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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.
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.
mutants to microbeam irradiationSakashita, Tetsuya; Suzuki, Michiyo; Hattori, Yuya; Ikeda, Hiroko; Muto, Yasuko*; Yokota, Yuichiro; Funayama, Tomoo; Hamada, Nobuyuki*; Shirai, Kana*; Kobayashi, Yasuhiko
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 74, 2015/03
An increasing body of data indicates that ionizing radiation affects the nervous system and alters its function. Recently, we reported that chemotaxis of during the salt chemotaxis learning (SCL), that is conditioned taste aversion to NaCl, was modulated by carbon ion irradiation, i.e. accelerated decrease in chemotaxis to NaCl during the SCL. However, we had no direct evidence for the interaction of ionizing radiation with the central neuronal tissue (nerve ring) in . Microbeam irradiation is useful to analyze direct radiation effects at a cellular or tissue level. Thus, we applied the microbeam irradiation of the nerve ring and examined the effect on the SCL.
Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Mori, Michiaki; Orimo, Satoshi; Pirozhkov, A. S.; et al.
Physical Review Special Topics; Accelerators and Beams, 13(7), p.071304_1 - 071304_7, 2010/07
Times Cited Count：25 Percentile：79.43(Physics, Nuclear)A laser-driven repetition-rated 1.9 MeV proton beam line composed of permanent quadrupole magnets (PMQs), a radio frequency (rf) phase rotation cavity, and a tunable monochromator is developed to evaluate and to test the simulation of laser-accelerated proton beam transport through an integrated system for the first time. In addition, the proton spectral modulation and focusing behavior of the rf phase rotationcavity device is monitored with input from a PMQ triplet. In the 1.9 MeV region we observe very weakproton defocusing by the phase rotation cavity. The final transmitted bunch duration and transverse profile are well predicted by the PARMILA particle transport code. The transmitted proton beam duration of 6 ns corresponds to an energy spread near 5% for which the transport efficiency is simulated to be 10%. The predictive capability of PARMILA suggests that it can be useful in the design of future higher energy transport beam lines as part of an integrated laser-driven ion accelerator system.
Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Mori, Michiaki; Orimo, Satoshi; Pirozhkov, A. S.; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.88 - 90, 2010/05
The concept of a compact ion particle accelerator has become attractive in view of recent progress in laser-driven ion acceleration. We report here the recent progress in the laser-driven proton beam transport at the Photo Medical Research Center (PMRC) at JAEA, which is established to address the challenge of laser-driven ion accelerator development for ion beam cancer therapy.
Yogo, Akifumi; Daido, Hiroyuki; Mori, Michiaki; Kiriyama, Hiromitsu; Bulanov, S. V.; Bolton, P. R.; Esirkepov, T. Z.; Ogura, Koichi; Sagisaka, Akito; Orimo, Satoshi; et al.
Reza Kenkyu, 37(6), p.449 - 454, 2009/06
The acceleration of protons driven by a high-intensity laser is comprehensively investigated via control of the target density by using ASE just before the time of the main-laser interaction. Two cases were investigated for which the ASE intensity differed by three orders of magnitude: In the low contrast case the beam centre for higher energy protons is shifted closer to the laser-propagation direction of 45, while the center of lower-energy beam remains near the target normal direction. Particle-in-cell simulations reveal that the characteristic proton acceleration is due to the quasistatic magnetic field on the target rear side with the magnetic pressure sustaining a charge separation electrostatic field.
Mori, Michiaki; Yogo, Akifumi; Kiriyama, Hiromitsu; Nishiuchi, Mamiko; Ogura, Koichi; Orimo, Satoshi; Ma, J.*; Sagisaka, Akito; Kanazawa, Shuhei; Kondo, Shuji; et al.
IEEE Transactions on Plasma Science, 36(4), p.1872 - 1877, 2008/08
Times Cited Count：7 Percentile：28.47(Physics, Fluids & Plasmas)A dependence of cut-off proton kinetic energy on laser prepulse duration has been observed. ASE pedestal duration is controlled by a fast electro-optic pulse slicer where the risetime is estimated to be 130 ps. We demonstrate a new correlated spectral technique for determining this risetime using a stretched, frequency chirped pulse.
