Generally, to evaluate the soft error rates (SERs), neutron irradiation tests are performed at neutron facility. We have performed SER measurement for the 65-nm bulk SRAM and the FDSOI SRAM at RCNP in Osaka University and CYRIC in Tohoku University. In this study, we performed SER measurement for the same devices at BL10 in J-PARC MLF. The increasing rate of SER by reducing the supply voltage at J-PARC BL10 is larger than those obtained at RCNP and CYRIC. From PHITS simulation, the cause of this difference can be explained by the influence of the protons generated by neutron elastic scattering with hydrogen atoms in the package resin.

Journal Articles

Impact of hydrided and non-hydrided materials near transistors on neutron-induced single event upsets

Abe, Shinichiro; Sato, Tatsuhiko; Kuroda, Junya*; Manabe, Seiya*; Watanabe, Yukinobu*; Liao, W.*; Ito, Kojiro*; Hashimoto, Masanori*; Harada, Masahide; Oikawa, Kenichi; et al.

Proceedings of IEEE International Reliability Physics Symposium (IRPS 2020) (Internet), 6 Pages, 2020/04

 Times Cited Count:1 Percentile:64.88

Single event upsets (SEUs) caused by neutrons have been recognized as a serious reliability problem for microelectronic devices on the ground level. In our previous work, it was found that hydride placed in front of the memory chip has considerably impact on SEU cross sections because H ions generated via elastic scattering of neutrons with hydrogen atoms are only emitted in a forward direction. In this study, the effect of components neighboring transistors on neutron-induced SEUs was investigated for 65-nm bulk SRAMs by using PHITS. It was found that the shape of the SEU cross section around few MeV comes from the thickness and the position of components placed in front of transistors when that components do not contains hydrogen atoms. By considering components adjoin memory cells in the test board used in the simulation, measured data at J-PARC BL10 were reproduced well. In addition, it was found that the effect of components neighboring transistors on neutron-induced SERs does not negligible in terrestrial environment.

Journal Articles

Characterizing SRAM and FF soft error rates with measurement and simulation

Hashimoto, Masanori*; Kobayashi, Kazutoshi*; Furuta, Jun*; Abe, Shinichiro; Watanabe, Yukinobu*

Integration, 69, p.161 - 179, 2019/11

Soft error originating from cosmic ray is a serious concern for reliability demanding applications. Device miniaturization and lower voltage operation degrade the immunity of SRAM and flip-flops, and then soft error countermeasures will be demanded in more and more products. This paper characterizes and discusses soft error rates of SRAM and flip-flops in the terrestrial environment with the results of investigation for soft error phenomena by measurements and simulations.

Journal Articles

Impact of irradiation side on neutron-induced single-event upsets in 65-nm Bulk SRAMs

Abe, Shinichiro; Liao, W.*; Manabe, Seiya*; Sato, Tatsuhiko; Hashimoto, Masanori*; Watanabe, Yukinobu*

IEEE Transactions on Nuclear Science, 66(7, Part 2 ), p.1374 - 1380, 2019/07

 Times Cited Count:6 Percentile:62.49(Engineering, Electrical & Electronic)

Single event upsets (SEUs) caused by secondary cosmic-ray neutrons have recognized as a serious reliability problem for microelectronic devices. Acceleration tests at neutron facilities are convenient to validate soft error rates (SERs) quickly, but some corrections caused from measurement conditions are required to derive realistic SERs at actual environment or to compare other measured data. In this study, the effect of irradiation side on neutron-induced SEU cross sections was investigated by performing neutron transport simulation using PHITS. SERs for 65-nm bulk CMOS SRAMs are estimated using the sensitive volume model. It was found from simulation that SERs for the sealant side irradiation are 30-50% larger than those for the board side irradiation. This difference comes from the difference of production yield and angular distribution of secondary H and He ions, which are the main cause of SEUs. Thus the direction of neutron irradiation should be reported when the result of acceleration tests are published. This result also indicates that SERs can be reduced by equipping device with sealant side facing downward.

