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Nagamatsu, Aiko*; Casolino, M.*; Larsson, O.*; Ito, Tsuyoshi*; Yasuda, Nakahiro*; Kitajo, Keiichi*; Shimada, Ken*; Takeda, Kazuo*; Tsuda, Shuichi; Sato, Tatsuhiko
Physics Procedia, 80, p.25 - 35, 2015/12
Times Cited Count：12 Percentile：95.25(Physics, Applied)JAXA has been investigated the effect of the shielding material for dosimeters in the ISS Russian segment under the ALTCRISS project. The PADLES package is a passive dosimeters which usually consists of two types of passive and integrating dosimeters, a CR-39 plastic nuclear track detector and a thermoluminescence dosimeter. In the ALTCRISS experiments, both tissue-equivalent material CR-39 PNTDs and NAN-JAERI were enclosed in the PADLES packages as radiators for CR-39 to precisely measure a personal exposed doses. We compared the doses obtained by PADLESs with or without the PEs, and with or difference of the two tissue-equivalent materials. The results of space radiation measurements of the ALTCRISS project Phase 1 to 4 using the PADLES system will be reported in this time: Phase 1 experiments was from December 2005 to April 2006, Phase 2 was from April to September 2006, phase 3 was from Sep 2006 to April 2007, and Phase 4 was conducted from May to October 2007.
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
Chiba, Satoshi; Ota, Shuya*; Yasuda, Nakahiro*; Sihver, L.*; Kodaira, Satoshi*; Ideguchi, Yusuke*; Hasebe, Nobuyuki*
no journal, ,
no abstracts in English
Ota, Shuya*; Yasuda, Nakahiro*; Sihver, L.*; Kodaira, Satoshi*; Ideguchi, Yusuke*; Hasebe, Nobuyuki*
no journal, ,
Projectile charge-changing cross sections for nuclei in galactic cosmic rays (GCRs) on hydrogen play essentially important roles for the study of origin and source composition of GCRs. Previous experimental and theoretical works done so far made much progress on those cross sections. However, there are still uncertainties in much of the cross section data, and therefore the present knowledge of cross sections has not led to successful determination of the GCR source composition. To improve the uncertainties, a novel measurement system of projectile charge-changing cross section using CR-39 plastic nuclear track detectors with excellent position and nuclear charge resolutions has been developed. We carried out measurements of total and partial charge-changing cross sections for Fe and Mg on 
and 
targets at 0.1 to 1 GeV/n using the method.
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.
Nanda, N.*; Usami, Hiroshi; Morishita, Yuki; Sugita, Takeshi*; Torii, Tatsuo; Yasuda, Nakahiro*
no journal, ,
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
