RADIOISOTOPES
Online ISSN : 1884-4111
Print ISSN : 0033-8303
ISSN-L : 0033-8303
Volume 27 , Issue 2
Showing 1-12 articles out of 12 articles from the selected issue
  • Hiroshi MIYAHARA, Tamaki WATANABE
    1978 Volume 27 Issue 2 Pages 69-73
    Published: February 15, 1978
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    An extension of 4πe·X-γ coincidence technique is described to measure the absolute disintegration rate of85Sr.This nuclide shows electron capture-gamma decay, and 514 keV level of85Rb is a meta-stable state with half life of 0.958μsee. Therefore, the conventional 4πe⋅X-γ coincidence technique with about 1μsec of resolution time can not be applied to this nuclide. To measure the absolute disintegration rate of this, the delayed 4πe⋅X-γ coincidence technique with two different resolution times has been used. The disintegration rate was determined from four counting rates of electron-X ray, gamma ray and two coincidences, and the true disintegration rate could be obtained by extra poration of the electron-X ray detection efficiency to 1. Two resolution times appearing in the calculation formulas were determined from the chance coincidence between electron-X ray and delayed gamma ray signals. When the coincidence countings with three different erent resolution time were carried out by one coincidence circuit, the results calculated from all combinations did not agree each other. However, when the two coincidence circuits of the same type were used to fix the resolution time, a good coincidence absorption function was obtained and the disintegration rate was determined with accuracy of±0.5%. To evaluate the validity of the results the disintegration rates were measured by twoNaI (Tl) scintillation detectors whose gamma-ray detection efficiency was previously determined and both results were agreed within accuracy of±0.5%. This method can be applied with nearly same accuracy for the beta-gamma decay nuclide possessing a meta-stable state of the half life below about 10 μsec.
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  • Makoto TAKIUE, Hiroaki ISHIKAWA
    1978 Volume 27 Issue 2 Pages 74-79
    Published: February 15, 1978
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    The quenching effect for halogenated benzenes, methanes and ethanes have been investigated. The halogen quenching was accurately measured using the internal conversion electrons emitted from113Sn-113mIn.
    From the quenching constants determined by the Stern-Volmer plots with respect to various halogen quenchers, the following results have been obtained. (1) The quenching constants increase with the number of halogen substituents, so as linearly in halogenated benzenes and exponentially in halogenated methanes and ethanes. Even the isomers of halogenides have different quenching constants. (2) There is a linearity between logarithm of the quenching constant and a polarographic half wave reduction potential. (3) Electron excitation provides larger quenching constants than UV excitation for halogenated methanes.
    Based on these results, the mechanism of halogen quenching have been discussed in connection with the exciplex formation.
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  • Kunio TAKEI, Hiroshi KICHIKAWA, Hitoshi HAGIWARA
    1978 Volume 27 Issue 2 Pages 80-84
    Published: February 15, 1978
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    In 1938, S. V. Raghava Rao reported that a crystal of HgXSCN (X=halogen) has photropic properties and in 1955, the author reported the mechanism of the phototropy is identical with that ofHgI2·2HgS.However, a behavior of S, I and C atoms in the crystals irradiated by sunlight was not known. Purpose of this paper is to clarify the behavior of these atoms by using radioactive tracer technique. The results obtained show that when electrons belonging to S2-or I-ions absorb photons and are excited to upper state, these electrons leave behind neutral S or I atoms, which diffuse thermally toward the crystal surface and escape into atmosphere.14C atoms do not escape. S atoms are more sensitive to light than I or C atoms.
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  • Tatsunosuke HIRAKI, Atsushi ANDO, Hirofumi MORI, Itsuko ANDO, Koh SAKA ...
    1978 Volume 27 Issue 2 Pages 85-89
    Published: February 15, 1978
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    For the purpose of calculating absorbed dose to humans from167Tm-citrate, the wholebody retention studies using 5 rats were carried out. Up to 40 days following intravenous injection of 167Tm-citrate, the whole-body counts were monitored with a animal counter.
    The whole-body retention curve was obtained with three exponentaial components. Namely, the 26% of the injected187Tm-citrate had a biological half-time of 3.4 hours, 12.5% had a biological half-time of 99 hours and 61.5% had a biological half-time of 106 days. These results indicate, that three components consist of the rapid clearance from the kidneys, the retention in the liver and other soft tissues with relatively long half-time and the retention in the bones with long half-time.
    Based on these biological data and the MIRD Committee method, the average dose estimates to the bone and whole-body from intravenous administration of 1 mCi167Tm-citrate were 7.08 rads and 1.28 rads, respectively.
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  • Kunio CHAYA, Norikatsu HAMAMURA
    1978 Volume 27 Issue 2 Pages 90-93
    Published: February 15, 1978
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • Isao UCHIDA, Teizo TOMARU, Toraji IRIFUNE, Seiji TAKAHASHI, Etsuji NOM ...
    1978 Volume 27 Issue 2 Pages 94-97
    Published: February 15, 1978
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • Noriyuki MIYAZAKI, Hisanao OHKURA
    1978 Volume 27 Issue 2 Pages 98-100
    Published: February 15, 1978
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • Yasuo ENDO
    1978 Volume 27 Issue 2 Pages 101-104
    Published: February 15, 1978
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • Katsuya NAGASE, Yoshinari ARAKAWA, Masayoshi TANAKA, Susumu IIDA, Kiyo ...
    1978 Volume 27 Issue 2 Pages 105-107
    Published: February 15, 1978
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • Makoto KONDO, Hidekazu MASAKI, Yaeko TAKAGI, Atsushi KUBO, Shozo HASHI ...
    1978 Volume 27 Issue 2 Pages 108-111
    Published: February 15, 1978
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • Minoru IRIE, Hiroshi TAKINO
    1978 Volume 27 Issue 2 Pages 112-121
    Published: February 15, 1978
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • 1978 Volume 27 Issue 2 Pages A1795-A1692
    Published: February 15, 1978
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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