Journal Articles

Similarity analysis on neutron- and negative muon-induced MCUs in 65-nm bulk SRAM

Liao, W.*; Hashimoto, Masanori*; Manabe, Seiya*; Abe, Shinichiro; Watanabe, Yukinobu*

IEEE Transactions on Nuclear Science, 66(7), p.1390 - 1397, 2019/07

Multiple-cell upset (MCU) in static random access memory (SRAM) is a major concern in radiation effects on microelectronic devices since it can spoil error correcting codes. Neutron-induced MCUs have been characterized for terrestrial environment. On the other hand, negative muon-induced MCUs were recently reported. Neutron- and negative muon-induced MCUs are both caused by secondary ions, and hence, they are expected to have some similarity. In this paper, we compare negative muon- and neutron-induced MCUs in 65-nm bulk SRAMs at the irradiation experiments using spallation and quasi-monoenergetic neutrons and monoenergetic negative muons. The measurement results show that the dependencies of MCU event cross section on operating voltage are almost identical. The Monte Carlo simulation is conducted to investigate the deposited charge. The distributions of deposited charge obtained by the simulation are consistent with the above-mentioned experimental observations.

Journal Articles

Estimation of muon-induced SEU rates for 65-nm bulk and UTBB-SOI SRAMs

Manabe, Seiya*; Watanabe, Yukinobu*; Liao, W.*; Hashimoto, Masanori*; Abe, Shinichiro

IEEE Transactions on Nuclear Science, 66(7), p.1398 - 1403, 2019/07

Cosmic ray-induced soft errors have been recognized as a major threat for electronics used at ground level. Recently, cosmic-ray muon-induced soft errors have received much attention due to the reduction of soft error immunity on SRAMs. In the previous studies, muon-induced soft error rates (SERs) for various technology devices were predicted with only the positive muon irradiation tests and simulation. In this paper, the muon-induced SEU rates for the 65-nm bulk and UTBB-SOI SRAMs are estimated by using the experimental data of both negative and positive muons. The experimental results showed that the negative muon SEU cross sections for the bulk SRAM are significantly larger than those for the UTBB-SOI. Estimation of muon-induced SEU rates at ground level was performed using PHITS with the experimental results. The muon-induced SER on the first floor of the building was estimated to be at most 10% of the neutron-induced SER on the same floor.

Journal Articles

Implementation of a gyrokinetic collision operator with an implicit time integration scheme and its computational performance

Maeyama, Shinya*; Watanabe, Tomohiko*; Idomura, Yasuhiro; Nakata, Motoki*; Nunami, Masanori*

Computer Physics Communications, 235, p.9 - 15, 2019/02

 Times Cited Count:5 Percentile:46.98(Computer Science, Interdisciplinary Applications)

We have implemented the Sugama collision operator in the gyrokinetic Vlasov simulation code, GKV, with an implicit time-integration scheme. The new method is versatile and independent of the details of the linearized collision operator, by means of an operator splitting, an implicit time integrator, and an iterative Krylov subspace solver. Numerical tests demonstrate stable computation over the time step size restricted by the collision term. An efficient implementation for parallel computation on distributed memory systems is realized by using the data transpose communication, which makes the iterative solver free from inter-node communications during iteration. Consequently, the present approach achieves enhancement of computational efficiency and reduction of computational time to solution simultaneously, and significantly accelerates the total performance of the application.

Journal Articles

Negative and positive muon-induced single event upsets in 65-nm UTBB SOI SRAMs

Manabe, Seiya*; Watanabe, Yukinobu*; Liao, W.*; Hashimoto, Masanori*; Nakano, Keita*; Sato, Hikaru*; Kin, Tadahiro*; Abe, Shinichiro; Hamada, Koji*; Tampo, Motonobu*; et al.

