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Osawa, Takahito; Nagasawa, Shunsaku*; Ninomiya, Kazuhiko*; Takahashi, Tadayuki*; Nakamura, Tomoki*; Wada, Taiga*; Taniguchi, Akihiro*; Umegaki, Izumi*; Kubo, Kenya*; Terada, Kentaro*; et al.
ACS Earth and Space Chemistry (Internet), 7(4), p.699 - 711, 2023/04
Times Cited Count：4 Percentile：92.07(Chemistry, Multidisciplinary)The concentrations of carbon and other major elements in asteroid samples provide very important information on the birth of life on the Earth and the solar-system evolution. Elemental analysis using muonic X-rays is one of the best analytical methods to determine the elemental composition of solid materials, and notably, is the only method to determine the concentration of light elements in bulk samples in a non-destructive manner. We developed a new analysis system using muonic X-rays to measure the concentrations of carbon and other major elements in precious and expectedly tiny samples recovered from the asteroid Ryugu by spacecraft Hayabusa2. Here we report the development process of the system in 4 stages and their system configurations, The analysis system is composed of a stainless-steel analysis chamber, an acrylic glove box for manipulating asteroid samples in a clean environment, and Ge semiconductor detectors arranged to surround the analysis chamber. The performance of the analysis system, including the background level, which is crucial for the measurement, was greatly improved from the first stage to the later ones. Our feasibility study showed that the latest model of our muonic X-ray analysis system is capable of determining the carbon concentration in Hayabusa2's sample model with an uncertainty of less than 10 percent in a 6-day measurement.
Zheng, X.*; Kato, Masaru*; Uemura, Yohei*; Matsumura, Daiju; Yagi, Ichizo*; Takahashi, Kiyonori*; Noro, Shinichiro*; Nakamura, Takayoshi*
Inorganic Chemistry, 62(3), p.1257 - 1263, 2023/01
Times Cited Count：1 Percentile：52.7(Chemistry, Inorganic & Nuclear)Endo, Shunsuke; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki; Rovira Leveroni, G.; Terada, Kazushi*; Meigo, Shinichiro; Toh, Yosuke; Segawa, Mariko; et al.
Journal of Nuclear Science and Technology, 59(3), p.318 - 333, 2022/03
Times Cited Count：6 Percentile：64.12(Nuclear Science & Technology)
SGo, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Aoi, Nori*; Azaiez, F.*; Furutaka, Kazuyoshi; Hatsukawa, Yuichi; Kimura, Atsushi; Kisamori, Keiichi*; Kobayashi, Motoki*; et al.
Physical Review C, 103(3), p.034327_1 - 034327_8, 2021/03
Times Cited Count：4 Percentile：55.56(Physics, Nuclear)
scattering length from 
photoproduction on the proton near the reaction thresholdIshikawa, Takatsugu*; Fujimura, Hisako*; Fukasawa, Hiroshi*; Hashimoto, Ryo*; He, Q.*; Honda, Yuki*; Hosaka, Atsushi; Iwata, Takahiro*; Kaida, Shun*; Kasagi, Jirota*; et al.
Physical Review C, 101(5), p.052201_1 - 052201_6, 2020/05
Times Cited Count：4 Percentile：44.35(Physics, Nuclear)Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.
Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07
Times Cited Count：8 Percentile：55.71(Physics, Multidisciplinary)Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for 
Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.
Hidaka, Akihide; Nakano, Yoshihiro; Watanabe, Yoko; Arai, Nobuyoshi; Sawada, Makoto; Kanaizuka, Seiichi*; Katogi, Aki; Shimada, Mayuka*; Ishikawa, Tomomi*; Ebine, Masako*; et al.
JAEA-Review 2016-011, 208 Pages, 2016/07
JAEA-Review-2016-011-01.pdf:33.85MBJAEA-Review-2016-011-02.pdf:27.68MB
JAEA has been conducting the Instructor Training Program (ITP) since 1996 under the auspices of MEXT to contribute to human resource development in currently 11 Asian countries in the field of radiation utilization for seeking peaceful use of nuclear energy. ITP consists of Instructor Training Course (ITC), Follow-up Training Course (FTC) and Nuclear Technology Seminars. In the ITP, trainings or seminars relating to technology for nuclear utilization are held in Japan by inviting nuclear related people from Asian countries to Japan and after that, the past trainees are supported during FTC by dispatching Japanese specialists to Asian countries. News Letter is also prepared to provide the broad range of information obtained through the trainings for local people near NPPs in Japan. The present report describes the activities of FY2014 ITP and future challenges for improving ITP more effectively.
