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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：44 Percentile：96.99(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.
Finsterle, S.*; Lanyon, B.*; 
kesson, M.*; Baxter, S.*; Bergstr
m, M.*; Bockg
rd, N.*; Dershowitz, W.*; Dessirier, B.*; Frampton, A.*; Fransson, .*; et al.
Geological Society, London, Special Publications, No.482, p.261 - 283, 2019/00
Times Cited Count：9 Percentile：69.73(Geology)Nuclear waste disposal in geological formations relies on a multi-barrier concept that includes engineered components which in many cases includes a bentonite buffer surrounding waste packages and the host rock. An SKB's (Swedish Nuclear Fuel and Waste Management Co.) Modelling Task Force project facilitated to improve the overall understanding of rock - bentonite interactions, as 11 teams used different conceptualisations and modelling tools to analyse the in-situ experiment at the 
ps Hard Rock Laboratory. The exercise helped identify conceptual uncertainties that led to different assessments of the relative importance of the engineered and natural barrier subsystems and of aspects that need to be better understood to arrive at reliable predictions of bentonite wetting.
Sawada, Atsushi; Saegusa, Hiromitsu; Takeuchi, Shinji*; Sakamoto, Kazuhiko*; Dershowitz, W. S.*
SKB P-13-46, 82 Pages, 2015/12
Nakajima, Makoto*; Seno, Shoji*; Onoe, Hironori; Ishibashi, Masayuki; Saegusa, Hiromitsu; Sawada, Atsushi
Dai-42-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.107 - 112, 2014/01
Japan Atomic Energy Agency is proceeding with the Mizunami Underground Research Laboratory Project in order to establish comprehensive techniques for the investigation, analysis and assessment of the deep geological environment in fractured crystalline rock for geological disposal of high level radioactive wastes. We have carried out discrete fracture network modeling, groundwater flow and particle tracking simulation in order to understand the important factors for the solute transport characterizations. In this paper, a method for estimating hydraulic parameter of discrete fracture network model based on in-situ data at underground gallery are described.
irradiated with swift heavy ionsYasuda, Kazuhiro*; Eto, Motoki*; Sawada, Kenichi*; Yamamoto, Tomokazu*; Yasunaga, Kazufumi*; Matsumura, Sho*; Ishikawa, Norito
Nuclear Instruments and Methods in Physics Research B, 314, p.185 - 190, 2013/11
Times Cited Count：34 Percentile：92.41(Instruments & Instrumentation)We have investigated microstructure evolution in CeO irradiated with 210 MeV Xe ions by using transmission electron microscopy to gain the fundamental knowledge on radiation damage induced by fission fragments in nuclear fuel and transmutation target.
Tokiwa, Tetsuya; Sawada, Sumiyuki; Ochiai, Shoji; Miyakawa, Kazuya
Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.1021 - 1025, 2013/01
In the Horonobe area of Japan, underground facilities have been excavated in soft sedimentary rocks in order to enhance the reliability of relevant technologies for geological disposal of high-level radioactive waste in Japan. Pre-excavation grouting was carried out at 250 to 380 m depth at the location of the planned Ventilation Shaft. After the grouting, the shaft was excavated from 250 to 350 m depth, and fracture mapping was carried out to understand the characteristics of water conductive fractures by focusing on the occurrence of injected grout. Fractures consist mainly of shear fractures, and extension fractures and faults are observed in the shaft. The faults are associated with fault rocks and high continuity. Grout was mainly observed in fractures located on the branching part from faults rather than the fault itself, and therefore high-permeability fractures are not the fault itself (fault core) but fractures located on the branching part in the damage zone of the fault.
Sawada, Yusuke*; Uozumi, Yusuke*; Nogamine, Sho*; Yamada, Takehiro*; Iwamoto, Yosuke; Sato, Tatsuhiko; Niita, Koji*
Nuclear Instruments and Methods in Physics Research B, 291, p.38 - 44, 2012/11
Times Cited Count：17 Percentile：76.66(Instruments & Instrumentation)The Intranuclear cascade with emission of light fragment (INC-ELF) code has been developed and implemented in the particle and heavy ion transport code system (PHITS). The INC-ELF code explicitly includes nucleon correlations within the framework of the INC model to describe light fragment emissions from nuclear spallation reactions. In addition to the degrees of freedom of nucleons, the developed code also accounts for pions, 
and 
, and it can cover the energy range up to 3 GeV. The predictive capabilities of the ELF/PHITS system have been verified through comparison with a diverse set of experimental observations. As a result, our ELF/PHITS code has demonstrated strong predictive capability for all of these data, although areas requiring future study remain due to the lack of experimental data on high-energy cluster production.
