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Journal Articles

Development of cesium-free mineralization for decontamination and reuse of radioactive contaminated soil in Fukushima

Shimoyama, Iwao; Honda, Mitsunori; Kogure, Toshihiro*; Baba, Yuji; Hirao, Norie*; Okamoto, Yoshihiro; Yaita, Tsuyoshi; Suzuki, Shinichi

Photon Factory News, 35(1), p.17 - 22, 2017/05

We introduce Cs-free mineralization (CFM) for Cs removal and reuse of radioactive-contaminated soil in Fukushima and report recent work conducted in the BL27A beamline in Photon Factory. In this work, we investigated compositional and structural changes of Cs-sorbed weathered biotite (WB) before and after heating treatment with addition of NaCl-CaCl$$_{2}$$ salts under low-pressure condition, to study Cs desorption mechanism from clay minerals. X-ray fluorescence spectroscopy clarified that almost all Cs and K were removed with the salts at 700 $$^{circ}$$C. On the other hand, Ca increased with heating temperature. X-ray diffraction and transmission electron microscopy analysis clarified that phase transitions from WB to some Ca-rich silicate minerals, e.g., augite, were caused by the heating treatment with the salt. Based on these results, CFM is proposed for Cs removal utilizing the mechanism in which large monovalent cations are discharged with accompanying the phase transition. We also discuss the role of Cl in this reaction showing chemical bonding change of Cl observed using X-ray absorption spectroscopy in the early stage of the chemical reaction.

Journal Articles

Desorption behavior of Cs from clay minerals by thermal heating in a vacuum; Analyses by thermal desorption spectroscopy and synchrotron radiation X-ray photoelectron spectroscopy

Hirao, Norie; Shimoyama, Iwao; Baba, Yuji; Izumi, Toshinori; Okamoto, Yoshihiro; Yaita, Tsuyoshi; Suzuki, Shinichi

Bunseki Kagaku, 65(5), p.259 - 266, 2016/05

 Times Cited Count:4 Percentile:17.42(Chemistry, Analytical)

After the Fukushima nuclear plant accident, radiocesium was strongly fixed to clay minerals in the soil. Some dry methods with heating are being developed to remove radiocesium from the soil. In this work, we propose a new dry method that combines heat treatment in vacuum and molten salts to reduce the processing temperature in dry methods. Vermiculite saturated with non-radioactive Cs was heated in vacuum, and Cs contents in the vermiculite were compared before and after heating using X-ray photoelectron spectroscopy. Approximately 40% of cesium were removed by heating at 800$$^{circ}$$C for three minutes when only vermiculite was heated. Approximately 70% of cesium were removed by heating at 450$$^{circ}$$C for three minutes when vermiculite was heated with NaCl/CaCl$$_{2}$$ mixed salts. Based on these results, this method is expected to reduce temperature and increase efficiency on dry methods for cesium removal from clay minerals.

Journal Articles

Current status and problems of computer codes for nuclear safety evaluation

Suyama, Kenya; Hirao, Yoshihiro*; Sakamoto, Hiroki*

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 57(12), p.787 - 791, 2015/12

In the measures to pursue the world's highest level of safety of the nuclear installations, it is required to maintain the technical revel of the safety analyses codes as higher as possible. Because many of them were introduced from US at the initial phase of the nuclear energy introduction, development of computer codes and relevant tools in Japan have not been continued successfully. Accordingly, many old US-oriented code has been used. This manuscript presents the current status and the problems of computer codes for nuclear safety evaluation, and a scheme to introduce the computer codes of Japan, which in-cooperate the latest knowledge, in the scene of nuclear safety regulation and practical purpose.

Journal Articles

Contracted interlayer distance in graphene/sapphire heterostructure

Entani, Shiro; Antipina, L. Y.*; Avramov, P.*; Otomo, Manabu*; Matsumoto, Yoshihiro*; Hirao, Norie; Shimoyama, Iwao; Naramoto, Hiroshi*; Baba, Yuji; Sorokin, P. B.*; et al.

Nano Research, 8(5), p.1535 - 1545, 2015/05

 Times Cited Count:21 Percentile:70.01(Chemistry, Physical)

Journal Articles

Low-pressure sublimation method for cesium decontamination of clay minerals

Shimoyama, Iwao; Hirao, Norie; Baba, Yuji; Izumi, Toshinori; Okamoto, Yoshihiro; Yaita, Tsuyoshi; Suzuki, Shinichi

Clay Science, 18(3), p.71 - 77, 2014/09

no abstracts in English

Journal Articles

Suppression of heavy-ion induced current in SOI device

Ogura, Shunta*; Komiyama, Takahiro*; Takahashi, Yoshihiro*; Makino, Takahiro; Onoda, Shinobu; Hirao, Toshio*; Oshima, Takeshi

Proceedings of 10th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-10) (Internet), p.127 - 129, 2012/12

We have investigated the transient current in a SOI p$$^+$$n junction diode induced by single heavy-ions. The amount of radiation induced total collected charge exceeds the generated charge in active SOI layer because some of generated charge in handle substrate is collected through a BOX layer by displacement current. The displacement current is caused by the charges collected at surface of handle substrate due to an electric field in depletion layer. In this paper, we show that the amount of collected charge can be suppressed by reducing the width of depletion layer at the surface of handle substrate.