Nakamura, Tetsuya*; Imaizumi, Mitsuru*; Sato, Shinichiro; Sugaya, Takeyoshi*; Mochizuki, Toru*; Okano, Yoshinobu*; Oshima, Takeshi
Proceedings of 11th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-11) (Internet), p.73 - 76, 2015/11
The radiation effect on GaAs p-i-n solar cells with quantum dot (QD) in the i-layer was investigated. In a previous work, we particularly noted the degradation of fill-factor (FF) for the QD cells. In this work, to clarify the reason of the FF degradation in QD cells, generation current due to low-energy proton irradiation, which we call ion beam induced current (IBIC), was observed to characterize behavior of the generated minority carrier by the protons in the depletion region where QDs are located. The energy of protons was adjusted to damage the depletion region, and decrease of generation current was measured during the proton irradiation. The results suggest that the serious degradation of FF is caused by a decrease of the carrier collection efficiency in the depletion region due to proton damage.
SGo, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Kobayashi, Motoki*; Kisamori, Keiichi*; Takaki, Motonobu*; Miya, Hiroyuki*; Ota, Shinsuke*; Michimasa, Shinichiro*; Shimoura, Susumu*; et al.
JPS Conference Proceedings (Internet), 6, p.030005_1 - 030005_4, 2015/06
Hwang, J.-G.*; Kim, E.-S.*; Miyajima, Tsukasa*; Honda, Yosuke*; Harada, Kentaro*; Shimada, Miho*; Takai, Ryota*; Kume, Tatsuya*; Nagahashi, Shinya*; Obina, Takashi*; et al.
Nuclear Instruments and Methods in Physics Research A, 753, p.97 - 104, 2014/07
Times Cited Count：7 Percentile：48.18(Instruments & Instrumentation)Kino, Koichi*; Furusaka, Michihiro*; Hiraga, Fujio*; Kamiyama, Takashi*; Kiyanagi, Yoshiaki*; Furutaka, Kazuyoshi; Goko, Shinji*; Hara, Kaoru; Harada, Hideo; Harada, Masahide; et al.
Nuclear Instruments and Methods in Physics Research A, 736, p.66 - 74, 2014/02
Times Cited Count：31 Percentile：91.7(Instruments & Instrumentation)Imaizumi, Mitsuru*; Nakamura, Tetsuya*; Tajima, Michio*; Sato, Shinichiro; Oshima, Takeshi
Proceedings of 39th IEEE Photovoltaic Specialists Conference (PVSC-39) (CD-ROM), p.3243 - 3248, 2013/06
Radiation response of InGaP, GaAs, InGaAs (In=20%) and InGaAs (In=30%) single-junction solar cells, which are the component sbcells of IMM3J cells, were comparatively studied. High-energy electrons (1 MeV) and protons (10 MeV) were irradiated to the four types of the cells. The InGaP cell has the highest radiation resistance to both electrons and protons amongst the four cells as expected. On the other hand, the InGaAs cells have less resistant for Isc compared to InGaP and GaAs cells. However, the resistance of Voc of InGaAs cells is comparable to that of the other two cells. As a general result, InGaAs cells have less radiation resistance to electrons, while they have the resistance against protons equivalent to GaAs cell. These radiation response properties of InGaAs cells are thought to be useful to design radiation resistant IMM3J space solar cells.
Nakamura, Tetsuya*; Imaizumi, Mitsuru*; Sato, Shinichiro; Oshima, Takeshi
Proceedings of 39th IEEE Photovoltaic Specialists Conference (PVSC-39) (CD-ROM), p.0696 - 0700, 2013/06
The estimation method of subcell photocurrent (I
) in multi-junction solar cells using not external quantum efficiency (EQE) but light current-voltage (LIV) characteristics after irradiation is proposed. To obtain I of each subcell, it is necessary to estimate the reverse saturation current density (J
) and shunt resistance (R
) of each subcell using EL and LED bias light (LBL) method. Since estimated I is in agreement with experimental LIV characteristics under illumination of AM0 solar simulator, we can evaluate of complicated maximum power (Pmax) of the inverted metamorphic triple-junction (IMM3J) solar cell after irradiation.
