Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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：93.95(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.
Yoshida, Kensuke*; Fujioka, Shinsuke*; Higashiguchi, Takeshi*; Ugomori, Teruyuki*; Tanaka, Nozomi*; Kawasaki, Masato*; Suzuki, Yuhei*; Suzuki, Chihiro*; Tomita, Kentaro*; Hirose, Ryoichi*; et al.
Applied Physics Letters, 106(12), p.121109_1 - 121109_5, 2015/03
Times Cited Count：10 Percentile：38.07(Physics, Applied)Kai, Takeshi; Yokoya, Akinari; Ukai, Masatoshi*; Fujii, Kentaro; Higuchi, Mariko; Watanabe, Ritsuko
Radiation Physics and Chemistry, 102, p.16 - 22, 2014/09
Times Cited Count：24 Percentile：86.35(Chemistry, Physical)no abstracts in English
Yoshida, Kensuke*; Fujioka, Shinsuke*; Higashiguchi, Takeshi*; Ugomori, Teruyuki*; Tanaka, Nozomi*; Ohashi, Hayato*; Kawasaki, Masato*; Suzuki, Yuhei*; Suzuki, Chihiro*; Tomita, Kentaro*; et al.
Applied Physics Express, 7(8), p.086202_1 - 086202_4, 2014/08
Times Cited Count：29 Percentile：73.72(Physics, Applied)We demonstrate high conversion efficiency for extreme ultraviolet (EUV) emission at 6.5-6.7 nm from multiple laser beam-produced one-dimensional spherical plasmas. Multiply charged-state ions produce strong resonance emission lines, which combine to yield intense unresolved transition arrays in Gd, Tb, and Mo. The maximum in-band EUV conversion efficiency was observed to be 0.8%, which is one of the highest values ever reported due to the reduction of plasma expansion loss.
Kai, Takeshi; Higuchi, Mariko; Fujii, Kentaro; Watanabe, Ritsuko; Yokoya, Akinari
International Journal of Radiation Biology, 88(12), p.928 - 932, 2012/12
Times Cited Count：1 Percentile：12.53(Biology)Sugaya, Atsushi; Horiguchi, Kenichi; Tanaka, Kenji; Kobayashi, Kentaro
Materials Research Society Symposium Proceedings, Vol.1107, p.173 - 179, 2008/00
In Nuclear Fuel Reprocessing Plant, it is necessary to dispose of a large amount of low level radioactive effluent containing nitrate as a major ingredient, safely and economically. Therefore, engineering developments concerning a cement based encapsulation process have been carried out in JAEA. From the viewpoint of disposal cost decrease, a low level radioactive effluent is passed through the nuclide separation process before cementation to concentrate the radioactivity into the minimum volume for conditioning and disposal. Two kinds of effluents are generated as a result of the nuclide separation; Non-radioactive simulants were prepared for each of these waste streams, and used in encapsulation trials to investigate a special slag cement, on a beaker scale and at full scale (200-litres). The results have confirmed that the nitrate effluent, evaporated up to a predetermined density, can be successfully encapsulated at a salt filling rate of 50wt%, to produce a wasteform which satisfies the required conditions. In the slurry effluent, the strength of the product decreased when carbonate concentration was high. However, it was confirmed that the product made at salt filling rate 50wt% satisfied the required conditions, if the carbonate concentration in the effluent was decreased to 10 g/L or less.
Sugiyama, Kenichiro*; Iguchi, Kentaro*
JAERI-Tech 2002-010, 67 Pages, 2002/03
no abstracts in English
Sugaya, Atsushi; Horiguchi, Kenichi; Tanaka, Kenji; Kobayashi, Kentaro
no journal, ,
In Nuclear Fuel Reprocessing Plant, it is necessary to dispose of a large amount of low level radioactive effluent containing nitrate as a major ingredient, safely and economically. Therefore, engineering developments concerning a cement based encapsulation process have been carried out in JAEA. From the viewpoint of disposal cost decrease, a low level radioactive effluent is passed through the nuclide separation process before cementation to concentrate the radioactivity into the minimum volume for conditioning and disposal. Two kinds of effluents are generated as a result of the nuclide separation; a nitrate effluent of which the principal ingredient is nitrate with a comparatively low radiation level, and a slurry effluent including several kinds of salts with a comparatively high radiation level. Non-radioactive simulants were prepared for each of these waste streams, and used in encapsulation trials to investigate a special slag cement, on a beaker scale and at full scale (200-litres). The results have confirmed that the nitrate effluent, evaporated up to a predetermined density, can be successfully encapsulated at a salt filling rate of 50wt%, to produce a wasteform which satisfies the required conditions. In the slurry effluent, the strength of the product decreased when carbonate concentration was high. However, it was confirmed that the product made at salt filling rate 50wt% satisfied the required conditions, if the carbonate concentration in the effluent was decreased to 10g/L or less.
