Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：43 Percentile：96.93(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.
Science, 364(6437), p.272 - 275, 2019/04
Times Cited Count：259 Percentile：99.73(Multidisciplinary Sciences)The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.
Obata, Takashi; Numata, Kazuyoshi; Namiki, Shinji; Suzuki, Tsuneo*; Yamauchi, Takahiro*
Dai-24-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu, p.65 - 70, 2003/00
For the nuclear material accounting system, the mainframe computer had been used in Japan Atomic Energy Research Institute (JAERI). For the purpose of more flexible use and easy operation, the PC base accounting system has been developed since 1999, and operation started from October, 2002. This system consists of the server with the database software and the client PC with original application software. The functions of this system are the input and edit of data, the creation of inspection correspondence data, and creation of a report to the states. Furthermore, it is also possible to create the Web application which used accounting data on a user level by using the programming language. Now, this system is being specialized in JAERI, but it is during a plan to develop as a system which can be also used at other institutions and organization. In the paper, the outline and operating situation of the nuclear material accounting system of JAERI are presented.
Baba, Shinichi; Ishihara, Masahiro; Suzuki, Yoshio*; Takahashi, Tsuneo*; Hoshiya, Taiji
JAERI-Data/Code 2002-008, 126 Pages, 2002/03
JAERI-Data-Code-2002-008.pdf:4.82MB
no abstracts in English
Baba, Shinichi; Suzuki, Yoshio*; Takahashi, Tsuneo*; Ishihara, Masahiro; Hayashi, Kimio; Saito, Tamotsu; Sozawa, Shizuo; Saito, Takashi; Sekino, Hajime
JAERI-Research 2001-028, 109 Pages, 2001/03
JAERI-Research-2001-028.pdf:4.55MB
no abstracts in English
Soyama, Kazuhiko; Suzuki, Masatoshi; Kodaira, Tsuneo; Ebisawa, Toru*; *; Tasaki, Seiji*
Physica B; Condensed Matter, 213-214, p.951 - 953, 1995/00
Times Cited Count：2 Percentile：18.64(Physics, Condensed Matter)no abstracts in English
Uehara, Kazuya; Ikeda, Yoshitaka; Saigusa, Mikio; Sakamoto, Keishi; Fujii, Tsuneyuki; Maebara, Sunao; Tsuneoka, Masaki; Seki, Masami; Moriyama, Shinichi; Kobayashi, Noriyuki*; et al.
Fusion Engineering and Design, 19(1), p.29 - 40, 1992/07
Times Cited Count：1 Percentile：17.26(Nuclear Science & Technology)no abstracts in English
Nishiyama, Yutaka; Fukaya, Kiyoshi; Suzuki, Masahide; Kodaira, Tsuneo; Oku, Tatsuo*
Effects of Radiation on Materials; 15th International Symposium (ASTM STP 1125), p.1287 - 1303, 1992/00
no abstracts in English
Suzuki, Masahide; Eto, Motokuni; Fukaya, Kiyoshi; Nishiyama, Yutaka; Kodaira, Tsuneo; Oku, Tatsuo; ; ; ; *; et al.
Journal of Nuclear Materials, 179-181, p.441 - 444, 1991/00
Times Cited Count：29 Percentile：92.44(Materials Science, Multidisciplinary)no abstracts in English
Oku, Tatsuo; Kodaira, Tsuneo; Fukaya, Kiyoshi; Suzuki, Masahide; *; *; *; *
Nucl. Eng. Des., 119, p.177 - 186, 1990/00
Times Cited Count：5 Percentile：52.84(Nuclear Science & Technology)no abstracts in English
*; *; *; *; *; *; Oku, Tatsuo; Kodaira, Tsuneo; Fukaya, Kiyoshi; Nishi, Hiroshi; et al.
JAERI-M 88-172, 20 Pages, 1988/09
no abstracts in English
Ikeda, Yoshitaka; Imai, Tsuyoshi; Sakamoto, Keishi; Honda, Masao; *; Maebara, Sunao; Sawahata, Masayuki; Suganuma, Kazuaki; Suzuki, Norio; Tsuneoka, Masaki; et al.