IEEE Transactions on Nuclear Science, 65(8), p.1742 - 1749, 2018/08

 Times Cited Count:6 Percentile:63.44(Engineering, Electrical & Electronic)

Recently, the malfunction of microelectronics caused by secondary cosmic-ray muon is concerned as semiconductor devices become sensitive to radiation. In this study, we have performed muon irradiation testing for 65-nm ultra-thin body and thin buried oxide (UTBB-SOI) SRAMs in the Japan Proton Accelerator Research Complex (J-PARC), in order to investigate dependencies of single event upset (SEU) cross section on incident muon momentum and supply voltage. It was found that the SEU cross section by negative muon are approximately two to four times larger than those by positive muon in the momentum range from 35 MeV/c to 39 MeV/c. The supply voltage dependence of muon-induced SEU cross section was measured with the momentum of 38 MeV/c. SEU cross sections decrease with increasing supply voltage, but the decreasing of SEU cross section by negative muon is gentler than that by positive muon. Experimental data of positive and negative muon irradiation with the momentum of 38 MeV/c were analyzed by PHITS. It was clarified that the negative muon capture causes the difference between the SEU cross section by negative muon and that by positive muon.

Journal Articles

Measurement and mechanism investigation of negative and positive muon-induced upsets in 65-nm Bulk SRAMs

Liao, W.*; Hashimoto, Masanori*; Manabe, Seiya*; Watanabe, Yukinobu*; Abe, Shinichiro; Nakano, Keita*; Sato, Hikaru*; Kin, Tadahiro*; Hamada, Koji*; Tampo, Motonobu*; et al.

IEEE Transactions on Nuclear Science, 65(8), p.1734 - 1741, 2018/08

 Times Cited Count:12 Percentile:82.06(Engineering, Electrical & Electronic)

Soft error induced by secondary cosmic-ray muon is concerned since susceptibility of semiconductor device to soft error increases with the scaling of technology. In this study, we have performed irradiation tests of muons on 65-nm bulk CMOS SRAM in the Japan Proton Accelerator Research Complex (J-PARC) and measured soft error rate (SER) to investigate mechanism of muon-induced soft errors. It was found that SER by negative muon increases above 0.5 V supply voltage, although SER by positive muon increases monotonically as the supply voltage lowers. SER by negative muon also increases with forward body bias. In addition, negative muon causes large multiple cell upset (MCU) of more than 20 bits and the ratio of MCU events to all the events is 66% at 1.2V supply voltage. These tendencies indicate that parasitic bipolar action (PBA) is highly possible to contribute to SER by negative muon. Experimental data are analyzed by PHITS. It was found that negative muon can deposit larger charge than positive muon, and such events that can deposit large charge may trigger PBA.

JAEA Reports

Research of the tasks on risk communication enforcement in fiscal year 2015 (Contract research)

Tanaka, Masaru*; Aoyama, Isao*; Ishizaka, Kaoru*; Ohata, Yuki*; Fukuike, Iori*; Kawase, Keiichi; Watanabe, Masanori; Tokizawa, Takayuki; Miyagawa, Hiroshi*; Ishimori, Yuu

JAEA-Research 2017-003, 65 Pages, 2017/06

JAEA-Research-2017-003.pdf:2.92MB

JAEA Ningyo-toge Environmental Engineering Center and Fukushima Environmental Safety Center have same challenges in risk communication. As reference, similar domestic cases were investigated by our two Centers, and requirements for building long-term relationship were clarified. As follows; (1) Develop new relationship with various stakeholders in the region. (2) Make better use of existing resources (personnel, land and facilities, etc.). (3) Make a concerted effort to create new values with local stakeholders. (4) Make an opportunity which local stakeholders confirm safety and build confidence to the project. These efforts will enhance the opportunities for operators and residents to learn about environment management and environmental protection.

Journal Articles

Cross-scale interactions between turbulence driven by electron and ion temperature gradients via sub-ion-scale structures

Maeyama, Shinya*; Watanabe, Tomohiko*; Idomura, Yasuhiro; Nakata, Motoki*; Ishizawa, Akihiro*; Nunami, Masanori*

Nuclear Fusion, 57(6), p.066036_1 - 066036_10, 2017/05

 Times Cited Count:13 Percentile:63.66(Physics, Fluids & Plasmas)

