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Journal Articles

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

 Times Cited Count:5 Percentile:62.37(Physics, Multidisciplinary)

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for $$^{107}$$Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.

Journal Articles

Proton order-disorder phenomena in a hydrogen-bonded rhodium-$$eta$$$$^{5}$$-semiquinone complex; A Possible dielectric response mechanism

Mitsumi, Minoru*; Ezaki, Kazunari*; Komatsu, Yuki*; Toriumi, Koshiro*; Miyato, Tatsuya*; Mizuno, Motohiro*; Azuma, Nobuaki*; Miyazaki, Yuji*; Nakano, Motohiro*; Kitagawa, Yasutaka*; et al.

Chemistry; A European Journal, 21(27), p.9682 - 9696, 2015/06

 Times Cited Count:6 Percentile:26.76(Chemistry, Multidisciplinary)

Journal Articles

On-site background measurements for the J-PARC E56 experiment; A Search for the sterile neutrino at J-PARC MLF

Ajimura, Shuhei*; Bezerra, T. J. C.*; Chauveau, E.*; Enomoto, T.*; Furuta, Hisataka*; Harada, Masahide; Hasegawa, Shoichi; Hiraiwa, T.*; Igarashi, Yoichi*; Iwai, Eito*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2015(6), p.063C01_1 - 063C01_19, 2015/06

 Times Cited Count:3 Percentile:32.69(Physics, Multidisciplinary)

The J-PARC E56 experiment aims to search for sterile neutrinos at the J-PARC Materials and Life Science Experimental Facility (MLF). In order to examine the feasibility of the experiment, we measured the background rates of different detector candidate sites, which are located at the third floor of the MLF, using a detector consisting of plastic scintillators with a fiducial mass of 500 kg. The gammas and neutrons induced by the beam as well as the backgrounds from the cosmic rays were measured, and the results are described in this article.

Journal Articles

LET dependency of human normal dermal cells survival in carbon ion irradiation

Yoshida, Yukari*; Mizohata, Kensuke*; Matsumura, Akihiko*; Isono, Mayu*; Yako, Tomoko*; Nakano, Takashi*; Funayama, Tomoo; Kobayashi, Yasuhiko; Kanai, Tatsuaki*

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 81, 2015/03

In the clinical application of carbon-ion (C-ion) radiation therapy in Japan, different RBE values of carbons have been used for clinical and biological endpoints. The biological RBE (bRBE) was estimated by a method that is based on the linear-quadratic (LQ) model, and was defined ${it in vitro}$ at the 10% surviving fraction of human salivary gland (HSG) tumor cells. However, many of biological parameters, that is, type of tissues, different sort of cells, oxygenation levels, and all, could affect radiosensitivity. Thus, normal human dermal fibroblasts (NHDF) cells were exposed to C-ion beams at Gunma University (10-80 keV/micrometer) and TIARA (108 and 158 keV/micrometer). The surviving fractions were analyzed with colony formation assays. The experimental RBE (eRBE) values were estimated from the radiation dose survival curve fitted by LQ model, and defined ${it in vitro}$.

Journal Articles

NHEJ repair rather than HR repair is the primary function to target to enhance radiosensitization at high LET values

Takahashi, Akihisa*; Kubo, Makoto*; Igarashi, Chie*; Yoshida, Yukari*; Funayama, Tomoo; Kobayashi, Yasuhiko; Nakano, Takashi*

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 82, 2015/03

DNA double-strand breaks (DSBs) induced by ionizing radiation pose a major threat to cell survival. The cell can respond to the presence of DSBs, through two major repair pathways: Homologous recombination (HR) and non-homologous end-joining (NHEJ). Higher levels of cell death are induced by high-LET radiation when compared to low-LET radiation, even at the same doses because of less effective or more inefficient DNA repair. In this study, we examine the effects of radiation with different LET values on DNA DSB repair and radiosensitivity. Wild-type cells and HR deficient (but NHEJ proficient) cells exhibited the high RBE values at LET values of 108 keV/$$mu$$ m. The RBE value for each cell type decreased with increasing LET values over 200 keV/$$mu$$m. Although NHEJ proficient cells had an almost constant SER value, NHEJ deficient cells showed a high SER value when compared to NHEJ proficient cells, even with increasing LET values.

