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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：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.
Toyokawa, Hidenori*; Saji, Choji*; Kawase, Morihiro*; Wu, S.*; Hurukawa, Yukihito*; Kajiwara, Kentaro*; Sato, Masugu*; Hirono, Toko*; Shiro, Ayumi*; Shobu, Takahisa; et al.
Journal of Instrumentation (Internet), 12(1), p.C01044_1 - C01044_7, 2017/01
Times Cited Count：4 Percentile：21.22(Instruments & Instrumentation)We have been developing CdTe pixel detectors combined with a Schottky diode sensor and photon-counting ASICs. The hybrid pixel detector was designed with a pixel size of 200 micro-meter by 200 micro-meter and an area of 19 mm by 20 mm or 38.2 mm by 40.2 mm. The photon-counting ASIC, SP8-04F10K, has a preamplifier, a shaper, 3-level window-type discriminators and a 24-bits counter in each pixel. The single-chip detector with 100 by 95 pixels successfully operated with a photon-counting mode selecting X-ray energy with the window comparator and stable operation was realized at 20C. We have performed a feasibility study for a white X-ray microbeam experiment. Laue diffraction patterns were measured during the scan of the irradiated position in a silicon steel sample. The grain boundaries were identified by using the differentials between adjacent images at each position.
Motokawa, Ryuhei; Kobayashi, Toru; Endo, Hitoshi*; Ikeda, Takashi; Yaita, Tsuyoshi; Suzuki, Shinichi; Narita, Hirokazu*; Akutsu, Kazuhiro*; Heller, W. T.*
Journal of Nuclear Science and Technology, 53(8), p.1205 - 1211, 2016/08
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Makino, Takahiro; Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi; Kobayashi, Daisuke*; Ikeda, Hirokazu*; Hirose, Kazuyuki*
Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.169 - 172, 2010/10
Digital Single Event Transient (DSET) pulse-widths in an inverter cell fabricated with the 0.2 mm FD-SOI process were estimated from high-energy heavy-ion-induced transient current in a single n-type MOSFET fabricated with the 0.2 mm FD-SOI process. We verified that the estimation method is applicable to the DSET pulse-widths estimation in the case of high-energy heavy-ion irradiation.
Makino, Takahiro*; Kobayashi, Daisuke*; Hirose, Kazuyuki*; Yanagawa, Yoshimitsu*; Saito, Hirobumi*; Ikeda, Hirokazu*; Takahashi, Daisuke*; Ishii, Shigeru*; Kusano, Masaki*; Onoda, Shinobu; et al.
IEEE Transactions on Nuclear Science, 56(1), p.202 - 207, 2009/02
Times Cited Count：36 Percentile：90.64(Engineering, Electrical & Electronic)SET pulse-widths were measured as a function of LET by using pulse capture circuits and were simulated with mixed-mode 3-D device simulations. We found that the carrier recombination process dominates LET dependence of SET pulse-widths.
Makino, Takahiro*; Yanagawa, Yoshimitsu*; Kobayashi, Daisuke*; Fukuda, Seisuke*; Hirose, Kazuyuki*; Ikeda, Hirokazu*; Saito, Hirobumi*; Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi; et al.
Shingaku Giho, 108(100), p.67 - 72, 2008/06
SET pulse-widths were measured as a function of LET by using pulse capture circuits. In addition, a scan flip-flop (FF) is designed to observe both single event transient (SET) and single event upset (SEU) soft errors in logic VLSI system.
Koshizuka, Seiichi*; Ikeda, Hirokazu*; Liu, J.*; Oka, Yoshiaki*
JAERI-Tech 2002-013, 60 Pages, 2002/03
JAERI-Tech-2002-013.pdf:3.16MB
no abstracts in English
Haga, Yoshinori; Inada, Yoshihiko*; Harima, Hisatomo*; Oikawa, Kenichi*; Murakawa, Masao*; Nakawaki, Hirokazu*; Tokiwa, Yoshifumi; Aoki, Dai*; Shishido, Hiroaki*; Ikeda, Shugo*; et al.
Physical Review B, 63(6), p.060503_1 - 060503_4, 2001/02
Times Cited Count：145 Percentile：97.42(Materials Science, Multidisciplinary)We observed the de Haas-van Alphen oscillation in the heavy fermion compound CeIrIn5. The topology of the Fermi surface is found to be neary cylindrical, reflecting the unique tetragonal structure. Observed branches are well explained by the 4f-itinerant band model. The cyclotron masses are large, 20-30 m0, which are one order larger than the corresponding band masses.
Makino, Takahiro*; Kobayashi, Daisuke*; Hirose, Kazuyuki*; Yanagawa, Yoshimitsu*; Saito, Hirobumi*; Ikeda, Hirokazu*; Takahashi, Daisuke*; Ishii, Shigeru*; Kusano, Masaki*; Onoda, Shinobu; et al.
no journal, ,
no abstracts in English
Akutsu, Kazuhiro; Shiwaku, Hideaki; Okamoto, Yoshihiro; Suzuki, Shinichi; Ikeda, Atsushi; Kobayashi, Toru*; Numakura, Masahiko; Mahara, Saori*; Nakano, Yoshiharu*; Fujii, Yuki*; et al.
no journal, ,
no abstracts in English
Makino, Takahiro; Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi; Kobayashi, Daisuke*; Ikeda, Hirokazu*; Hirose, Kazuyuki*
no journal, ,
no abstracts in English
Makino, Takahiro; Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi; Kobayashi, Daisuke*; Ikeda, Hirokazu*; Hirose, Kazuyuki*
no journal, ,
no abstracts in English
