Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Idesaki, Akira; Gokan, Mayo*; Morishita, Norio; Ito, Hisayoshi; Nakamoto, Tatsushi*; Ogitsu, Toru*; Ohata, Hirokatsu*; Kimura, Nobuhiro*; Makida, Yasuhiro*; Yamamoto, Akira*
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 32, 2007/02
Radiation resistance of polymeric materials used in the superconducting magnets installed for the J-PARC neutrino beam line was studied with respect to gas evolution. The polymeric materials were irradiated by rays at 77K. It was found that hydrogen gas evolved mainly from the polymeric materials, and the amount of hydrogen from whole superconducting magnet system per 1 year was estimated to be 0.37mol. This amount of hydrogen is low enough to be removed by a hydrogen absorbing apparatus. Therefore, the influence of hydrogen evolved from the magnet system on the operation of the helium purifying system can be negligible.
Nakamoto, Tatsushi*; Ohata, Hirokatsu*; Ogitsu, Toru*; Kimura, Nobuhiro*; Makida, Yasuhiro*; Yamamoto, Akira*; Idesaki, Akira; Gokan, Mayo*; Morishita, Norio; Ito, Hisayoshi
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 31, 2007/02
Radiation resistance of organic 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 cooled at a liquid nitrogen temperature of 77 K were irradiated by rays. The flexural strength of glass-fiber reinforced plastics (GFRPs), the tear strength of polyimide films and the tensile strength of adhesive films were evaluated. It was verified that the organic materials used in the superconducting magnets have the sufficient radiation resistance, and the degradation of thier mechanical properties after the 10 years operation was estimated to be negligible.
Makida, Yasuhiro*; Ohata, Hirokatsu*; Okamura, Takahiro*; Ogitsu, Toru*; Nakamoto, Tatsushi*; Kimura, Nobuhiro*; Idesaki, Akira; Gokan, Mayo*; Morishita, Norio
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 34, 2007/02
A string of superconducting magnets is to be set at an arc section of the J-PARC neutrino beam line. To keep the magnets at superconducting condition, a helium cryogenic facility is to be constructed. Parts of cryogenic devices are located beside the magnets, so thier resistance to radiation with predicted dose of 1 MGy in maximum must be assured. A cryogenic control valve is one of the active devices used in the radio-active area, and its radio-proof characteristics is improved by (1) exchaging intolerant materials by proof ones, (2) moving the feed back control circuit unit including electronics from the valve body to a low radio-active area. Two prototype valves, a tuning valve and a Gauzky relief valve, have been prepared and have been tested by using the Cobalt 60 irradiation facility in JAEA. Actual operations of the both prototypes have been checked at the irradiation test bench, and they were successfully operated after irradiation of 1 MGy.
Idesaki, Akira; Morishita, Norio; Ito, Hisayoshi; Kamiya, Tomihiro; Nakamoto, Tatsushi*; Kimura, Nobuhiro*; Makida, Yasuhiro*; Ogitsu, Toru*; Ohata, Hirokatsu*; Yamamoto, Akira*
AIP Conference Proceedings 824, p.330 - 334, 2006/03
Polyimide films and glass fiber reinforced plastics (GFRPs) are used as insulating or structural materials for superconducting magnets in a neutrino beam line of the Japan Proton Accelerator Research Complex (J-PARC). It is indispensable to evaluate radiation resistance of these materials, because they are required to keep their electrical and mechanical properties in a high radiation field of 30 kGy/year at low temperature of 4 K. In this work, the gas evolution resulting from chemical reactions induced in the polyimide films and GFRPs by ray irradiation at 77 K was investigated. It was found that the main component of the evolved gas is hydrogen. The amount of hydrogen evolved from the superconducting magnet system used in the neutrino beam line was estimated to be 0.37 mol/year (0.01 L/year as the volume of liquid hydrogen). It indicates that the hydrogen evolved from the organic materials does not influence on the operation of the helium purifying system.