Orimo, Satoshi; Nishiuchi, Mamiko; Daido, Hiroyuki; Yogo, Akifumi; Ogura, Koichi; Sagisaka, Akito; Li, Z.*; Pirozhkov, A. S.; Mori, Michiaki; Kiriyama, Hiromitsu; et al.
Japanese Journal of Applied Physics, Part 1, 46(9A), p.5853 - 5858, 2007/09
Times Cited Count：17 Percentile：54.99(Physics, Applied)A laser-driven proton beam with a maximum energy of a few MeV is stably obtained using an ultra-short and high-intensity Titanium Sapphire laser. At the same time, keV X-ray is also generated at almost the same place where protons are emitted. Here, we show the successful demonstration of simultaneous proton and X-ray projection images of a test sample placed close to the source with a resolution of 
10
m, which is determined from the source sizes. Although the experimental configuration is very simple, the simultaneity is better than a few hundreds of ps. A CR-39 track detector and imaging plate, which are placed as close as possible to the CR-39, are used as detectors of protons and X-ray. The technique is applicable to the precise observation of microstructures.
Fukamoto, Kana; Shirai, Koji*; Sakata, Toshiyuki*; Sakashita, Tetsuya; Funayama, Tomoo; Hamada, Nobuyuki*; Wada, Seiichi*; Kakizaki, Takehiko; Shimura, Sachiko*; Kobayashi, Yasuhiko; et al.
Journal of Radiation Research, 48(3), p.247 - 253, 2007/05
Times Cited Count：17 Percentile：47.8(Biology)To carry out the radio-microsurgery study using silkworm, 
, we have already developed the specific irradiation systems for eggs and third to fifth instar larvae. In this study, a modified application consisting of the first instar silkworm larvae was further developed using heavy-ion microbeams. This system includes aluminum plates with holes specially designed to fix the first instar silkworm larvae during irradiation, and Mylar films were used to adjust energy deposited for planning radiation doses at certain depth. Using this system, the suppression of abnormal proliferation of epidermal cells in the knob mutant was examined. Following target irradiation of the knob-forming region at the first instar stage with 180-mum-diameter microbeam of 220 MeV carbon (
C) ions, larvae were reared to evaluate the effects of irradiation. The results indicated that the knob formation at the irradiated segment was specially suppressed in 5.9, 56.4, 66.7 and 73.6 % of larvae irradiated with 120, 250, 400 and 600 Gy, respectively, but the other knob formations at the non-irradiated segments were not suppressed in either irradiation. Although some larva did not survive undesired non-targeted exposure, our present results indicate that this method would be useful to investigate the irradiation effect on a long developmental period of time. Moreover, our system could also be applied to other species by targeting tissues, or organs during development and metamorphosis in insect and animals.
, after heavy-ion irradiation; Analysis by transplantation of the irradiated organs using a transgenic silkworm strainKiguchi, Kenji*; Shirai, Koji*; Sakata, Toshiyuki*; Fukamoto, Kana; Kakizaki, Takehiko; Wada, Seiichi*; Sakashita, Tetsuya; Funayama, Tomoo; Hamada, Nobuyuki*; Kobayashi, Yasuhiko
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 117, 2007/02
no abstracts in English
Daido, Hiroyuki; Sagisaka, Akito; Ogura, Koichi; Orimo, Satoshi; Nishiuchi, Mamiko; Mori, Michiaki; Ma, J.-L.; Pirozhkov, A. S.; Kiriyama, Hiromitsu; Kanazawa, Shuhei; et al.
Proceedings of 7th Pacific Rim Conference on Lasers and Electro-Optics (CLEO-PR 2007) (CD-ROM), p.77 - 79, 2007/00
We are developing a proton accelerator using an intense lasers with a focused intensity of 
10
W/cm
. To monitor proton energy spectra as well as plasma parameters at each laser shot, we are using real time detectors. The proton energy of MeV is stably obtained for applications.