Takano, Masato; Horiguchi, Kenichi; Tanaka, Kenji; Kobayashi, Kentaro
no journal, ,
no abstracts in English
Horiguchi, Kenichi; Sugaya, Atsushi; Tanaka, Kenji; Kobayashi, Kentaro; Sasaki, Tadashi*
no journal, ,
no abstracts in English
Horiguchi, Kenichi; Sugaya, Atsushi; Tanaka, Kenji; Kobayashi, Kentaro; Sasaki, Tadashi*
no journal, ,
In Nuclear Fuel Reprocessing Plant, it is necessary to dispose of a large amount of low level radioactive effluent containing nitrate as a major ingredient, safely and economically. Therefore, engineering developments concerning a cement based encapsulation process have been carried out in JAEA. From the view point of disposal cost decrease, a low level radioactive effluent is passed through the nuclide separation process before cementation to concentrate the radioactivity into the minimum volume for conditioning and disposal. Two kinds of effluents are generated as a result of the nuclide separation; A nitrate effluent of which the principal ingredient is nitrate with a comparatively low radiation level, and; A slurry effluent including several kinds of salts with a comparatively high radiation level. Non-radioactive stimulants were prepared for each of these waste streams, and used in encapsulation trials to investigate special slag cement, on a beaker scale and full scale(200-litres). Furthermore, JAEA has carried out hazardous material judgment for cement products and leaching test of the cement products which encapsulated actual effluent. I will report that result of there development trials.
Horiguchi, Kenichi; Sugaya, Atsushi; Tanaka, Kenji; Kobayashi, Kentaro; Sasaki, Tadashi*
no journal, ,
In Nuclear Fuel Reprocessing Plant, it is necessary to dispose of a large amount of low level radioactive effluent safely and economically. In JAEA engineering developments concerning a cement solidification process have been carried out. The phosphate effluent occurring from solvent waste treatment facility is based on sodium dihydrogen phosphate. The acidity of this effluent (pH 4) requires a pre-treatment process before cement solidification. Phosphate effluent interfere with cementing reactions by retard of reaction rate and loss of strength, because it is combined with calcium that is element of cement material. It reports on the result of Non-radioactive simulant was prepared for the phosphate effluent, and used in cementation trials to investigate a special slag cement, on a beaker scale and at full scale (200-litres).
Sugaya, Atsushi; Horiguchi, Kenichi; Tanaka, Kenji; Kobayashi, Kentaro
no journal, ,
Tokai Reprocessing Center is developing a cement based encapsulation method to immobilize low level radioactive effluent. Phosphate effluent arising from Solvent Waste Treatment Facility interfere with cementing reactions by retard of reaction rate and loss of strength, because it is combined with calcium that is element of cement material. It reports on the result of pretreatment trials at small scale executed to ease adverse effect of phosphate.
Kai, Takeshi; Higuchi, Mariko; Fujii, Kentaro; Watanabe, Ritsuko; Yokoya, Akinari
no journal, ,
no abstracts in English
Kai, Takeshi; Yokoya, Akinari; Ukai, Masatoshi*; Fujii, Kentaro; Higuchi, Mariko; Watanabe, Ritsuko
no journal, ,
no abstracts in English
Kai, Takeshi; Yokoya, Akinari; Ukai, Masatoshi*; Fujii, Kentaro; Higuchi, Mariko; Watanabe, Ritsuko
no journal, ,
no abstracts in English
Sakai, Yosuke*; Minato, Haruna*; Ishihara, Kohei*; Tomita, Hideki*; Kawarabayashi, Jun*; Iguchi, Tetsuo*; Naka, Tatsuhiro*; Asada, Takashi*; Morishima, Kunihiro*; Nakano, Toshiyuki*; et al.
no journal, ,
In order to measure a neutron-spectrum under high 
ray environment, a new nuclear emulsion and its data-processing method are developed. In fast neutron measurement using the nuclear emulsion which can record the three-dimensional track of a charged particle, incidence neutron energy spectrum can be obtained by analyzing the track of the recoil proton generated by the elastic scattering of a neutron. The high-speed automatic analytic method of the recoil proton track in a nuclear plate is developed. It checked that the recoil proton track length distribution obtained by viewing and automatic analysis was in agreement with a model calculation result about by the basic experiment using 14 MeV neutron.
Sakai, Yosuke*; Minato, Haruna*; Ishihara, Kohei*; Tomita, Hideki*; Kawarabayashi, Jun*; Iguchi, Tetsuo*; Naka, Tatsuhiro*; Asada, Takashi*; Morishima, Kunihiro*; Nakano, Toshiyuki*; et al.
no journal, ,
In order to measure a neutron-spectrum under high ray environment, a new nuclear emulsion and its data-processing method are developed. In fast neutron measurement using the nuclear emulsion which can record the three-dimensional track of a charged particle, incidence neutron energy spectrum can be obtained by analyzing the track of the recoil proton generated by the elastic scattering of a neutron. The high-speed automatic analytic method of the recoil proton track in a nuclear plate is developed. It checked that the recoil proton track length distribution obtained by viewing and automatic analysis was in agreement with a model calculation result about by the basic experiment using 14 MeV neutron.
Kai, Takeshi; Yokoya, Akinari; Ukai, Masatoshi*; Fujii, Kentaro; Higuchi, Mariko; Watanabe, Ritsuko
no journal, ,
no abstracts in English
Nishiuchi, Mamiko; Sakaki, Hironao; Pirozhkov, A. S.; Sagisaka, Akito; Kon, Akira; Fukuda, Yuji; Kiriyama, Hiromitsu; Dover, N.*; Sekiguchi, Kentaro; Ogura, Koichi; et al.
no journal, ,
Petawatt class laser systems are in nowadays almost ready to work in all over the world. High energy particles accelerated by the interaction between laser pulses from high intensity laser system and the material shows interesting and particular parameters. Therefore those attract many fields of applications. High contrast and ultra high intensity laser system J-KAREN at KPSI is now under upgrading for achieving highest energy ion beams. No laser system with pulse duration less than 100 fs has demonstrated 100 MeV class proton acceleration in the world. To achieve high energy ions requires higher intensity laser on the target. We report on this presentation the status of the upgrading and the experimental results obtained at the first light experiment.