Journal Articles

Effect of $$gamma$$-ray irradiation on corrosion of low alloy steel in neutral water

Yamamoto, Masahiro; Nakano, Junichi; Komatsu, Atsushi; Sato, Tomonori; Tsukada, Takashi

Proceedings of 19th International Corrosion Congress (19th ICC) (CD-ROM), 6 Pages, 2014/11

Corrosion protection of RPV and PCV is an important issue for the long term maintenance until the end of the decommissioning procedures. One of the uncertain factors for the issue is an effect of radioactivity on corrosion of LAS and CS. Corrosion tests using LAS and CS were conducted in $$gamma$$-rays irradiated condition. Oxygen and hydrogen peroxide concentrations in the water were measured after the tests. Corrosion test results indicated that the amounts of corrosion increased by $$gamma$$-rays irradiation both air and nitrogen atmosphere. And also corrosion amounts increased with $$gamma$$-ray dose rates. Electrochemical analyses indicated that cathodic reaction of Hydrogen peroxide was controlled by diffusion process. The measured diffusion constant of H$$_{2}$$O$$_{2}$$ was about 0.75 times to that of oxygen. From these results, it is estimated that corrosion of LAS and CS in $$gamma$$-ray irradiated condition was evaluated by the cathodic reduction reaction of oxidant.

Journal Articles

Nonhomologous end-joining repair plays a more important role than homologous recombination repair in defining radiosensitivity after exposure to high-LET radiation

Takahashi, Akihisa*; Kubo, Makoto*; Ma, H.*; Nakagawa, Akiko*; Yoshida, Yukari*; Isono, Mayu*; Kanai, Tatsuaki*; Ono, Tatsuya*; Furusawa, Yoshiya*; Funayama, Tomoo; et al.

Radiation Research, 182(3), p.338 - 344, 2014/09

 Times Cited Count:38 Percentile:87.69(Biology)

To clarify whether high-LET radiation inhibits all repair pathways or specifically one repair pathway, studies were designed to examine the effects of radiation with different LET values on DNA DSB repair and radiosensitivity. Embryonic fibroblasts bearing repair gene KO were exposed to X rays, carbon-, iron-, neon- and argon-ion beams. Cell survival was measured with colony-forming assays. The sensitization enhancement ratio (SER) values were calculated using the 10% survival dose of wild-type cells and repair-deficient cells. Cellular radiosensitivity was listed in descending order: double-KO cells $$>$$ NHEJ-KO cells $$>$$ HR-KO cells $$>$$ wild-type cells. Although HR-KO cells had an almost constant SER value, NHEJ-KO cells showed a high-SER value when compared to HR-KO cells, even with increasing LET values. These results suggest that with carbon-ion therapy, targeting NHEJ repair yields higher radiosensitivity than targeting homologous recombination repair.

Journal Articles

Effects of hydrazine addition and N$$_{2}$$ atmosphere on the corrosion of reactor vessel steels in diluted seawater under $$gamma$$-rays irradiation

Nakano, Junichi; Kaji, Yoshiyuki; Yamamoto, Masahiro; Tsukada, Takashi

Journal of Nuclear Science and Technology, 51(7-8), p.977 - 986, 2014/07

 Times Cited Count:3 Percentile:28.59(Nuclear Science & Technology)

Seawater was injected into the reactor cores in the Fukushima Daiichi Nuclear Power Station. Corrosion of reactor vessel steels is considered to progress. To evaluate durability of the reactor vessel steels, corrosion tests were conducted in diluted seawater at 50 $$^{circ}$$C under $$gamma$$-rays irradiation. 10 mg/L and 100 mg/L N$$_{2}$$H$$_{4}$$ were added to diluted seawater. Without addition of N$$_{2}$$H$$_{4}$$, weight loss in the vessel steels irradiated with the 0.2 kGy/h dose rate was comparable with those without irradiation and weight loss in the vessel steels irradiated with the 4.4 kGy/h dose rate was higher than those without irradiation. Under irradiation, weight loss in the vessel steels in diluted seawater containing N$$_{2}$$H$$_{4}$$ was comparable with that in diluted seawater without N$$_{2}$$H$$_{4}$$. When gas phase in the flask was replaced with N$$_{2}$$, weight loss in the vessel steels, and O$$_{2}$$ and H$$_{2}$$O$$_{2}$$ concentrations in the diluted seawater decreased.