Multi-scale plasma turbulence including electron and ion temperature gradient (ETG/ITG) modes has been investigated by means of electromagnetic gyrokinetic simulations. Triad transfer analyses on nonlinear mode coupling reveal cross-scale interactions between electron and ion scales. One of the interactions is suppression of electron-scale turbulence by ion- scale turbulence, where ITG-driven short-wavelength eddies act like shear flows and suppress ETG turbulence. Another cross-scale interaction is enhancement of ion-scale turbulence in the presence of electron-scale turbulence. This is caused via short-wavelength zonal flows, which are created by the response of passing kinetic electrons in ITG turbulence, suppress ITG turbulence by their shearing, and are damped by ETG turbulence. In both cases, sub-ion-scale structures between electron and ion scales play important roles in the cross-scale interactions.

JAEA Reports

Survey results for the transition of the air dose rate after the Cabinet Office decontamination model demonstration project; 1st-11th survey results summary (Contract research)

Kawase, Keiichi; Kitano, Mitsuaki; Watanabe, Masanori; Yoshimura, Shuichi; Kikuchi, Shiro; Nishino, Katsumi*

JAEA-Review 2017-006, 173 Pages, 2017/03

JAEA-Review-2017-006.pdf:35.6MB
JAEA-Review-2017-006-appendix(CD-ROM).zip:0.52MB

Survey of a transition of the air and surface dose rate was conducted for the area where the Cabinet Office decontamination model demonstration project was implemented. The area includes 15 districts in 9 municipalities identified by the Ministry of the Environment. We investigated 11 times from October, 2012 to October, 2015. Measurement of the air dose rate in this study was carried out in two methods using the fixed-point measurement and gamma plotter H using a NaI scintillation survey meter etc. As fixed-point measurement, set measurement point in the first survey for (fixed point), it was subjected to measurement of the surface dose rate to continue (1cm height) and space dose rate (1m height). In addition surface specific dose rate distribution measurement using a gamma plotter H (5cm and 1m height) was also performed together. As a result of the fixed-point measurement and gamma plotter H surface measurements, space dose rate from the first survey to the 11th survey shows the downward trend. We consider that there is no movement of radioactive pollutants from outside decontamination model project area into decontamination model project area.

JAEA Reports

Survey on evacuation facilities in case of nuclear emergency in Shimane prefecture (Contract research)

Takahara, Shogo; Watanabe, Masatoshi; Oguri, Tomomi; Kimura, Masanori; Hirouchi, Jun; Munakata, Masahiro; Homma, Toshimitsu

JAEA-Data/Code 2016-016, 65 Pages, 2017/02

JAEA-Data-Code-2016-016.pdf:2.32MB

We surveyed on structural and material data on 22 facilities which are listed in local disaster management plan in Matsue city. These facilities can be divided into educational facilities, communal facilities and gymnastic hall. Height and floor-area of rooms, as well as window-area were collected as the structural data. We also collected information on constructional materials, and density of those. In addition, mass-thicknesses of the constructional materials were evaluated based on our surveys, and compared to the previous studies which were made in Japan, U.S., and European countries. Consequently, it was found that there is no significant difference of mass-thickness of constructional materials between the results of our surveys and the previous studies. However, for gymnastic hall, since thin metal plates are used for roofs, we can point out that the mass-thickness of roofs are much lower than those for other concrete facilities and clay tile roofing wooden houses.

Journal Articles

A Screening method for prevention of ratcheting strain derived from movement of temperature distribution

Okajima, Satoshi; Wakai, Takashi; Ando, Masanori; Inoue, Yasuhiro*; Watanabe, Sota*

Journal of Pressure Vessel Technology, 138(5), p.051204_1 - 051204_6, 2016/10

 Times Cited Count:2 Percentile:13.59(Engineering, Mechanical)

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2014

Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Takeyasu, Masanori; Mizutani, Tomoko; Isozaki, Tokuju*; Nagaoka, Mika; Hokama, Tomonori; Yokoyama, Hiroya; Nishimura, Tomohiro; et al.

JAEA-Review 2015-034, 175 Pages, 2016/03

JAEA-Review-2015-034.pdf:8.13MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2014 to March 2015. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co. in March 2011.

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