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Skobelev, I. Yu.*; Ryazantsev, S. N.*; Kulikov, R. K.*; Sedov, M. V.*; Filippov, E. D.*; Pikuz, S. A.*; Asai, Takafumi*; Kanasaki, Masato*; Yamauchi, Tomoya*; Jinno, Satoshi; et al.
Photonics (Internet), 10(11), p.1250_1 - 1250_11, 2023/11
Times Cited Count：0 Percentile：0.00(Optics)It is challenging to clearly distinguish the impacts of the optical field and collisional ionization in the evolution of the charge state of a plasma produced when matter interacts with high-intensity laser pulses. In this work, time-dependent calculations of plasma kinetics are used to show that it is possible only when low-density gaseous targets with sufficiently small clusters are used. In the case of Ar plasma, the upper limit of the cluster radius was estimated to be 
m.
Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.
Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12
Times Cited Count：6 Percentile：47.66(Geosciences, Multidisciplinary)The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.
Kubota, Tomohiro; Kuroda, Hisao*; Watanabe, Mirai*; Takahashi, Akiko*; Nakazato, Ryoji*; Tarui, Mika*; Matsumoto, Shunichi*; Nakagawa, Keita*; Numata, Yasuko*; Ouchi, Takao*; et al.
Atmospheric Environment, 243, p.117856_1 - 117856_9, 2020/12
Times Cited Count：3 Percentile：14.62(Environmental Sciences)The dry and wet depositions of atmospheric ammonia (NH
) is one of the important pathways of nitrogen loads to aquatic ecosystems. Crop and livestock agriculture, one of the largest emitters of NH in Asian countries, are known to cause high spatial and seasonal variation of NH and influence the surrounding lake basin areas via its dry and wet deposition. However, the spatial characteristics of the NH concentration in basin scale are not completely understood for regulation in NH emission. Here we aim to clarify dominant factors of spatial and seasonal variations of the NH concentration in a eutrophic lake basin surrounded by agricultural areas in Japan. Passive sampling over various land use categories in the basin was conducted at 36 sites in total from October 2018 to January 2020. Interestingly, the observed NH concentration near the livestock houses were higher in winter than summer, which was inconsistent with knowledge of seasonal changes of current NH emission inventory based on temperature-driven volatilization process. Comparing monthly NH concentrations with various meteorological factors, we suggested the importance of seasonal advection of NH from high emission sources to which has been rarely paid attention by the previous past studies. As for this, should be considered for lake ecosystem management since deposition of NH is known to be closely related to the ecological processes such as phytoplankton blooming.
ionsShiina, Yoko*; Kinoshita, Ryo*; Funada, Shuhei*; Matsuda, Makoto; Imai, Makoto*; Kawatsura, Kiyoshi*; Sataka, Masao*; Sasa, Kimikazu*; Tomita, Shigeo*
Nuclear Instruments and Methods in Physics Research B, 460, p.30 - 33, 2019/12
Times Cited Count：2 Percentile：22.69(Instruments & Instrumentation)Watanabe, Tamaki*; Toyama, Takeshi*; Hanamura, Kotoku*; Imao, Hiroshi*; Kamigaito, Osamu*; Kamoshida, Atsushi*; Kawachi, Toshihiko*; Koyama, Ryo*; Sakamoto, Naruhiko*; Fukunishi, Nobuhisa*; et al.
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1105 - 1108, 2019/07
Upgrades for the RIKEN heavy-ion linac (RILAC) involving a new superconducting linac (SRILAC) are currently underway at the RIKEN radioactive isotope beam factory (RIBF). It is crucially important to develop nondestructive beam measurement diagnostics. We have developed a beam energy position monitor (BEPM) system which can measure not only the beam position but also the beam energy simultaneously by measuring the time of flight of the beam. We fabricated 11 BEPMs and completed the position calibration to obtain the sensitivity and offset for each BEPMs. The position accuracy has been achieved to be less than 
0.1 mm by using the mapping measurement.