cyst formation from the implanted larval integument in the sweet potato hornworm, 
; A Simple model for studying wound healingFukamoto, Kana; Shirai, Koji*; Sato, Shigeru*; Kanekatsu, Rensuke*; Kiguchi, Kenji*; Kobayashi, Yasuhiko
Journal of Insect Biotechnology and Sericology, 75(3), p.99 - 106, 2006/10
no abstracts in English
Fukamoto, Kana; Shimura, Sachiko*; Shirai, Koji*; Kanekatsu, Rensuke*; Kiguchi, Kenji*; Sakashita, Tetsuya; Funayama, Tomoo; Kobayashi, Yasuhiko
Journal of Insect Biotechnology and Sericology, 75(3), p.107 - 114, 2006/10
no abstracts in English
, after locally targeted irradiation with heavy ion beamsLing, E.*; Fukamoto, Kana*; Xu, S.*; Shirai, Koji*; Kanekatsu, Rensuke*; Kobayashi, Yasuhiko; Tu, Z.; Funayama, Tomoo; Watanabe, Hiroshi; Kiguchi, Kenji*
Journal of Insect Biotechnology and Sericology, 72(2), p.95 - 100, 2003/09
no abstracts in English
Sakata, Toshiyuki*; Shirai, Koji*; Kiguchi, Kenji*; Fukamoto, Kana; Kakizaki, Takehiko; Sakashita, Tetsuya; Funayama, Tomoo; Hamada, Nobuyuki*; Kobayashi, Yasuhiko
no journal, ,
no abstracts in English
Fukamoto, Kana; Sakata, Toshiyuki*; Shirai, Koji*; Sakashita, Tetsuya; Funayama, Tomoo; Wada, Seiichi*; Hamada, Nobuyuki*; Kakizaki, Takehiko; Hara, Takamitsu*; Suzuki, Michiyo*; et al.
no journal, ,
Silkworm is an experimental insect good to investigate developmental biology or cell differentiation. Knobbed mutant is a quite unique and important model of cell differentiation, in that cells in the knob region consist of abnormally proliferated and stratified cells. In this study, the new application of irradiation with heavy ion microbeam for the first instar silkworm larvae was developed to clarify that when and where the knob mutant would form abnormal proliferation of epidermal cells. The holed aluminum plates were designed to fix the first instar larvae of silkworm during irradiation. After carbon ions microbeam irradiation, larvae were reared to evaluate the accuracy of irradiation. The deletion of knob was observed in over 70% of the larvae at fifth instar. The epidermal cells stayed, as it was a monolayer at irradiated region. These results indicate that heavy ion beam irradiation can control the abnormal cell division of epidermis in the knob mutant.
Fukamoto, Kana; Sakata, Toshiyuki*; Shirai, Koji*; Sakashita, Tetsuya; Funayama, Tomoo; Wada, Seiichi*; Hamada, Nobuyuki*; Kakizaki, Takehiko; Hara, Takamitsu*; Suzuki, Michiyo; et al.
no journal, ,
no abstracts in English
Mori, Michiaki; Ogura, Koichi; Sagisaka, Akito; Orimo, Satoshi; Takai, Mamiko; Yogo, Akifumi; Kiriyama, Hiromitsu; Ma, J.-L.; Kanazawa, Shuhei; Kondo, Shuji; et al.
no journal, ,
no abstracts in English
Yogo, Akifumi; Daido, Hiroyuki; Mori, Michiaki; Sagisaka, Akito; Ogura, Koichi; Orimo, Satoshi; Kiriyama, Hiromitsu; Pirozhkov, A. S.; Kanazawa, Shuhei; Nakai, Yoshiki; et al.
no journal, ,
We report the result on a novel online analysis of fast ions generated in an ultraintense laser-foil interaction. Fast protons are observed by a time-of-flight (TOF) detector, which is precisely calibrated using proton beams from an ion accelerator as to its detection efficiency depending on the proton energy. The TOF detector provides shot-to-shot energy distributions of protons immediately after the irradiation of a high-intensity laser pulse of 10
W/cm
. Definite correlations are found between the prepulse intensity and the high energy cutoff of protons as well as the conversion efficiency of the laser energy into the proton energy, governing the stability of the repetitive proton generation.
Sakata, Toshiyuki*; Shirai, Koji*; Tsuchiya, Shiori*; Kiguchi, Kenji*; Fukamoto, Kana; Sakashita, Tetsuya; Kobayashi, Yasuhiko; Sato, Shigeru*
no journal, ,
no abstracts in English