Journal Articles

Increase in cell motility by carbon ion irradiation via the Rho signaling pathway and its inhibition by the ROCK inhibitor Y-27632 in lung adenocarcinoma A549 cells

Murata, Kazutoshi*; Noda, Shinei*; Oike, Takahiro*; Takahashi, Akihisa*; Yoshida, Yukari*; Suzuki, Yoshiyuki*; Ono, Tatsuya*; Funayama, Tomoo; Kobayashi, Yasuhiko; Takahashi, Takeo*; et al.

Journal of Radiation Research, 55(4), p.658 - 664, 2014/07

 Times Cited Count:15 Percentile:60.96(Biology)

The effect of carbon ion irradiation on cell motility through the Rho signaling pathway in the human lung adenocarcinoma cell line A549 was studied. At 48 h after irradiation, the cell motility of A549 cells became significantly greater, and the formation of protrusions significantly increased in cells irradiated with carbon ion. The observed increase in cell motility due to carbon ion irradiation was similar to that observed due to X-ray irradiation. Western-blot analysis showed that carbon ion irradiation increased P-MLC2-S19 expression compared with in unirradiated controls, while total MLC2 expression was unchanged. Exposure to a non-toxic concentration of Y-27632, a specific inhibitor of ROCK, reduced the expression of P-MLC2-S19 after C-ion irradiation, resulting in a significant reduction in migration. These data suggest that carbon irradiation increases cell motility in A549 cells via the Rho signaling pathway and that ROCK inhibition reduces that effect.

Journal Articles

Corrosion of carbon steel and low-alloy steel in diluted seawater containing hydrazine under $$gamma$$-rays irradiation

Nakano, Junichi; Yamamoto, Masahiro; Tsukada, Takashi

Nihon Genshiryoku Gakkai Wabun Rombunshi, 13(1), p.1 - 6, 2014/03

The seawater was injected into reactor cores of Units 1, 2 and 3 in the Fukushima Daiichi Nuclear Power Plant. To investigate effects of $$gamma$$ rays irradiation on corrosion of carbon steel and low alloy steel, corrosion tests were performed in the diluted seawater at 50 $$^{circ}$$C under $$gamma$$ rays irradiation with dose rates of 4.4 kGy/h and 0.2 kGy/h. Hydrazine (N$$_{2}$$H$$_{4}$$) was added to the diluted seawater. In the diluted seawater without N$$_{2}$$H$$_{4}$$, the weight losses of the steels irradiated with 0.2 kGy/h were similar to those of the unirradiated steels, and the weight losses of the steels irradiated with 4.4 kGy/h increased to approximate 1.7 times of those of the unirradiated steels. The weight losses of the steels irradiated in the diluted seawater containing N$$_{2}$$H$$_{4}$$ were similar to those in the diluted seawater without N$$_{2}$$H$$_{4}$$. When N$$_{2}$$ was introduced to gas phase in the flasks during $$gamma$$ rays irradiation, the weight losses of the steels decreased.

Journal Articles

Effects of temperature on stress corrosion cracking behavior of stainless steel and outer oxide distribution in cracks due to exposure to high-temperature water containing hydrogen peroxide

Nakano, Junichi; Sato, Tomonori; Kato, Chiaki; Yamamoto, Masahiro; Tsukada, Takashi; Kaji, Yoshiyuki

Journal of Nuclear Materials, 444(1-3), p.454 - 461, 2014/01

 Times Cited Count:1 Percentile:10.7(Materials Science, Multidisciplinary)

Cracking growth tests were conducted in high-temperature water containing hydrogen peroxide (H$$_{2}$$O$$_{2}$$) at 561 to 423 K to evaluate the effects of H$$_{2}$$O$$_{2}$$ on stress corrosion cracking (SCC) of stainless steel (SS) at temperature lower than the boiling water reactor (BWR) operating temperature. Small compact tension (CT) specimens were prepared from thermally sensitized type 304 SS. Despite the observation of only a small portion intergranular SCC (IGSCC) near the side groove of the CT specimen at 561 K in high-temperature water containing 100 ppb of H$$_{2}$$O$$_{2}$$, the IGSCC area expanded to the central region of the CT specimens at 423 and 453 K. Effects of H$$_{2}$$O$$_{2}$$ on SCC appeared intensely at temperature lower than the BWR operating temperature. To estimate the environment in the cracks, outer oxide distribution on the fracture surface and fatigue pre-crack were examined by laser Raman spectroscopy and thermal equilibrium calculation was performed.