Hirota, Noriaki; Kasahara, Seiji; Iwatsuki, Jin; Imai, Yoshiyuki; Ohashi, Hirofumi; Yan, X.; Tachibana, Yukio
Zairyo To Kankyo, 68(6), p.137 - 142, 2019/06
New corrosion test equipment for high temperature gas of decomposed sulfuric acid was manufactured in order to ascertain flow rate of sulfuric acid in the piping, occurrence of sulfuric acid decomposition reaction in the equipment, and temperature distribution inside the furnace tube. The flow rate of the sulfuric acid solution was constantly measured using an ultrasonic flowmeter. The SO concentration at the inlet of the test equipment was almost the same as that at the inlet of the sulfuric acid decomposer in the hydrogen production plant assuming a high-temperature gas cooled reactor hydrogen-power cogeneration system (GTHTR300C). On the other hand, during a test, leakage of sulfuric acid occurred from the fitting part at the outlet side. Hence the temperature distribution of the fitting part at the outlet side was investigated using fluid analysis. As a result, it was found that the temperature at the fitting was low enough to use fluorine joint grease when the distance was 0.05 m or more away from the outlet side pipe. An improved furnace tube was manufactured and the temperature was measured again at fitting part of the outlet side. The temperature was lower that the temperature limit of the joint grease and almost the same as the temperature distribution in the fluid analysis, and leakage of sulfuric acid has not occurred to date.
Watanabe, Tamaki*; Imao, Hiroshi*; Kamigaito, Osamu*; Sakamoto, Naruhiko*; Fukunishi, Nobuhisa*; Fujimaki, Masaki*; Yamada, Kazunari*; Watanabe, Yutaka*; Koyama, Ryo*; Toyama, Takeshi*; et al.
Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.49 - 54, 2018/08
no abstracts in English
Sato, Satoshi*; Konno, Chikara; Nakashima, Hiroshi; Shionaga, Ryosuke*; Nose, Hiroyuki*; Ito, Yuji*; Hashimoto, Hirohide*
Journal of Nuclear Science and Technology, 55(4), p.410 - 417, 2018/04
Times Cited Count：1 Percentile：11.24(Nuclear Science & Technology)In order to enhance the neutron shielding performance, we developed concrete with boron of more than 10 wt%. We performed a neutron shielding experiment using the mockup of the newly developed boron-loaded concrete and DT neutrons at FNS in JAEA, and measured the reaction rates of the 
Nb(n,2n)
Nb and 
Au(n,
)
Au reactions in the mockup. The calculations were conducted by using MCNP-5.14 and FENDL-2.1. The calculation results agreed well with the measured ones, and we confirmed that the accuracy was very good on the atomic composition data of the boron-loaded concrete and their nuclear data. In addition, we calculated effective dose rates and reaction rates of the 
Co(n,)
Co and 
Eu(n,)
Eu reactions in the boron-loaded concrete and other concretes. It is concluded that the boron-loaded concrete has much better shielding performance for DT neutrons than other concretes.
Hirota, Noriaki; Iwatsuki, Jin; Imai, Yoshiyuki; Yan, X.
JAEA-Technology 2017-027, 19 Pages, 2017/12
JAEA-Technology-2017-027.pdf:2.08MB
In this study, austenitic Fe-based alloys and Ni based alloys was developed as candidate structural materials for equipment operated in sulfuric acid and hydrogen iodide (HI) environment, which exists in various industrial processes including iodine-sulfur (IS) hydrogen production process and geothermal power generation process. The objectives of the study are to achieve the corrosion resistance performance sufficient under the working condition of these processes and to overcome the practical scale-up difficulty of the ceramic (SiC) material that is presently used in the processes due to the manufacturing size limitation of the ceramic. The chemical composition development plan for the austenitic Fe-based alloys is threefold: reinforcement of matrix by addition of Cu and Ta, strength compensation of the surface film by addition of Si and Ti, and prevention of peeling of surface oxide by addition of rare earth elements. Because addition of Cu and Si is known to reduce the ductility of the material and thus manufacturability of the component, it is important to determine the allowable amount of each element to be added. On the other hand, the chemical composition development plan for the Ni based alloys is reinforcement of matrix by addition of Mo, W and Ta, strength compensation of the surface film by addition of Ti, and prevention of peeling of surface oxide by addition of rare earth elements. In particular, the addition of Mo and W to the Ni based alloy is expected to be effective in preventing dimensional deviation of structures from increasing during heating and cooling of process equipment. Various material specimens will be fabricated based on the above chemical composition development plans and tests on these specimens will then be carried out to confirm the corrosion resistance performance under the fluid conditions simulating each industrial processes.
