Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
-edge for Ce in bauxites using transition-edge sensors; Implications for Ti-rich geological samplesLi, W.*; Yamada, Shinya*; Hashimoto, Tadashi; Okumura, Takuma*; Hayakawa, Ryota*; Nitta, Kiyofumi*; Sekizawa, Oki*; Suga, Hiroki*; Uruga, Tomoya*; Ichinohe, Yuto*; et al.
Analytica Chimica Acta, 1240, p.340755_1 - 340755_9, 2023/02
Times Cited Count：2 Percentile：31.9(Chemistry, Analytical)no abstracts in English
Okutsu, Kenichi*; Yamashita, Takuma*; Kino, Yasushi*; Miyashita, Konan*; Yasuda, Kazuhiro*; Oka, Toshitaka; Okada, Shinji*; Sato, Motoyasu*
JJAP Conference Proceedings (Internet), 9, p.011003_1 - 011003_7, 2023/00
Muon catalyzed fusion (
CF) is a cyclic reaction where a negatively charged muon itself acts like a catalyst of nuclear fusion between hydrogen isotopes. In the CF reaction, muon transfer from deuteron to triton and muonic molecular formation are rate-limiting processes. In this work, we have investigated the role of resonance states of muonic molecule in the CF which affects the muonic deuterium atom population. Solving simultaneous rate equations numerically by the fourth-order Runge-Kutta method, we determined the muonic molecular formation rate so that the number of fusion events reproduces a latest experimental result. It is revealed that the resonance states play a role to enhance the fusion rate by accelerating the de-excitation of the muonic atoms.
Okutsu, Kenichi*; Yamashita, Takuma*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
Fusion Engineering and Design, 170, p.112712_1 - 112712_4, 2021/09
Times Cited Count：3 Percentile：45.99(Nuclear Science & Technology)A muonic molecule which consists of two hydrogen isotope nuclei (deuteron (d) or tritium (t)) and a muon decays immediately via nuclear fusion and the muon will be released as a recycling muon, and start to find another hydrogen isotope nucleus. The reaction cycle continues until the muon ends up its lifetime of 2.2 s. Since the muon does not participate in the nuclear reaction, the reaction is so called a muon catalyzed fusion (CF). The recycling muon has a particular kinetic energy (KE) of the muon molecular orbital when the nuclear reaction occurs. Since the KE is based on the unified atom limit where distance between two nuclei is zero. A precise few-body calculation estimating KE distribution (KED) is also in progress, which could be compared with the experimental results. In the present work, we observed recycling muons after CF reaction.
Yamashita, Takuma*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
Fusion Engineering and Design, 169, p.112580_1 - 112580_5, 2021/08
Times Cited Count：3 Percentile：45.99(Nuclear Science & Technology)A muon () having 207 times larger mass of electron and the same charge as the electron has been known to catalyze a nuclear fusion between deuteron (d) and triton (t). These two nuclei are bound by and form a muonic hydrogen molecular ion, dt. Due to the short inter-nuclear distance of dt, the nuclear fusion, d +t
+ n + 17.6 MeV, occurs inside the molecule. This reaction is called muon catalyzed fusion (CF). Recently, the interest on CF is renewed from the viewpoint of applications, such as a source of high-resolution muon beam and mono-energetic neutron beam. In this work, we report a time evolution calculation of CF in a two-layered hydrogen isotope target.
Okumura, Takuma*; Azuma, Toshiyuki*; Bennet, D. A.*; Caradonna, P.*; Chiu, I.-H.*; Doriese, W. B.*; Durkin, M. S.*; Fowler, J. W.*; Gard, J. D.*; Hashimoto, Tadashi; et al.
IEEE Transactions on Applied Superconductivity, 31(5), p.2101704_1 - 2101704_4, 2021/08
Times Cited Count：1 Percentile：11.15(Engineering, Electrical & Electronic)A superconducting transition-edge sensor (TES) microcalorimeter is an ideal X-ray detector for experiments at accelerator facilities because of good energy resolution and high efficiency. To study the performance of the TES detector with a high-intensity pulsed charged-particle beam, we measured X-ray spectra with a pulsed muon beam at the Japan Proton Accelerator Research Complex (J-PARC) in Japan. We found substantial temporal shifts of the X-ray energy correlated with the arrival time of the pulsed muon beam, which was reasonably explained by pulse pileup due to the incidence of energetic particles from the initial pulsed beam.
