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Wada, Seiichi; Natsuhori, Masahiro*; Ito, Nobuhiko*; Funayama, Tomoo; Kobayashi, Yasuhiko
Nuclear Instruments and Methods in Physics Research B, 206, p.553 - 556, 2003/05
Times Cited Count：3 Percentile：27.69(Instruments & Instrumentation)Determining the biological effects of a very low number of charged particles crossing the cell nucleus is interest for estimating the risk due to environmental exposure to charged particles. Especially it is necessary to detect the radiation damage induced by a precise number of charged particles in the individual cells. To compare the number of ions traversing the cell and the DNA damage produced by the hit ions, we applied comet assay. Cells attached on the ion track detector CR-39 were irradiated with 17.3 MeV/u 12C, 15.7 MeV/u, 10.4 MeV/u 20Ne and 6.9 MeV/u 40Ar ion beams at TIARA, JAERI-Takasaki. After irradiation, CR-39 was covered with 1 % agarose. After electrophoresis the CR-39 was taken off from the slide glass. The agarose gel on the CR-39 was stained with ethidium bromide and the opposite side of the CR-39 was etched with KOH-ethanol solution at 37 
. We observed that the ion particles with higher LET value induced the heavier DNA damage, even by the same number of ion-hits within the irradiated cells.
Ogura, K.*; Asano, Masaharu; Yasuda, Nakahiro*; Yoshida, Masaru
Nuclear Instruments and Methods in Physics Research B, 185(1-4), p.222 - 227, 2001/12
Times Cited Count：32 Percentile：89(Instruments & Instrumentation)no abstracts in English
Oda, Keiji*; Ichijo, H.*; Miyawaki, Nobumasa*; Yamauchi, Tomoya*; Nakane, Yoshihiro
Radiation Measurements, 34(1-6), p.171 - 175, 2001/06
Times Cited Count：7 Percentile：48.68(Nuclear Science & Technology)no abstracts in English
Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru
JAERI-Review 99-025, TIARA Annual Report 1998, p.87 - 88, 1999/10
no abstracts in English
Kamiya, Tomihiro; Sakai, Takuro; *; *; Hirao, Toshio
Nuclear Instruments and Methods in Physics Research B, 158(1-4), p.255 - 259, 1999/00
Times Cited Count：6 Percentile：46.78(Instruments & Instrumentation)no abstracts in English
Kamiya, Tomihiro; Sakai, Takuro; *; *; Hirao, Toshio
F-113-'98/NIES, p.60 - 63, 1998/00
no abstracts in English
*; Hirao, Toshio; Nashiyama, Isamu; Sakai, Takuro; Kamiya, Tomihiro; *; Ishii, Keizo*
Radiation Physics and Chemistry, 53(5), p.461 - 467, 1998/00
Times Cited Count：1 Percentile：15.03(Chemistry, Physical)no abstracts in English
Kamiya, Tomihiro; ; *; Suda, Tamotsu*; Hirao, Toshio
Nuclear Instruments and Methods in Physics Research B, 130(1-4), p.285 - 288, 1997/00
Times Cited Count：12 Percentile：67.93(Instruments & Instrumentation)no abstracts in English
Asano, Masaharu; Tamada, Masao; Yoshida, Masaru; Omichi, Hideki; Katakai, Ryoichi*; Vetter, J.*; Spohr, R.*
GSI 94-1, P. 204, 1994/03
no abstracts in English
Tamada, Masao; Yoshida, Masaru; Asano, Masaharu; Omichi, Hideki; Katakai, Ryoichi*; Trautmann, C.*; Vetter, J.*; Spohr, R.*
Nucl. Tracks Radiat. Meas., 20(4), p.543 - 547, 1992/00
no abstracts in English
Kaetsu, Isao;
J.Appl.Polym.Sci., 24(1), p.235 - 247, 1979/00
Times Cited Count：8no abstracts in English
; *; Kaetsu, Isao
J.Appl.Polym.Sci., 22(1), p.27 - 42, 1978/01
Times Cited Count：3no abstracts in English
Kodaira, Satoshi*; Yasuda, Nakahiro*; Hosogane, Tatsuya; Ishikawa, Fumitaka; Kageyama, Tomio; Sato, Mitsuhiro
no journal, ,
The plutonium-thermal use is expected as one of the approach for reuse of spent uranium fuel in nuclear power generation. On the other hand, many kinds of nuclides including Pu with extremely long half-lives are generated in the used fuels, which would be problems for storage and control of radioactive waste. The MOX (Mixed Oxide) consisting of plutonium dioxide enriched with 4-9% Pu and uranium oxide from spent uranium fuel would allow to reduce half-lives of radioactive waste significantly through the nuclear fission. The quality of MOX pellet depends on the homogeneous dispersion of Pu. The region of highly concentrated Pu is sometimes observed as "Pu spot" in the pellet, which has the potential of anomalous combustion localized at that region. The detection of Pu spot and evaluation of its size and concentration are one of the important quality assurance of MOX pellet for the safety use in the nuclear power plant. We have applied CR-39 plastic nuclear track detectors for the measurement of Pu spot inside MOX pellet. CR-39 can image a cross-section of MOX pellet by recording 
-particle tracks from Pu in the pellet, like autoradiography. The Pu spot is visibly imaged as a "black spot" due to the dense tracks compared to homogeneously dispersed region. Conventionally, the Pu spot measurement has been carried out with manual scanning, which takes much longer times and huge amount of human work. We have developed the automatic detection and measurement system of Pu spot recorded on CR-39 by the image processing with filtering and clustering algorithms. The detection efficiency with CR-39 is achieved to be almost 100% compared with conventional manual scanning result. It provides more information about the number, size and position of Pu spot.
Kanasaki, Masato; Jinno, Satoshi*; Sakaki, Hironao; Faenov, A. Ya.*; Pikuz, T. A.*; Nishiuchi, Mamiko; Kiriyama, Hiromitsu; Kando, Masaki; Kondo, Kiminori; Matsui, Ryutaro; et al.
no journal, ,
In the laser-driven ion acceleration using cluster-gas target, the acceleration mechanism consists of different processes such as, (a) acceleration of ions due to Coulomb explosion of individual clusters, (b) compression and acceleration of background gas ions due to the Coulomb explosion of clusters, (c) magnetic vortex generation and associated pinching near the rear surface, and (d) sheath acceleration at the interface between the medium and vacuum. To reveal the synergetic interplay between the processes (a) and (b), we have conducted ion acceleration experiments using CO
clusters embedded in background H gas with the J-KAREN laser. By a careful analysis of CR-39, we have found that the maximum energies of protons and carbon ions are 1.5 MeV and 1.1 MeV/u, respectively. Based on the experimental results, the acceleration mechanism of background gas ions induced by Coulomb explosion of clusters can be discussed with the help from numerical simulations.
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
Hashimoto, Suki*; Sakuma, Shuhei; Hosomi, Kenji; Watanabe, Yuki; Unno, Motoyoshi; Takashima, Hideki
no journal, ,
The standards for passive neutron personal dosimeters do not cover high-dose exposures such as criticality accidents, so the upper limit of the dose for personal neutron dosimeters is 20 mSv. On the other hand, the upper limit of dose during emergency work was raised to 250 mSv during the TEPCO Fukushima Daiichi Nuclear Power Plant accident caused by the Great East Japan Earthquake, so it is desirable that personal neutron dosimeters be able to support the upper limit of 250 mSv. In this study, we confirmed the availability of neutron dose evaluation of 250 mSv by irradiating neutron personal dosimeter using PADC detector called CR-39 with up to 300 mSv.