Oshima, Takeshi; Sato, Shinichiro; Imaizumi, Mitsuru*; Nakamura, Tetsuya*; Sugaya, Takeyoshi*; Matsubara, Koji*; Niki, Shigeru*
Solar Energy Materials and Solar Cells, 108, p.263 - 268, 2013/01
Times Cited Count：13 Percentile：49.29(Energy & Fuels)GaAs solar cells which have a PiN structure with 50 self-organized In
Ga
As Quantum Dot (QD) layers were irradiated with 1 MeV electrons up to 1
10
/cm
. After irradiation at 110/cm, the remaining factor of I
, V
and P
for the InGaAs 50 QD solar cell becomes 80, 90 and 55% of the initial values, respectively. On the other hand, those values for non QD GaAs solar cells decrease to 95, 80 and 63% of the initial values, respectively. Since the i-layer for the 50 QD solar cells (1.1 
m) is thicker than the non QD solar cells (660 nm), the larger degradation of I for the 50 QD solar cells than the non QD ones can be interpreted in terms that the carrier recombination in the i-layer for the 50 QD solar cells is larger than that for the non QD solar cells. For V, the 50 QD solar cells showes better radiation resistance than the non QD solar cells. Furthermore, the annealing behavior of the electrical characteristics for the 50 QD and the non QD solar cells was investigated at RT under AM 0 immediately after the irradiation. As a result, the recovery of the electrical characteristics for both solar cells was observed, and the GaAs solar cells shows relatively larger recovery compared to the 50 QD solar cells. Although the mechanism of this recovery has not yet been clarified, the origin of this recovery is thought not to come from the existence of QDs because the GaAs solar cell without QD layers also shows the recovery.
Nakamura, Tetsuya*; Imaizumi, Mitsuru*; Sugai, Mitsunobu*; Sato, Shinichiro; Oshima, Takeshi
Proceedings of 10th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-10) (Internet), p.48 - 51, 2012/12
Recently a new method was proposed that estimating the current-voltage (IV) characteristics of subcells in a multi-junction (MJ) solar cell by using electroluminescence (EL). The estimated IV characteristics of electron-irradiated MJ solar cell from the IV curve obtained from each subcell agreed well with the actual dark IV (DIV) and light IV (LIV) characteristics, except for series resistance (
) and shunt resistance (
). of a MJ cells and of subcells can be also clarified through measurement LIV characteristics using color bias lights and circuit simulation program. In this work, we applied this method to InGaP/GaAs dual-junction (2J) solar cells irradiated with electrons. As a result, we succeeded to predict the degradation curve of maximum power of the 2J solar cell where the current-limiting subcell changes from InGaP to GaAs subcell using degradation curve of each parameter.
Nakamura, Tetsuya*; Imaizumi, Mitsuru*; Sato, Shinichiro; Oshima, Takeshi
Proceedings of 38th IEEE Photovoltaic Specialists Conference (PVSC-38) (CD-ROM), p.002846 - 002850, 2012/00
Roensch et al. recently proposed a new method of estimating the current-voltage (IV) characteristics of subcells in a multi-junction (MJ) solar cell by using electroluminescence (EL). The estimated IV characteristics of a proton-irradiated MJ solar cell from the IV curve obtained from each subcell agreed well with the actual dark IV (DIV) and light IV (LIV) characteristics, except for series resistance (
) and shunt resistance (). This method can also clarify of a MJ cells and Rsh of subcells through circuit simulation program. In this work, we applied this method to InGaP/GaAs dual-junction (2J) solar cells in order to obtain the IV characteristics of the InGaP top subcells and GaAs bottom subcells before and after proton irradiation with various fluences. In addition, we succeeded to predict the degradation curve of maximum power (
) of the 2J solar cell where the current-limiting subcell changes from InGaP to GaAs subcell.
Morioka, Chiharu*; Shimazaki, Kazunori*; Kawakita, Shiro*; Imaizumi, Mitsuru*; Yamaguchi, Hiroshi*; Takamoto, Tatsuya*; Sato, Shinichiro; Oshima, Takeshi; Nakamura, Yosuke*; Hirako, Keiichi*; et al.