Journal Articles

Heavy-ion induced current in SOI junction diode

Takahashi, Yoshihiro*; Takeyasu, Hidenori*; Okazaki, Yuji*; Hirao, Toshio; Onoda, Shinobu; Oshima, Takeshi

Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.173 - 175, 2010/10

no abstracts in English

Journal Articles

Ion beam breeding of summer-to-autumn flowering chrysanthemum "Floral-Yuka"

Shirao, Tsukasa*; Nagatani, Takeshi*; Nozawa, Shigeki; Hase, Yoshihiro; Tanaka, Atsushi; Narumi, Issei

JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 79, 2009/12

no abstracts in English

Journal Articles

Change in ion beam induced current from Si metal-oxide-semiconductor capacitors after $$gamma$$-ray irradiation

Oshima, Takeshi; Onoda, Shinobu; Hirao, Toshio; Takahashi, Yoshihiro*; Vizkelethy, G.*; Doyle, B. L.*

AIP Conference Proceedings 1099, p.1014 - 1017, 2009/03

Metal-Oxide-Semiconductor (MOS) capacitors were made on both n- and p-type Si substrates (n-MOS, and p-MOS). These MOS capacitors were irradiated with $$gamma$$-rays at a dose of 6.3 kGy (SiO$$_{2}$$) at room temperature. The capacitance-voltage characteristics for MOS capacitors were measured before and after irradiation. The flat band shift for n-MOS and p-MOS capacitors due to $$gamma$$-ray irradiation was -12.3 V and -15.2 V, respectively. As for the generation of interface traps, the values for n-MOS and p-MOS capacitors were estimated to be 0.5$$times$$10$$^{11}$$ and 1.7$$times$$10$$^{11}$$/cm$$^{2}$$, respectively. Transient Ion Beam Induced Current (TIBIC) obtained from these MOS capacitors were compared before and after $$gamma$$-ray irradiation. For n-MOS capacitors, the peak height of TIBIC signals decreased after $$gamma$$-ray irradiation. On the other hand, the peak height of TIBIC signals for p-MOS capacitors increased after $$gamma$$-ray irradiation. The applied bias dependence of the peak height of TIBIC signals for MOS capacitors irradiated with $$gamma$$-rays can be matched to that for ones before $$gamma$$-rays irradiation by shifting the voltage by -13 V for n-MOS capacitors and by -15 V for p-MOS capacitors. These voltage values are in good agreement with the flat band voltage shifts due to $$gamma$$-ray irradiation. Since flat band shift occurs due to the generation of positive charge trapped in gate oxide, the change in TIBIC signals observed for MOS capacitors due to $$gamma$$-ray irradiation can be interpreted in terms of positive charge generated in oxide.

Journal Articles

Total dose effects on heavy-ion induced gate current in MOS structure

Takahashi, Yoshihiro*; Fugane, Masaru*; Imagawa, Ryo*; Owaki, Akihiro*; Hirao, Toshio; Onoda, Shinobu; Oshima, Takeshi

JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 7, 2008/11

no abstracts in English

Journal Articles

Comparison of the experimental results with simulated results of charge induced in MOS FET by heavy-ion irradiation

Hirao, Toshio; Onoda, Shinobu; Takahashi, Yoshihiro*; Oshima, Takeshi

JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 6, 2008/11

no abstracts in English

Journal Articles

Ion beam breeding of sugarcane cultivar "Ni17"

Takenoshita, Yoshihisa*; Tojima, Futoshi*; Nishi, Hiroyuki*; Shirao, Tsukasa*; Nagatani, Takeshi*; Oe, Masakazu*; Hase, Yoshihiro; Narumi, Issei

JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 66, 2008/11

no abstracts in English

Journal Articles

Benchmarking for high-energy physics applications using by PHITS code

Matsuda, Norihiro; Iwamoto, Yosuke; Hirao, Yoshihiro; Sakamoto, Yukio; Niita, Koji*

Journal of Nuclear Science and Technology, 45(Suppl.5), p.97 - 100, 2008/06

 Times Cited Count:1 Percentile:10.65(Nuclear Science & Technology)

Particle and Heavy Ion Transport code System (PHITS) supports a broad range of research activities: radiation shielding and dosimetry, radiotherapy and space science as well as the high-energy physics. In this paper, various benchmark calculations based on high-energy collision experiments are carried out using PHITS code: particle production (positive and negative pion) on thin or thick targets (hydrogen, carbon and aluminum), and energy deposition in target (copper) or peripheral equipment (inner and outer absorber). On the whole, the good agreement between PHITS calculations and experimental data is shown for many cases.

