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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：29.36(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：29.36(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.
Adachi, Motoyasu; Hirayama, Hiroshi; Shimizu, Rumi; Sato, Katsuya; Narumi, Issey*; Kuroki, Ryota
Protein Science, 23(10), p.1349 - 1358, 2014/10
Times Cited Count：10 Percentile：25.91(Biochemistry & Molecular Biology)Pleiotropic protein promoting DNA repair A (PprA) is a key protein that facilitates the extreme radioresistance of . To clarify the role of PprA in the radioresistance mechanism, the interaction between recombinant PprA expressed in Escherichia coli with several double-stranded DNAs was investigated. In a gel-shift assay, the band shift of supercoiled pUC19 DNA caused by the binding of PprA showed a bimodal distribution, which was promoted by the addition of 1 mM Mg, Ca, or Sr ions. The dissociation constant of the PprA-supercoiled pUC19 DNA complex, calculated from the relative portions of shifted bands, was 0.6 M with a Hill coefficient of 3.3 in the presence of 1 mM Mg acetate. This indicates that at least 281 PprA molecules are required to saturate a supercoiled pUC19 DNA, which is consistent with the number of bound PprA molecules estimated by the UV absorption of the PprA-pUC19 complex purified by gel filtration. This saturation also suggests linear polymerization of PprA along the dsDNA. On the other hand, the bands of linear dsDNA and nicked circular dsDNA that eventually formed PprA complexes did not saturate, but created larger molecular complexes when the PprA concentration was greater than 1.3 M. This result implies that DNA-bound PprA aids association of the termini of damaged DNAs, which is regulated by the concentration of PprA.
Bando, Kyoko*; Saito, Takeru; Sato, Koichi*; Tanaka, Tomoaki*; Dumeignil, F.*; Imamura, Motoyasu*; Matsubayashi, Nobuyuki*; Shimada, Hiromichi*
Topics in Catalysis, 18(1-2), p.59 - 65, 2002/01
no abstracts in English
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.
CF experiment at J-PARC MLFOkutsu, 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 discussed how to observe a kinetic energy distribution of a recycling muon emitted after CF reaction.
Miyashita, Konan*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
no journal, ,
To observe a kinetic energy distribution of a recycling muon emitted after CF reaction, it is necessary to guide the recycling muons to a detector. In this work, we simulated the muon transportation using PHITS code and designed an experimental system.
Konishi, Ren*; Okutsu, Kenichi*; Kino, Yasushi*; Sasaki, Kyosuke*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; et al.
no journal, ,
When muons are injected into a deuterium thin film target, muon molecules are formed. The muons released after intramolecular fusion (recycling muons) are important for the development of slow muon beams. In this study, corresponding to an experiment in which recycling muons are transported using a coaxial transport tube, the energy distribution of scattered muons, muons after deceleration, and background radiation due to bremsstrahlung by decay electrons and neutrons are analyzed by numerical simulations.
Adachi, Motoyasu; Tamada, Taro; Sato, Katsuya*; Narumi, Issei; Kuroki, Ryota
no journal, ,
The resistance of Deinococcus radiodurans to 
-ray is 1000 times higher than that of human cells. PprA is the novel protein which promotes repairing DNA, and play a key role in the ability to resist to the radiation. The characterization of PprA have showed: (1) that the expression of PprA is controlled under another novel protein of PprI (2) that PprA promotes ligase reaction: (3) that pprA exhibits the ability to bind on DNA. In this study, our objective is the crystal structure analysis of PprA to reveal its structure-function relationships and for application as genetic and clinical tools. Here, we constructed the E. coli expression and purification system of PprA. Using the purified PprA, some small crystals in size were obtained after screening of conditions for crystalization. Beased on the analyses of DNA-PprA interaction, we showed that 280 molecules of PprA at least can bind on a DNA molecule of pUC19 plasmid (2686bp). In addition, we indicated that several DNA-PprA complexes may form higher complex, when DNA includes terminal end or nick (the cleaved part on a DNA strand). These results are important knowledge in molecular assembly and function of PprA.
Adachi, Motoyasu; Tamada, Taro; Sato, Katsuya; Yura, Kei; Narumi, Issei; Kuroki, Ryota
no journal, ,
no abstracts in English
Miyashita, Konan*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
no journal, ,
To measure the kinetic energy of a recycling muon, we discussed how to reduce the background radiation and the trajectory of the transported recycling muons by simulation code.
Nakashima, Ryota*; Okutsu, Kenichi*; Kino, Yasushi*; Miyashita, Konan*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
no journal, ,
To detect a recycling muon emitted after muon catalyzed fusion reaction, it is necessary to guide the recycling muons from the target to a detector in a low background area. In this work, we simulated the muon transportation using SIMONS and PHITS codes and designed an experimental system.
Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
no journal, ,
A muon is one of elementary particles which is known to weight 207 times more than an electron. A nuclear fusion reaction occurs in a muonic molecule which consists of two hydrogen isotope nuclei and a muon because the muon binds more tightly than electron. Since the muon does not directly participate in the fusion reaction, the reaction is called muon catalyzed fusion (CF). The muon released after the reaction is called a "recycling muon", and maintains the molecular orbital information when the muonic molecule formed. Therefore, information of the muon wavefunction can be investigated by observing the energy distribution of the recycling muon. We will report the experimental setup for measuring the energy distribution of the recycling muons after the nuclear 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 catalyzed fusion (CF) is a cyclic reaction where a negatively charged muon itself acts like a catalyst of nuclear fusion between hydrogen isotopes, such as 
or 
. In this work, we have investigated the shape and characteristic of solid hydrogen isotope target.
Miyashita, Konan*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
no journal, ,
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 this work, we have designed the shape of the thermal shield to reduce the background noise.
Konishi, Ren*; Okutsu, Kenichi*; Kino, Yasushi*; Sasaki, Kyosuke*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; et al.
no journal, ,
We are attempting to observe regenerative muons emitted from the surface of a solid hydrogen thin film by muon-catalyzed fusion by irradiating the film with muons that have the same charge as electrons and 207 times the mass of electrons. The main background factors in detecting regenerative muons are scattered muons from the accelerator, which are slowed down to the same level as regenerative muons by the target, and bremsstrahlung generated by the components of the device. The results show that there is little scattering within the solid hydrogen, and that the dominant slowing down process is at the Al foil upstream of the solid hydrogen target. The energy distribution of Bremsstrahlung at the X-ray detection position will be reported.
Ikemoto, Megumi*; Somekawa, Jun*; Neki, Arata*; Konishi, Ren*; Nakashima, Ryota*; Okutsu, Kenichi*; Kino, Yasushi*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; et al.
no journal, ,
no abstracts in English
Yamada, Mitsugu; Adachi, Motoyasu; Sato, Katsuya; Tamada, Taro; Yura, Kei*; Kuroki, Ryota; Narumi, Issei
no journal, ,
no abstracts in English
Yoshimura, Naoki*; Sato, Rena*; Adachi, Motoyasu; Kuroki, Ryota; Kato, Etsuko*; Kidokoro, Shunichi*
no journal, ,
The change of the thermodynamic functions accompanying the binding of a single stranded oligo-DNA with a sequence of TCTTTTT to cold shock protein from 
HB8 was evaluated by isothermal titration calorimetry, and the three-dimensional structure of the complex was determined by X-ray crystallography. The binding was almost approximated by a two-state model and found to be stabilized by large negative enthalpy change due to the stacking interaction between the bases of the DNA and the aromatic side chains of the protein.