Chikazawa, Yoshitaka; Kotake, Shoji; Sawada, Shusaku*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR 2009) (CD-ROM), 12 Pages, 2012/00
Uozumi, Yusuke*; Sawada, Yusuke*; Mzhavia, A.*; Nogamine, Sho*; Iwamoto, Hiroki; Kin, Tadahiro; Hohara, Shinya*; Wakabayashi, Genichiro*; Nakano, Masahiro*
Physical Review C, 84(6), p.064617_1 - 064617_11, 2011/12
Times Cited Count：18 Percentile：72.08(Physics, Nuclear)Deuteron production from intermediate-energy proton-nucleus interactions was investigated through experiments and model calculations, mainly to develop a theoretical model by elucidating the mechanism of cluster production. Spectral double-differential cross sections were measured for inclusive (
, 
) reactions on five targets in the periodic table, namely 
C, 
Al, 
V, 
Nb, and 
Au, at beam energies of 300 and 392 MeV. The cross sections were determined in almost the entire outgoing energy range from the highest down to 30 MeV and at laboratory angles from 20 to 104. To interpret the measured spectra, we proposed a new model that includes the nucleon correlations of the initial- and final-state interactions to describe cluster knockout and pickup within the intranuclear cascade model. The results of the model calculations showed reasonable agreements with those of the experiments. Moreover, the model indicated reasonable predictive power for the (, 
He
), (, 
), and (
, ) reactions measured elsewhere.
collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review D, 84(1), p.012006_1 - 012006_18, 2011/07
Times Cited Count：29 Percentile：73.1(Astronomy & Astrophysics)We report on the event structure and double helicity asymmetry (
) of jet production in longitudinally polarized collisions at = 200 GeV. Photons and charged particles were measured by the PHENIX experiment. Event structure was compared with the results from PYTHIA event generator. The production rate of reconstructed jets is satisfactorily reproduced with the next-to-leading-order perturbative QCD calculation. We measured = -0.0014 
0.0037 at the lowest 
bin and -0.0181 0.0282 at the highest bin. The measured is compared with the predictions that assume various 
distributions.
collisions at = 200 and 62.4 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count：184 Percentile：99.42(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
and Au+Au collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
Times Cited Count：9 Percentile：52.86(Physics, Nuclear)Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.
+ collisions at = 200 GeV and scaling properties of hadron productionAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review D, 83(5), p.052004_1 - 052004_26, 2011/03
Times Cited Count：177 Percentile：98.48(Astronomy & Astrophysics)The PHENIX experiment at RHIC has measured the invariant differential cross section for production of 
, 
, 
and 
mesons in collisions at = 200 GeV. The spectral shapes of all hadron transverse momentum distributions are well described by a Tsallis distribution functional form with only two parameters, 
and 
, determining the high 
and characterizing the low regions for the spectra, respectively. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.
Chikazawa, Yoshitaka; Kotake, Shoji; Sawada, Shusaku*
Nuclear Engineering and Design, 241(1), p.378 - 385, 2011/01
Times Cited Count：4 Percentile：32.36(Nuclear Science & Technology)Osawa, Hideaki; Sawada, Atsushi; Umeki, Hiroyuki; Hama, Katsuhiro; Takase, Hiroyasu*; Tachibana, Shoko*
no journal, ,
This presentation shows basic design of Information Synthesis and Interpretation System based on the traial of making some expert systems.
Atsumi, Hiroyuki*; Nakajima, Makoto*; Seno, Shoji*; Masumoto, Kazuhiko*; Kawabata, Junichi*; Onoe, Hironori; Kunimaru, Takanori; Sawada, Atsushi; Saegusa, Hiromitsu; Watanabe, Kunio*
no journal, ,
Solute transport conceptual models for crystalline rock environment is developed in the Mizunami Underground Research Laboratory (MIU) project conducted by Japan Atomic Energy Agency (JAEA) in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). In this study, groundwater flow analysis and solute transport analysis are conducted to analyze factors in the solute transport behavior using hydro-geological model composed of channel network.
Masumoto, Kazuhiko*; Atsumi, Hiroyuki*; Iwano, Keita*; Nakajima, Makoto*; Seno, Shoji*; Kawabata, Junichi*; Saegusa, Hiromitsu; Onoe, Hironori; Sawada, Atsushi
no journal, ,
no abstracts in English
Iwano, Keita*; Atsumi, Hiroyuki*; Nakajima, Makoto*; Masumoto, Kazuhiko*; Seno, Shoji*; Kawabata, Junichi*; Onoe, Hironori; Saegusa, Hiromitsu; Sawada, Atsushi
no journal, ,
no abstracts in English
Sawada, Sho; Maki, Shota; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke; Osawa, Takayasu
no journal, ,
no abstracts in English
Sawada, Sho
no journal, ,
no abstracts in English