X raysOkumura, Takuma*; Azuma, Toshiyuki*; Bennet, D. A.*; Caradonna, P.*; Chiu, I. H.*; Doriese, W. B.*; Durkin, M. S.*; Fowler, J. W.*; Gard, J. D.*; Hashimoto, Tadashi; et al.
Physical Review Letters, 127(5), p.053001_1 - 053001_7, 2021/07
Times Cited Count：13 Percentile：79.44(Physics, Multidisciplinary)We observed electronic X rays emitted from muonic iron atoms using a superconducting transition-edge-type sensor microcalorimeter. The energy resolution of 5.2 eV in FWHM allowed us to observe the asymmetric broad profile of the electronic characteristic 
and 
X rays together with the hypersatellite X rays around 6 keV. This signature reflects the time-dependent screening of the nuclear charge by the negative muon and the 
-shell electrons, accompanied by electron side-feeding. Assisted by a simulation, this data clearly reveals the electronic - and -shell hole production and their temporal evolution during the muon cascade process.
Nagae, Daisuke*; Abe, Yasushi*; Okada, Shunsuke*; Omika, Shuichiro*; Wakayama, Kiyoshi*; Hosoi, Shun*; Suzuki, Shinji*; Moriguchi, Tetsuro*; Amano, Masamichi*; Kamioka, Daiki*; et al.
Nuclear Instruments and Methods in Physics Research A, 986, p.164713_1 - 164713_7, 2021/01
Times Cited Count：5 Percentile：65.59(Instruments & Instrumentation)Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Nagaoka, Mika; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.
JAEA-Review 2017-001, 115 Pages, 2017/03
JAEA-Review-2017-001.pdf:3.57MB
Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2015. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.
Fukushima, Mineo; Kawatsuma, Shinji; Okada, Takashi
Proceedings of American Nuclear Society Embedded Topical on Decommissioning, Decontamination and Reutilization and Technology Expo (DD&R 2012) (DVD-ROM), p.67 - 68, 2012/06
The accident on Fukushima Daiichi Nuclear Power Plant has been occurred by the TSUNAMI that generated form Great East Japan Earthquake happened in 11th March 2011. Just after the earthquake, JAEA is assisting activities concerning the accident of the Fukushima No.1 Nuclear Power Station including teleoperation, decontamination and radiation monitoring in the site. JAEA had already developed some robotics, RESQ series, for radiological emergency response in 2001, after JCO criticality accidents occurred. However, they could not work for the NPP because of lack of maintenance. According to the situation and condition of the FUKUSHIMA-DAIICHI accident, JAEA has modified above mentioned robotics and prepared supporting equipments like as Robotics control vehicles. JAEA has provided Robotics and Robotics Control vehicles to TEPCO and is continuously supporting Tokyo Electric Company for plant restoration.
Kawatsuma, Shinji; Fukushima, Mineo; Okada, Takashi
Industrial Robot; An International Journal, 39(5), p.428 - 435, 2012/00
Times Cited Count：120 Percentile：95.92(Engineering, Industrial) molecular beamsTeraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke; Takakuwa, Yuji*; Ogawa, Shuichi*; Ishizuka, Shinji*; Okada, Michio*; Fukuyama, Tetsuya*; Kasai, Toshio*
Hoshako, 18(5), p.298 - 309, 2005/09
Representative research results in surface reaction dynamics, performed at a surface chemistry experimental station installed in the JAEA soft X-ray beamline in the SPring-8, were reviewed. As a research result in JAEA, SiO desorption mechanisms in the Si(001) oxidation at high temperature were introduced. As a collaboration with Osaka University on oxidation reaction dynamics of Cu, collision-induced atom absorption process was introduced. As a collaboration with Tohoku University on Ti(0001) oxidation reaction dynamics, it was introduced that two peaks, found in an incident energy dependence of initial sticking probability, were corresponding to potential energy barriers of dissociative adsorption of O molecules.
