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Kobayashi, Shingo*; Hasebe, Nobuyuki*; Hosojima, Takehiro*; Ishizaki, Takeshi*; Iwamatsu, Kazuhiro*; Mimura, Mitsuteru*; Miyachi, Takashi*; Miyajima, Mitsuhiro*; Pushkin, K.*; Tezuka, Chikara*; et al.
Japanese Journal of Applied Physics, Part 1, 45(10A), p.7894 - 7900, 2006/10
Times Cited Count：13 Percentile：44.89(Physics, Applied)We have obtained the ratio of transverse diffusion coeffcient to mobility of electrons multiplied by the elementary charge, in Xe and Xe+H
under electric fields at a higher pressure of 1 MPa in comparison with preceding experiments. The result shows that the density effect (non-linear effect) of the ratio in both of pure Xe and Xe+H is 
15% below 1 MPa over the reduced electric field range from 0.08 to 0.6
10
V
cm
. We also found that the diffusion of an electron swarm is suppressed by adding trace of hydrogen to high-pressure xenon gas. Discussion is made of Xe+H gas to a new 
-ray camera. Trace of hydrogen to high-pressure xenon gas. Discussion is made of Xe+H gas to a new -ray camera.
Torii, Tatsuo; Okuyama, Shinichi; Ishizuka, Akihiro
Tokyo Daigaku Uchusen Kenkyujo Heisei-17-Nendo Kyodo Riyo Kenkyu, Kenkyu Seika Hokokushu, P. 129, 2006/00
no abstracts in English
Torii, Tatsuo; Okuyama, Shinichi; Ishizuka, Akihiro; Nozaki, Tatsuo; Nawa, Yasunori*; Sugita, Takeshi*
no journal, ,
ray dose-rate increases associated with winter thunderstorm activities have been observed at the coastal area of the Sea of Japan. The features are clarified from the measured data obtained by environmental radiation monitors. In order to investigate the generation of energetic radiation which originates in thunderstorm electric fields, we have calculated the behavior of secondary cosmic rays (electromagnetic component; muon) in electric fields with Monte Carlo method. In the calculation, the electron and photon fluxes have increased greatly in the region where the field strength exceeds about 280 P(z) kV/m-atm, where P(z) is the atmospheric pressure (atm) at altitude z (m),.and these energy spectra show a large increase in the energy region up to a few tens of MeV. We have also carried out the Monte Carlo calculations of the beta and rays emitted by radon progenies in thunderstorm electric fields. By the calculation for the radon progeny, the electron flux shows notable increases in the strong electric field region, while the photon flux does not fluctuate significantly. As well as the secondary cosmic rays, the radon progeny products form a large part of the energetic charged particles in the atmosphere. Therefore, they can serve as the source of a considerable amount of runaway electrons, through their ionization process with air molecules. These results indicate that the production of energetic electrons plays an important role in the intensive ionization of the air, and as a result a significant growth of electric conductivity in thunderstorm electric fields. These productions may also induce the lightning discharge by these processes.
Ishizuka, Akihiro; Nozaki, Tatsuo; Kokubun, Yuji; Okubo, Koichi; Torii, Tatsuo; Takata, Takushi*; Kume, Kyo*; Hasegawa, Takashi*; Sugita, Takeshi*
no journal, ,
The assessment methods of types and distributions of a radioactivity unexpectedly released to atmosphere from nuclear power plants have been studied with a help of examination of data measured by -ray detectors at several radiation monitoring equipments. The principle was verified with a -ray source in room, and an existing nuclear power station was simulated as an application example.
Takata, Takushi*; Ishizuka, Akihiro; Nozaki, Tatsuo; Kokubun, Yuji; Okubo, Koichi; Torii, Tatsuo; Kume, Kyo*; Otani, Nobuo*; Hasegawa, Takashi*
no journal, ,
The assessment methods of a radioactivity distribution unexpectedly released to atmosphere from nuclear power plants have been studied using a single channel analyzing technique. A combination of this single channel analyzing technique and a detector sensitive to a solid angle of an incident -ray was examined to assess the same purpose.
Na and 
Be depositions in Tsuruga cityYoshida, Keisuke; Kato, Shingo; Inoue, Mutsuo*; Ishizuka, Akihiro; Okuyama, Shinichi
no journal, ,
Na is observed for environmental monitoring of Monju fast breeder reactor because Monju reactor contains Na in primary coolant. But Na is produced in upper atmosphere, therefore, Na is detected in assembled deposition sample. To increase accuracy of environmental monitoring, it is necessary to understand transport and supply process of Na and Be depositions from high latitude region where a lot of Na is produced. We collect deposition samples at Tsuruga city to measure Na and collect Be deposition data in 5 sites in Fukui prefecture and Ishikawa prefecture. Because Na and Be shows good correlation, Na have same behavior with Be. Be deposition is maximum at Kanazawa city and minimum at Shika town, but Be deposition is maximum in Winter season at all sites. Be deposition and precipitation shows correlation. From the above, Winter monsoon transport Be and Na from high latitude region and precipitation provide these nuclides to ground surface at Tsuruga city. The deference of Be deposition in Winter season is likely owing to height of mountain and distance of sampling sites.
Kato, Shingo; Ishizuka, Akihiro; Okuyama, Shinichi; Nozaki, Tatsuo; Hayashi, Gaku*; Yasuda, Nakahiro*; Torii, Tatsuo*; Ando, Takasuke*
no journal, ,
no abstracts in English
Hayashi, Gaku*; Torii, Tatsuo*; Ishizuka, Akihiro; Okuyama, Shinichi; Kato, Shingo; Nozaki, Tatsuo; Yasuda, Nakahiro*
no journal, ,
no abstracts in English