AIP Conference Proceedings 159, p.119 - 122, 1987/00
no abstracts in English
for production of 
Tc by neutron irradiationSuematsu, Hisayuki*; Sato, Soma*; Nanko, Makoto*; Tsuchiya, Kunihiko; Nishikata, Kaori; Suzuki, Tsuneo*; Nakayama, Tadachika*; Niihara, Koichi*
no journal, ,
Spark plasma sintering of MoO was carried out for production of Tc from 
Mo by the (n,
) method in a nuclear reactor. Powder of MoO with an average grain size of 0.8
m and a purity of 99.99% was pressed in a graphite die with a diameter of 20 mm. Then, the green compact was heated in a spark plasma sintering apparatus with heating rates of 100 
200C/min to 500 600C in vacuum. After holding the temperature for 5 min, the sample was quenched. The sintered samples were characterized by powder X-ray diffraction for phase identifications, electron energy loss spectroscopy for compositional analyses and scanning electron microscopy for grain size measurements. After sintering at 550C, a sintered bulk of MoO with a relative density of 98% was obtained. These properties are good enough for separation of Tc and recycle of Mo.
powder for a radioisotope productionSato, Soma*; Nanko, Makoto*; Suzuki, Tsuneo*; Nakayama, Tadachika*; Suematsu, Hisayuki*; Niihara, Koichi*; Tsuchiya, Kunihiko
no journal, ,
no abstracts in English
for production of radioactive isotopesSuematsu, Hisayuki*; Seki, Misaki*; Sato, Soma*; Nanko, Makoto*; Tsuchiya, Kunihiko; Nishikata, Kaori; Suzuki, Tsuneo*; Nakayama, Tadachika*; Niihara, Koichi*
no journal, ,
no abstracts in English
for Production of Radioactive IsotopesSuematsu, Hisayuki*; Sato, Soma*; Seki, Misaki*; Nanko, Makoto*; Nishikata, Kaori; Suzuki, Yoshitaka; Tsuchiya, Kunihiko; Suzuki, Tsuneo*; Nakayama, Tadachika*; Niihara, Koichi*
no journal, ,
Tc has been utilized as a radioactive isotope in medical applications. The majority of this isotope has been separated from nuclear fission products in testing reactors with highly enriched 
U fuel. However, these reactors have been shut down because of the age and the nuclear security reasons. On the other hand, a nuclear reaction method has been proposed. This method is to irradiate Mo by neutrons in a reactor to form Mo and then to decay to Tc. As the target, MoO pellets are required. However, because of the low evaporation temperature (700 C) and coarse grain size of Mo enriched powder, it was difficult to obtain high density MoO pellets. To overcome this problem, a two-step loading method in pulsed electric current sintering was carried out in this study.
Mo/Tc generator for medicalSeki, Misaki*; Suematsu, Hisayuki*; Nakayama, Tadachika*; Suzuki, Tsuneo*; Niihara, Koichi*; Suzuki, Tatsuya*; Tsuchiya, Kunihiko; Duong Van, D.*
no journal, ,
no abstracts in English
Ogawa, Toru; Utsumi, Taro*; Terasawa, Toshiharu*; Kudo, Isamu*; Suzuki, Tsuneo*; Nakayama, Tadachika*; Suematsu, Hisayuki*
no journal, ,
For the fuel debris management, we develop the preparation techniques for highly porous geopolymer, which would be used as the matrix of neutron absorber as well as hydrogen recombiner. By adding silicon powder to the raw materials, and hot water in mixing, we demonstrated the capability to prepare geopolymer with high fractions of open pores.
Takir, D.*; Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; et al.
no journal, ,
JAXA spacecraft and sample return mission Hayabusa2 has arrived at the near-Earth asteroid 162173 Ryugu, which is classified a primitive carbonaceous object. Here we report recent results of near-infrared spectrometer (NIRS3) on the Hayabusa2 spacecraft. The observations provide direct measurements of the surface composition of Ryugu and context for the returned samples. NIRS3 has detected a weak and narrow absorption feature centered at 2.72 micrometer across entire observed surface. This absorption feature is attributed to the presence of OH-bearing minerals. The NIRS3 observations also revealed that Ryugu is the darkest object to be observed up-close by a visiting spacecraft. The intensity of the OH feature and low albedo are consistent with thermally-and/or shock-metamorphosed, and/or carbon-rich space-weathered primitive and hydrated carbonaceous chondrites.