Nakamoto, Tatsushi*; Idesaki, Akira; Morishita, Norio; Ito, Hisayoshi; Kamiya, Tomihiro; Kimura, Nobuhiro*; Makida, Yasuhiro*; Ogitsu, Toru*; Ohata, Hirokatsu*; Yamamoto, Akira*
AIP Conference Proceedings 824, p.225 - 232, 2006/03
Radiation resistance with respect to mechanical properties of organic materials used in the superconducting magnets for the 50 GeV - 750 kW proton beam line for the J-PARC neutrino experiment was studied. Specimens cooled at liquid nitrogen temperature of 77 K were irradiated by gamma rays beyond 10 MGy. The flexural strength of glass-fiber reinforced plastics (GFRPs), the tear strength of polyimide films and the tensile lap-shear strength of adhesive films were evaluated. It was verified that the organic materials used in the superconducting magnet have a sufficient radiation resistance, and the degradation of their mechanical properties after 10 years operation was estimated to be negligible.
Nakamoto, Tatsushi*; Ohata, Hirokatsu*; Ogitsu, Toru*; Kimura, Nobuhiro*; Makida, Yasuhiro*; Yamamoto, Akira*; Idesaki, Akira; Ito, Hisayoshi; Morishita, Norio
no journal, ,
A Superconducting magnet system will be adopted for the J-PARC neutrino beam line. GFRPs whose matrices are phenol resin and epoxy resin, and polyimides are used as structural materials and electrical insulation. Radiation resistance of these polymeric materials is very important, because they are exposed to high radiation field. In this work, specimens were irradiated by rays with the maximum dose beyond 10MGy at liquid nitrogen temperature (77K), and the properties of gas evolution and mechanical strength were investigated. It was verified experimentally that the polymeric materials have sufficient radiation resistance for the using in the J-PARC neutrino beam line.
Makida, Yasuhiro*; Iida, Masahisa*; Ohata, Hirokatsu*; Okamura, Takahiro*; Ogitsu, Toru*; Kimura, Nobuhiro*; Tanaka, Kenichi*; Nakamoto, Tatsushi*; Yamamoto, Akira*; Idesaki, Akira; et al.
no journal, ,
A Superconducting magnet system will be adopted for the J-PARC neutrino beam line. Since the magnet system will be exposed to high radiation field, the radiation resistance of a cryostat is very important. We have developed radio-proof control valve and relief valve by selection of some parts and separation of the positioner. In this work, the developed valves were worked under the ray irradiation, and it was found that the valves show the radiation resistance above 1MGy.
Idesaki, 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.
Idesaki, 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.
Idesaki, 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 0.37 mol.
Nakamoto, Tatsushi*; Ohata, Hirokatsu*; Ogitsu, Toru*; Kimura, Nobuhiro*; Makida, Yasuhiro*; Yamamoto, Akira*; Idesaki, Akira; Gokan, Mayo*; Morishita, Norio; Ito, Hisayoshi
no journal, ,
A Superconducting magnet system will be adopted for the J-PARC neutrino beam line. GFRPs whose matrices are phenol resin and epoxy resin, and polyimides are used as structural materials and electrical insulation. Radiation resistance of these polymeric materials is very important, because they are exposed to high radiation field. In this work, specimens were irradiated by rays with the maximum dose beyond 10 MGy at liquid nitrogen temperature (77K), and the mechanical properties were investigated. It was verified experimentally that the polymeric materials have sufficient radiation resistance for the using in the J-PARC neutrino beam line.
Makida, Yasuhiro*; Ohata, Hirokatsu*; Okamura, Takahiro*; Ogitsu, Toru*; Nakamoto, Tatsushi*; Kimura, Nobuhiro*; Idesaki, Akira; Gokan, Mayo*; Morishita, Norio
no journal, ,
A Superconducting magnet system will be adopted for the J-PARC neutrino beam line. Since the magnet system will be exposed to high radiation field, the radiation resistance of a cryostat is very important. We have developed radio-proof control valve and relief valve by selection of some parts and separation of the positioner. In this work, the developed valves were worked under the ray irradiation, and it was found that the valves show the radiation resistance above 1 MGy.