Matsuoka, Moe*; Nakamura, Tomoki*; Osawa, Takahito; Iwata, Takahiro*; Kitazato, Kohei*; Abe, Masanao*; Nakauchi, Yusuke*; Arai, Takehiko*; Komatsu, Mutsumi*; Hiroi, Takahiro*; et al.
Earth, Planets and Space (Internet), 69(1), p.120_1 - 120_12, 2017/12
Times Cited Count：6 Percentile：21.36(Geosciences, Multidisciplinary)We have conducted ground-based performance evaluation tests of the Near-Infrared Spectrometer (NIRS3) onboard Hayabusa2 spacecraft and established a method for evaluating its measured reflectance spectra. Reflectance spectra of nine powdered carbonaceous chondrite samples were measured by both NIRS3 and a FT-IR spectrometer. Since raw data obtained by NIRS3 had considerable spectral distortion caused by systematic offsets in sensitivity of individual pixels, we have established two methods for correcting the NIRS3 data by comparing them with the corresponding FT-IR data. In order to characterize the absorption bands in NIRS3 spectra, the depth of each band component D
is defined for each wavelength (
m). Reflectance spectra of asteroid Ryugu, the target asteroid of Hayabusa2, to be recorded by the NIRS3 are expected to reveal the characteristics of the surface materials by using the evaluation technique.
Kon, Akira; Nishiuchi, Mamiko; Kiriyama, Hiromitsu; Ogura, Koichi; Mori, Michiaki; Sakaki, Hironao; Kando, Masaki; Kondo, Kiminori
Journal of Physics; Conference Series, 717, p.012103_1 - 012103_4, 2016/05
Times Cited Count：2 Percentile：66.62(Physics, Applied)Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03
The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.
Yamaguchi, Hiroshi*; Ijichi, Ryo*; Suzuki, Yoshiyuki*; Ooka, Sachiyo*; Shimada, Keiji*; Takahashi, Naoki*; Washio, Hidetoshi*; Nakamura, Kazuyo*; Takamoto, Tatsuya*; Imaizumi, Mitsuru*; et al.
Proceedings of 42nd IEEE Photovoltaic Specialists Conference (PVSC-42) (CD-ROM), p.2407 - 2411, 2015/06
Fe polarization dependent synchrotron M
ssbauer spectroscopy using a diamond phase plate and an iron borate nuclear Bragg monochromatorMitsui, Takaya; Imai, Yasuhiko*; Masuda, Ryo*; Seto, Makoto*; Mibu, Ko*
Journal of Synchrotron Radiation, 22(2), p.427 - 435, 2015/03
Times Cited Count：11 Percentile：52.37(Instruments & Instrumentation)Kiriyama, Hiromitsu; Mori, Michiaki; Pirozhkov, A. S.; Ogura, Koichi; Sagisaka, Akito; Kon, Akira; Esirkepov, T. Z.; Hayashi, Yukio; Kotaki, Hideyuki; Kanasaki, Masato*; et al.
IEEE Journal of Selected Topics in Quantum Electronics, 21(1), p.1601118_1 - 1601118_18, 2015/01
Times Cited Count：61 Percentile：95.30(Engineering, Electrical & Electronic)This paper reviews the development of a high-contrast high-intensity petawatt-class Ti:sapphire chirped-pulse amplification (CPA) laser for research on high field science. We discuss in detail the design, performance and characterization of the laser. We also describe the on-going upgrade of the laser system and some applications for the laser in relativistic dominated laser-matter interactions.
-edge jump and shift on white-line of Pd interlayer for trilaminar neutron production target under H irradiationIshiyama, Shintaro; Fujii, Ryo*; Nakamura, Masaru*; Imahori, Yoshio*
Journal of Chemistry and Chemical Engineering, 8(9), p.870 - 875, 2014/09
Interlayer Pd for the Li/Pd/Cu neutron target for BNCT (Boron Neutron Capture Therapy) was characterized after 0.1-5 keV H irradiation by XAFS technique, and following conclusions were derived; (1) From the XAFS observation of white line of Pd, remarkable Pd Edge jump was found in 1.1-3 times higher than before irradiation in low irradiation fluence. (2) This fact indicates increase of hole density in Pd 4d-band, whereas no change was observed for XASF spectra of Ag sample under the same irradiation conditions. (3) Remarkable Pd Edge shift of 0.12-0.66 eV was also found with increase of H irradiation energy in low fluence, and drastically decreased after peak in high irradiation energy and fluence.(4)Implanted protons deposited in Pd as negative under the balance of electron population enhanced by proton irradiation and charge transfer.