Okawa, Yoshinao; Kashimura, Shinji*; Murano, Yoshihiro*; Ito, Michio*; Okada, Kenichi*; Izumi, Keisuke*; Tsuchida, Takashi*
Dai-19-Kai Denki Setsubi Gakkai Zenkoku Taikai Koen Rombunshu, p.415 - 416, 2001/00
no abstracts in English
Okada, Takashi; Kawatsuma, Shinji; Fukushima, Mineo; Igarashi, Miyuki; Nakai, Koji; Mimura, Ryuji; Kanayama, Fumihiko
no journal, ,
Due to Tohoku Pacific Ocean earthquake and tsunami in 11 March in 2011, Tokyo Electric Power Co. Fukushima Daiichi Nuclear Power Station lost all power and has occurred accidents for failure of core cooling function. In Japan Atomic Energy Agency it was remodeled the nuclear disaster robot, was developed 
-ray visualization equipment and has been supporting the accident recovery. This paper is described the lessons learned from the supporting with the nuclear disaster robots and the -ray visualization equipment.
Kawatsuma, Shinji; Okada, Takashi; Fukushima, Mineo
no journal, ,
Japan Atomic Energy Agency developed Nuclear Disaster Response Robotics in 2001 after JCO criticality accidents occurred. It is very sorry that Nuclear Disaster Response Robotics could not work when the Fukushima-Daiichi accident occurred by a big earthquake and a huge Tsunami on March 11th 2011. According to the situation and condition of the Fukushima-Daiichi accident, JAEA has modified above mentioned Nuclear Disaster Response Robotics and prepared supporting equipments like as Robotics Control vehicles. JAEA has provided Robotics and Robotics Control vehicle to TEPCO and is continuously supporting TEPCO for plant restoration. This paper summarize JAEA ROBOTICS Emergency Response to Fukushima-Daiichi accident and describe lessons learned.
Kawatsuma, Shinji; Okada, Takashi; Fukushima, Mineo; Nakai, Koji; Mimura, Ryuji; Kanayama, Fumihiko
no journal, ,
no abstracts in English
Okada, Takashi; Nakai, Koji; Igarashi, Miyuki; Kawatsuma, Shinji
no journal, ,
Japan Atomic Energy Agency developed a robotic control vehicle for supporting the accident recovery in the Fukushima Daiichi Nuclear Power Station. The developed robotic control vehicle can measure radiation using a cam and a robot with a radiation sensor. A heavily shielded operation box was built for reducing the exposure of radiation.
ray imaging system and reconnaissance platformMimura, Ryuji; Kanayama, Fumihiko; Okada, Takashi; Kawatsuma, Shinji
no journal, ,
no abstracts in English
Yamashita, Takuma*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
no journal, ,
A muon () having 207 times larger mass of electron and the same charge as the electron has been known to catalyze a nuclear fusion (CF) between deuteron (d) and triton (t). In this work, we have solved simultaneous reaction rate equations by the 4th-order Runge-Kutta method for the jointed CF cycles in the two layers (H/D and D/T). The T concentration to maximize the intensities of fusion neutrons and muons emitted to the vacuum will be discussed.
CF experiment at J-PARC MLFNatori, Hiroaki*; Doiuchi, Shogo*; Ishida, Katsuhiko*; Kino, Yasushi*; Miyake, Yasuhiro*; Miyashita, Konan*; Nakashima, Ryota*; Nagatani, Yukinori*; Nishimura, Shoichiro*; Oka, Toshitaka; et al.
no journal, ,
A muonic molecule which consists of muon and two hydrogen isotope nuclei (deuteron (d) or tritium (t)) decays immediately via nuclear fusion (
CF) and the muon will be released as a recycling muon. We attempted to use these muons to develop the scanning muon microscope. In this work, we will report the detection of neutron which emits during the CF reaction.
Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
no journal, ,
Muon catalized fusion (CF) is expected to be a high-quality muon beam source for undestructive measurement and a monoenergetic neutron source. In this work, we attemped to observe a released muon after intermolecular nuclear reaction using muonic X-ray.
