RADIOISOTOPES
Online ISSN : 1884-4111
Print ISSN : 0033-8303
ISSN-L : 0033-8303
Volume 61 , Issue 6
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  • Shunji YUNOKI, Masaaki SAITO, Yoshiyasu NAGAKAWA
    2012 Volume 61 Issue 6 Pages 307-313
    Published: 2012
    Released: June 29, 2012
    JOURNALS OPEN ACCESS
    The influence of atmospheric 14CO2 was evaluated on the determination of biogenic carbon ratios in industrial flue gases using accelerated mass spectrometry(AMS). Bioethanol, n-hexane, and their mixtures were combusted with a four-stroke engine, and 14CO2 in exhaust gases was analyzed by AMS. The experimental biogenic carbon ratio determined by ASTM D6866 method was 1.2 times higher than the theoretical value of mixed fuel containing 3.18% biogenic carbons. In general, the influence of atmospheric 14CO2 taken in combustion gases is neglected. It seems that the error cannot be neglected under international trading of emission allowances, where a large amount of carbons in the fuel were evaluated. The experimental value became to be the theoretical value by subtracting the amount of atmospheric 14C from that of the samples. As the contents of biofuel increased, the experimental biogenic carbon ratios reached the theoretical values and the influence of atmospheric 14CO2 decreased. We recommend that the influence of atmospheric 14CO2 should be corrected when fuel samples contain low amounts of 14C.
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  • Kaoru SATO, Kentaro MANABE, Akira ENDO
    2012 Volume 61 Issue 6 Pages 315-320
    Published: 2012
    Released: June 29, 2012
    JOURNALS OPEN ACCESS
    Average adult Japanese male(JM-103) and female (JF-103) voxel (volume pixel) phantoms newly constructed at the Japan Atomic Energy Agency (JAEA) have average characteristics of body sizes and organ masses in adult Japanese. In JM-103 and JF-103, several organs and tissues were newly modeled for dose assessments based on tissue weighting factors of the 2007 Recommendations of the International Commission on Radiological Protection(ICRP). In this study, SAFs for thyroid, stomach, lungs and lymphatic nodes of JM-103 and JF-103 phantoms were calculated, and were compared with those of other adult Japanese phantoms based on individual medical images. In most cases, differences in SAFs between JM-103, JF-103 and other phantoms were about several tens percent, and was mainly attributed to mass differences of organs, tissues and contents. Therefore, it was concluded that SAFs of JM-103 and JF-103 represent those of average adult Japanese and that the two phantoms are applied to dose assessment for average adult Japanese on the basis of the 2007 Recommendations.
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Letters
Review Article
Serial Lecture
New Neutron Imaging Using Pulsed Sources
  • Yujiro IKEDA
    2012 Volume 61 Issue 6 Pages 343-351
    Published: 2012
    Released: June 29, 2012
    JOURNALS OPEN ACCESS
    Giving an overview of the high intensity proton accelerator facility, J-PARC, which has started its user program since December 2008, the neutron source as the major user facility is described. Stressing an advancement of J-PARC pulse neutron source, in particular, important characteristic neutron performance and present situation in implementation of neutron instruments, which maximizes the neutron source performance, are addressed along with recent prominent scientific output. User operation condition in terms of proton beam power just before the devastating earthquake events on March 11, 2011, is touched upon briefly as an record. Showing damage to J-PARC facility from the earthquake, current recovering work as well as the operation schedule is described. In addition to last two years’ experience in user program, a plan to reach the 1MW power of the primary goal of J-PARC is shown.
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