Journal Articles

The Optimum dose of ion beam irradiation for growth of sugarcane

Tojima, Futoshi*; Takenoshita, Yoshihisa*; Shirao, Tsukasa*; Nagatani, Takeshi*; Oe, Masakazu*; Ueno, Keiichiro*; Hase, Yoshihiro; Tanaka, Atsushi

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 73, 2008/03

no abstracts in English

Journal Articles

Ion beam breeding of chrysanthemum cultivar "Sanyo-ohgon"

Shirao, Tsukasa*; Ueno, Keiichiro*; Minami, Tomohito*; Tanaka, Akira*; Imakiire, Seiro*; Hase, Yoshihiro; Tanaka, Atsushi

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 74, 2008/03

no abstracts in English

Journal Articles

The Electronic structures of fullerene/transition-metal hybrid material

Matsumoto, Yoshihiro; Sakai, Seiji; Naramoto, Hiroshi*; Hirao, Norie*; Baba, Yuji; Shimada, Toshihiro*; Sugai, Isamu; Takanashi, Koki; Maeda, Yoshihito

Materials Research Society Symposium Proceedings, Vol.1081 (Internet), 6 Pages, 2008/03

Recently, we have found the appearance of substantial MR ratio (80%) in a C$$_{60}$$/Co hybrid material. Such the MR ratio cannot be explained enough only by tunnel conduction through Co grains. Therefore, to obtain information about electronic structures of C$$_{60}$$/Co hybrid material is necessary. Absorption spectra of C$$_{60}$$Co are different from that of pristine C$$_{60}$$. In particular, peak intensity corresponding to $$pi$$ $$^*$$(LUMO) $$leftarrow$$ C 1s excitation of C$$_{60}$$Co is clearly attenuated. In addition, C 1s photoelectron peak of C$$_{60}$$Co slightly shifted to lower binding energy compared to that of pristine C$$_{60}$$. These results indicate that 3d electron of Co transfers to $$pi$$ $$^*$$ orbital of C$$_{60}$$ and new electronic states are formed in the C$$_{60}$$-Co compound. In fact, XPS spectra of valence excitation region also demonstrate the formation of hybrid orbital near the Fermi level due to the coupling of C$$_{60}$$ and Co.

Journal Articles

Heavy-ion induced current through an oxide layer

Takahashi, Yoshihiro*; Oki, Takahiro*; Nagasawa, Takaharu*; Nakajima, Yasuhito*; Kawanabe, Ryu*; Onishi, Kazunori*; Hirao, Toshio; Onoda, Shinobu; Mishima, Kenta; Kawano, Katsuyasu*; et al.

Nuclear Instruments and Methods in Physics Research B, 260(1), p.309 - 313, 2007/07

 Times Cited Count:4 Percentile:36.48(Instruments & Instrumentation)

no abstracts in English

Journal Articles

The Optimum dose of ion beam irradiation to tissue cultured of leaf explants for breeding sugarcane

Tojima, Futoshi*; Shirao, Tsukasa*; Ueno, Keiichiro*; Oe, Masakazu*; Yasuniwa, Makoto*; Hase, Yoshihiro; Tanaka, Atsushi

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 83, 2007/02

no abstracts in English

Journal Articles

Optimization for SEU/SET immunity on 0.15 $$mu$$m fully depleted CMOS/SOI digital logic devices

Makihara, Akiko*; Asai, Hiroaki*; Tsuchiya, Yoshihisa*; Amano, Yukio*; Midorikawa, Masahiko*; Shindo, Hiroyuki*; Kuboyama, Satoshi*; Onoda, Shinobu; Hirao, Toshio; Nakajima, Yasuhito*; et al.

Proceedings of 7th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-7), p.95 - 98, 2006/10

no abstracts in English

Journal Articles

Charge collected in Si MOS capacitors and SOI devices p$$^{+}$$n diodes due to heavy ion irradiation

Hirao, Toshio; Laird, J. S.; Onoda, Shinobu; Shibata, Toshihiko*; Wakasa, Takeshi; Yamakawa, Takeshi; Abe, Hiroshi; Takahashi, Yoshihiro*; Onishi, Kazunori*; Ito, Hisayoshi

Proceedings of the 6th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-6), p.105 - 109, 2004/10

no abstracts in English

75 (Records 1-20 displayed on this page)