O addition on lithium target for BNCTIshiyama, Shintaro; Baba, Yuji; Fujii, Ryo*; Nakamura, Masaru*; Imahori, Yoshio*
Nihon Kinzoku Gakkai-Shi, 78(8), p.317 - 321, 2014/08
Times Cited Count：0 Percentile：0.01(Metallurgy & Metallurgical Engineering)Low temperature synthesis of lithium-nitride compound was conducted on the lithium target for BNCT by N/HO mixing gas squirt in the ultra high vacuum chamber, and the following results were derived; (1) Lithium-nitride compound was synthesized on the lithium target under 101.3 Pa N gas squirt at room temperature and in the ultra high vacuum chamber under the pressure of 110
Pa. (2) Remarkable contamination by O and C was observed on the lithium-nitride compound synthesized under the squirt pressure of 13.3-80 Pa/1.33-4.7 Pa N/HO mixing gas. (3) No contamination and synthesis of Li-N compound was observed under the squirt pressure of 0.013-0.027 Pa/0-0.005 Pa N/HO mixing gas. (4) Contamination by O and C was enhanced with excessive addition of HO at the pressure of over 1.33 Pa.
N synthesized on lithium target for boron neutron capture therapyIshiyama, Shintaro; Baba, Yuji; Fujii, Ryo*; Nakamura, Masaru*; Imahori, Yoshio*
Nihon Kinzoku Gakkai-Shi, 78(8), p.322 - 325, 2014/08
Times Cited Count：0 Percentile：0.01(Metallurgy & Metallurgical Engineering)To remove high level of contaminants by O and C from LiN surface for boron neutron capture therapy target, high temperature thermal desorption was conducted up to 1123 K in ultra high vacuum and the following results were derived; (1) During thermal desorption up to 1023 K, typical three peaks of vacuum pressure disturbance due to vaporization of contaminants were observed in vacuum pressure-temperature curve. (2) Over-layered contaminants with high melting temperature below 1023 K on LiN surface is completely removed by high temperature thermal desorption up to 1123 K in ultra high vacuum. (3) From these desorption results, it is suggested that these contaminants corresponding to these vaporization peaks are HO and Li compounds with high melting temperature below 1023 K, of which LiOH and LiCO were synthesized by decomposition process of LiN with residual HO and CO in low temperature.
Sr
NiO
Kajimoto, Ryoichi; Fujita, Masaki*; Nakajima, Kenji; Ikeuchi, Kazuhiko*; Inamura, Yasuhiro; Nakamura, Mitsutaka; Imasato, Takuro*
Journal of Physics; Conference Series, 502(1), p.012056_1 - 012056_5, 2014/04
Times Cited Count：1 Percentile：53.38(Materials Science, Multidisciplinary)N thin layer on lithium target surface for BNCT in N gaseous conditionsIshiyama, Shintaro; Baba, Yuji; Fujii, Ryo*; Nakamura, Masaru*; Imahori, Yoshio*
Nihon Kinzoku Gakkai-Shi, 78(4), p.137 - 141, 2014/04
Times Cited Count：0 Percentile：0.01(Metallurgy & Metallurgical Engineering)To prevent vaporization damage of BNCT (Boron Neutron Capture Therapy) lithium target during operation, direct synthesis of LiN thin layer on lithium target surface was demonstrated in 0.1 MPa N gas at temperature below 548 K and the following conclusions were derived; (1) Synthesis of LiN thin layer on lithium surface was confirmed after nitridation at 276
548 K with surface contamination by oxygen and carbon. (2) Rapid nitridation over 1-5wt.%/min was observed above Li melting temperature, whereas slow reaction under 0.02-0.5 wt.%/min below melting temperature. (3) During nitridation, removal of oxygen contamination on LiN thin layer is taken place by nitrogen below Li melting temperature.