Progress in Photovoltaics; Research and Applications, 19(7), p.825 - 833, 2011/11
Times Cited Count：24 Percentile：68.28(Energy & Fuels)Nakamura, Yasuyuki; Sano, Kazuya; Morishita, Yoshitsugu; Maruyama, Shinichiro*; Tezuka, Shinichi*; Ogane, Daisuke*; Takashima, Yuji*
Journal of Engineering for Gas Turbines and Power, 133(6), p.064501_1 - 064501_3, 2011/06
Times Cited Count：1 Percentile：11.94(Engineering, Mechanical)Abrasive water jet (AWJ), is to shoot the abrasive mixed with high-pressure water to the material for cutting, can cut most materials like metals and concretes in water with long stand-off means the length from the cutting head to the material for cutting. On the other hand, AWJ is required to reduce an amount of the abrasive because it becomes the waste. It is also difficult to monitor the cutting condition by any visual methods like a TV camera in the water becoming cloudy by both used abrasive and cut metal grit. For solving these issues, some cutting tests were conducted and (1) It was possible to predict an optimal supply rate of abrasive by considering the conservation of momentum between the water jet and the abrasive. (2) It was also possible to judge whether the material could be cut successfully or not by detecting the change in the frequency characteristics of vibration or sound caused during the cutting process.
Kino, Koichi*; Furusaka, Michihiro*; Hiraga, Fujio*; Kamiyama, Takashi*; Kiyanagi, Yoshiaki*; Furutaka, Kazuyoshi; Goko, Shinji*; Harada, Hideo; Harada, Masahide; Kai, Tetsuya; et al.
Nuclear Instruments and Methods in Physics Research A, 626-627, p.58 - 66, 2011/01
Times Cited Count：47 Percentile：95.25(Instruments & Instrumentation)We measured the energy spectra and spatial distributions of the neutron beam of ANNRI beamline at the Japan Proton Accelerator Research Complex / Materials and Life Science Experimental Facility (J-PARC/MLF). Our research team designed and built this beamline to measure nuclear data with high precision. The measurements were performed on three types of beams provided by the beamline in the neutron energy range of 1.5 meV to 10 keV. The energy spectra show a typical feature of para-hydrogen moderator, and the absolute intensities almost agree with predictions based on both a simulation calculation of the JSNS (Japan Spallation Neutron Source) and a neutron transmission calculation of the beamline. The available neutron intensities at 21.5 m are 7.510
, 1.610
, and 1.110 n/cm/sec in the energy ranges of 1.5-25 meV, 0.9-1.1 eV, and 0.9-1.1 keV, respectively, under the 17.5 kW JSNS operation. The measured spatial distributions of the beams formed by three different collimators are consistent with those expected from the collimator-system design of the beamline. The beam sizes in FWHM are about 29, 14, and 11 mm for the three different beam collimators. The edges of the spatial distributions are relatively sharp, enabling us to measure the nuclear data successfully.
Maekawa, Fujio; Harada, Masahide; Oikawa, Kenichi; Teshigawara, Makoto; Kai, Tetsuya; Meigo, Shinichiro; Oi, Motoki; Sakamoto, Shinichi; Takada, Hiroshi; Futakawa, Masatoshi; et al.
Nuclear Instruments and Methods in Physics Research A, 620(2-3), p.159 - 165, 2010/08
Times Cited Count：74 Percentile：97.56(Instruments & Instrumentation)The J-PARC 1-MW pulsed spallation neutron source JSNS was successfully launched on 30th of May 2008. To demonstrate the unique features of the moderator design and the neutronic performance of JSNS the neutron spectral intensity, absolute neutron flux, and time structure of the neutron pulse shapes etc have been measured using several neutron instruments since then. The measured energy spectra clearly revealed the feature of the para-hydrogen, as expected when designing the moderator. The measured neutron flux below 0.4 eV agreed with the corresponding design value within 
20%, thus suggesting that the JSNS design calculations to have been reliable. World-class high-resolution diffraction data could be recorded due to the suitability of design of the moderators and the instruments. Another world-class high-intensity neutron flux was also capable of being demonstrated due to the unique design of the large cylindrical coupled moderator.