Journal Articles

Morphology of stress corrosion cracking due to exposure to high-temperature water containing hydrogen peroxide in stainless steel specimens with different crevice lengths

Nakano, Junichi; Sato, Tomonori; Kato, Chiaki; Yamamoto, Masahiro; Tsukada, Takashi; Kaji, Yoshiyuki

Journal of Nuclear Materials, 441(1-3), p.348 - 356, 2013/10

 Times Cited Count:2 Percentile:21.27(Materials Science, Multidisciplinary)

Crack growth tests were performed in high-temperature water containing hydrogen peroxide (H$$_{2}$$O$$_{2}$$) to evaluate the relationships between the crevice structure and H$$_{2}$$O$$_{2}$$ on stress corrosion cracking (SCC) growth morphology of stainless steel (SS). Small compact tension (CT) specimens with different fatigue pre-crack lengths were prepared. 20$$sim$$300 ppb H$$_{2}$$O$$_{2}$$ was injected into the high-temperature water at 561 K. Intergranular SCC (IGSCC) was observed only near the side grooves of the CT specimens. Owing to pre-crack shortening, the IGSCC area expanded to the central region of the CT specimens. The effects of H$$_{2}$$O$$_{2}$$ on SS appeared intensely near the surfaces exposed to high levels of H$$_{2}$$O$$_{2}$$. The calculations for the percentage of H$$_{2}$$O$$_{2}$$ remaining showed that the effects of H$$_{2}$$O$$_{2}$$ flowed from both sides of the crack were more obvious than those flowed from the crack mouth.

Journal Articles

$$K^{ast 0}Sigma^+$$ photoproduction with evidence for the Kappa Meson Exchange at SPring-8/LEPS

Hwang, S. H.*; Hicks, K.*; Ahn, J. K.*; Nakano, Takashi*

Few-Body Systems, 54(7-10), p.1037 - 1041, 2013/08

 Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)

Journal Articles

Three-dimensional and multienergy $$gamma$$-ray simultaneous imaging by using a Si/CdTe Compton camera

Suzuki, Yoshiyuki*; Yamaguchi, Mitsutaka; Odaka, Hirokazu*; Shimada, Hirofumi*; Yoshida, Yukari*; Torikai, Kota*; Sato, Takahiro; Arakawa, Kazuo*; Kawachi, Naoki; Watanabe, Shigeki; et al.

Radiology, 267(3), p.941 - 947, 2013/06

 Times Cited Count:10 Percentile:42.69(Radiology, Nuclear Medicine & Medical Imaging)

Journal Articles

Development of a water purifier by EB-grafted fiber

Mikami, Takashi*; Nakano, Masanori*; Shibata, Takuya; Seko, Noriaki

Setsubi To Kanri, 47(4), p.95 - 99, 2013/04

no abstracts in English

Journal Articles

An Evaluation of three-dimensional imaging by use of Si/CdTe Compton cameras

Yamaguchi, Mitsutaka; Nagao, Yuto; Kawachi, Naoki; Fujimaki, Shu; Kamiya, Tomihiro; Odaka, Hirokazu*; Kokubun, Motohide*; Takeda, Shinichiro*; Watanabe, Shin*; Takahashi, Tadayuki*; et al.

Proceedings of 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), 3 Pages, 2013/00

Journal Articles

A New method for monitoring beam range by measuring low energy photons

Yamaguchi, Mitsutaka; Torikai, Kota*; Kawachi, Naoki; Shimada, Hirofumi*; Sato, Takahiro; Nagao, Yuto; Fujimaki, Shu; Kokubun, Motohide*; Watanabe, Shin*; Takahashi, Tadayuki*; et al.

