Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Komuro, Yo; Hirade, Tetsuya; Suzuki, Ryoichi*; Odaira, Toshiyuki*; Muramatsu, Makoto*
no journal, ,
The annihilation 
rays from the para-pojitoronium (p-Ps) state gives narrower Doppler broadening. The broader Doppler broadening was observed at very young age region that is mainly from the annihilation process of p-Ps. It was explained by the delayed Ps slowing down and the delayed Ps formation. We have successfully obtained the experimental evidence of the delayed Ps formation.
Taguchi, Mitsumasa; Baldacchino, G.*; Pin, S.*; Vigneron, G.*; Hichel, B.*; Kojima, Takuji
no journal, ,
no abstracts in English
Asano, Masaharu; Chen, J.; Yamaki, Tetsuya; Yoshida, Masaru
no journal, ,
To prepare proton-conducting membranes with an excellent mechanical characteristic, a mixture of styrene and divinylbenzene was grafted into various base materials such as CF2-derivatives (PTFE, PFA and FEP) and CF2/CH2-derivatives (ETFE and PVDF). It was found that the introduction of graft-chains into CF2/CH2-derivatives was easier compared with that of CF2-derivatives. These derivatives that introduced the graft-chains were then sulfoanted, in order to determine the tensile strength, as a resulting of higher tensile strength for sulfonated CF2/CH2-derivatives
Yang, J.*; Taguchi, Mitsumasa; Kondo, Takafumi*; Yoshida, Yoichi*; Shibata, Hiromi*; Namba, Hideki; Kojima, Takuji
no journal, ,
no abstracts in English
-xylene diamine-6 by ion-beam-induced graft polymerizationSuzuki, Yasuyuki; Yamaki, Tetsuya; Asano, Masaharu; Yoshida, Masaru
no journal, ,
We prepared polymer electrolyte membranes by the ion-beam-induced graft polymerization of sodium 
-styrenesulfonate (SSS) into nylon -xylene diamine-6 (NMXD6) films. The grafting yield was controlled by adjusting the grafting conditions such as reaction times, temperatures, ion species and fluences of the pre-irradiated ions. The membranes prepared at 50 and 60
C exhibited homogeneous distribution of sulfonic acid groups across their transverse plane. The proton conductivity of the wet membranes at room temperature ranged from 0.0021 to 0.054 S/cm in the direction of thickness, depending on their ion exchange capacity.
Hiroki, Akihiro; Yamaki, Tetsuya; Asano, Masaharu; Yoshida, Masaru
no journal, ,
Films of various fluoropolymers such as ETFE and PTFE were bombarded with swift heavy ions to produce a cylindrical damage zone along the incident axis. The active species generated in this so-called ion track were used to initiate the grafting of styrene, and subsequently the graft chains were sulfonated to produce nano-scaled electrolyte regions. According to a theoretical calculation, the diameter of the ion track in a PTFE film irradiated with 
Ar (3.8 MeV/n) and 
Xe (3.5 MeV/n) ions was estimated to be about 120 and 215 nm, respectively. As the ion track was small, the proton conductivity of the resulting polyelectrolyte membranes became large.
Miyazaki, Toyoaki*; Katsumura, Yosuke*; Lin, M.*; Muroya, Yusa*; Taguchi, Mitsumasa; Asano, Masaharu; Yoshida, Masaru
no journal, ,
To clarify radiation-induced decomposition of benzene in high-temperature and supercritical water, -radiolysis study at elevated temperature has been performed. Products obtained are phenol, biphenyl and isomers of dihydroxycyclohexadienls. In addition to phenol and biphenyl, carbon dioxide, carbon monoxide and hydrogen are obtained as major products at supercritical condition. This result indicates that mechanism of benzene decomposition is changed by elevating temperature.
-ray irradiation effects on polymeric materials in superconducting magnets for the J-PARC neutrino experiment, 2; Gas evolutionIdesaki, Akira; Gokan, Mayo*; Morishita, Norio; Ito, Hisayoshi; Nakamoto, Tatsushi*; Ogitsu, Toru*; Ohata, Hirokatsu*; Kimura, Nobuhiro*; Makida, Yasuhiro*; Yamamoto, Akira*
no journal, ,
Irradiation effect on polymeric materials used in the superconducting magnets for the J-PARC neutrino beam line was studied with respect to gas evolution. The polymeric materials were irradiated by -ray at 77K. It was found that hydrogen gas evolves mainly from the polymeric materials, and that the amount of hydrogen from whole superconducting magnet system per 1 year is 0.37mol. Furthermore, it was found that the amount of gas evolution increases with increasing in the storage time at room temperature after the irradiation at 77K.
-ray irradiation effects on polymeric materials in superconducting magnets for the J-PARC neutrino experiment, 1; Mechanical propertiesIdesaki, Akira; Nakamoto, Tatsushi*; Ogitsu, Toru*; Ohata, Hirokatsu*; Kimura, Nobuhiro*; Makida, Yasuhiro*; Yamamoto, Akira*; Gokan, Mayo*; Morishita, Norio; Ito, Hisayoshi
no journal, ,
Radiation resistance of polymeric materials used in superconducting magnets for a 50 GeV-750 kW proton beam line for the J-PARC neutrino experiment was studied with respect to mechanical properties. Specimens were irradiated by rays with the maximum dose beyond 10 MGy. It was verified that the polymeric materials have the sufficient radiation resistance, and the degradation of their mechanical properties after the 10 years operation was estimated to be negligible.