Proceedings of 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), 2 Pages, 2013/00

Journal Articles

Applications and imaging techniques of a Si/CdTe Compton $$gamma$$-ray camera

Takeda, Shinichiro*; Ichinohe, Yuto*; Hagino, Koichi*; Odaka, Hirokazu*; Yuasa, Takayuki*; Ishikawa, Shinnosuke*; Fukuyama, Taro*; Saito, Shinya*; Sato, Tamotsu*; Sato, Goro*; et al.

Physics Procedia, 37, p.859 - 866, 2012/10

 Times Cited Count:16 Percentile:98.04

By using new Compton camera consisting of silicon double-sided strip detector (Si-DSD) and CdTe-DSD developed for the ASTRO-H mission, an experiment was conducted to study its feasibility for advanced hotspot monitoring. In addition to hotspot imaging already provided by commercial imaging systems, the identification of the variety of radioisotopes is realized thanks to the good energy resolution given by the semiconductor detectors. Three radioisotopes of $$^{133}$$Ba (356 keV), $$^{22}$$Na (511 keV) and $$^{137}$$Cs (662 keV) were individually imaged by applying event selection in the energy window and the $$gamma$$-ray images was correctly overlapped by an optical picture. The detection efficiency of 1.68$$times$$10$$^{-4}$$ (effective area: 1.7$$times$$10$$^{-4}$$ cm$$^2$$) and angular resolution of 3.8$$^{circ}$$ were obtained by stacking five detector modules for 662 keV $$gamma$$-ray. The higher detection efficiency required in a specific use can be achieved by stacking more detector modules.

Journal Articles

Influence of microstructure on IASCC growth behavior of neutron irradiated type 304 austenitic stainless steels in simulated BWR condition

Kaji, Yoshiyuki; Miwa, Yukio*; Shibata, Akira; Nakano, Junichi; Tsukada, Takashi; Takakura, Kenichi*; Nakata, Kiyotomo*

International Journal of Nuclear Energy Science and Engineering, 2(3), p.65 - 71, 2012/09

Crack growth rate (CGR) tests have been conducted with neutron irradiated compact tension (CT) specimens. The specimens were irradiated in the core region of the Japan Materials Testing Reactor (JMTR) in simulated BWR water environments at 288 $$^{circ}$$C from 0.37 to 5.55$$times$$10$$^{25}$$ n/m$$^{2}$$ (E$$>$$ 1 MeV) (0.62 to 9.2 dpa). The CGRs of base metals in high electrochemical corrosion potential (ECP) condition with 10 $$<$$ stress intensity factor, K $$<$$ 30 MPam$$^{1/2}$$, increased with increasing neutron fluence until 2 dpa and the CGRs were almost the same from 2 to 10 dpa. We investigated the influence of microstructure on CGR by microstructure observation and local strain measurement around the precipitate. This paper will discuss the relationship between CGR and microstructure, radiation hardening, radiation induced segregation.

Journal Articles

Effects of temperature on SCC propagation in high temperature water injected with hydrogen peroxide

Nakano, Junichi; Sato, Tomonori; Kato, Chiaki; Kaji, Yoshiyuki; Yamamoto, Masahiro; Tsukada, Takashi

Proceedings of 2012 Nuclear Plant Chemistry Conference (NPC 2012) (CD-ROM), 9 Pages, 2012/09

It has been reported that the corrosion behavior of stainless steels in high temperature water with hydrogen peroxide (H$$_{2}$$O$$_{2}$$) was different from those with O$$_{2}$$. To evaluate the effect of H$$_{2}$$O$$_{2}$$ on stress corrosion cracking (SCC), SCC growth tests were conducted in high temperature water injected with H$$_{2}$$O$$_{2}$$. In 100 ppb H$$_{2}$$O$$_{2}$$ at 561 K, an intergranular SCC (IGSCC) was observed only small portion of area near the side grooves of the CT specimen. In 100 ppb H$$_{2}$$O$$_{2}$$ at 453 K, however, IGSCC extended to the central region of the CT specimen. Effects of H$$_{2}$$O$$_{2}$$ on SCC growth behavior appeared stronger at lower temperature due to a reduction of the thermal decomposition of H$$_{2}$$O$$_{2}$$. Moreover, outer oxide layer of oxide film formed on the crack of the CT specimen was examined to estimate environmental situations in the cracks and a thermal equilibrium calculation was performed.

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