RADIOISOTOPES
Online ISSN : 1884-4111
Print ISSN : 0033-8303
ISSN-L : 0033-8303
Volume 13 , Issue 1
Showing 1-13 articles out of 13 articles from the selected issue
  • Masatoshi KOBAYASHI, Sho MAEDA, Teruko SAWAI, Sumiko NAGATSUKA
    1964 Volume 13 Issue 1 Pages 1-6
    Published: January 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    The activation analysis of minor quantity of oxygen has much interest because its behaviour is very important for almost materials, such as metals, alloys and chemicals.
    Various kinds of nuclear reactions have been tried by many workers to establish the practical method of the analysis of oxygen.
    In the present work, we tried to know about the activation analysis of oxygen in pure aluminium ingot or in the oxide film deposited by means of the anodic oxidation, so as to establish the practical application of this nuclear reaction using a linear accelerator.
    After irradiation for two minutes, the oxygen concentrations in samples were determined by the measurement of annihilation peak at 0.51 MeV with a γ-ray spectrometer.
    Unless there is an interfering nuclear reaction we can determine oxygen less than 1 ppm by using the measurement of the gross or total activity, however, it was possible for only 20 ppm in our case.
    We tried next to know about the relative activities of various elements at some fixed bombarding energies by using a betatron of 31 MeV for medical use.
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  • Nobuhiko ISHIBASHI, Satsuo KAMATA, Kazuo ISHIDA, Akira KATASE
    1964 Volume 13 Issue 1 Pages 7-12
    Published: January 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    Activation analysis with 14 MeV neutrons was investigated for determination of fluors e contents in its compounds and bromine contents in sodium chloride. Fast neutrons were produced by the D-T reaction with the Cockcroft-Walton accelerator. Teflon (and Tepcn FEP), sodium fluoride, calcium fluoride and sodium fluorosilicate were used as fluorine samples to be analysed, while mixtures of sodium bromide and sodium chloride as bromine samptss. These samples were irradiated for 120 minutes (fluorine sample) or 6 minutes (bromine sampts) on the rotating disk of 50-70 rpm. Neutron fluxes were usually about 106n/cm2⋅ sec at sampe positions.
    Observations of gamma rays with the 128 channel spectrometer (or single channel spectre meter) and decay curves of 0.51 MeV photopeak showed that gamma rays from fluorzns samples were only one of 0.51 MeV emitted from 18F produced by (n, 2n) reaction with 19F, A large photopeak at 0.51 MeV and a small one at 0.62 MeV were observed for pure sodium bromide. The former peak was presumably emitted from 78Br produced by (n, 2n) reaction with 79Br. When a large amout of sodium chloride was mixed with sodium bromide, decay curve of the 0.51 MeV peak tends to deviated from linear line on the usual semi-logarithmic plots. Deviation may be due to gamma rays from 34mCl. Component of this gamma rays was subtracted from the total counts by using the activity of irradiated pure sodium chloride for the analytical calculation.
    Flourine and bromine contents calculated from the radioactivities of 0.51 MeV photopeak sufficiently agreed with values from chemical analysis. Bromine in sodium chloride can be analysed to content of 0.8% with a considerable good accuracy.
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  • Tsunenobu SHIGEMATSU, Masayuki TABUSHI, Shiro GODA, Kenzo TAMAKI, Yasu ...
    1964 Volume 13 Issue 1 Pages 13-19
    Published: January 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    Radioactivation analysis of manganese was studied with a low-level neutron source, (1c) Pu+Be, and the procedure designed was applied to the nondestructive analysis of the element in some mineral samples.
    Paraffin was used as moderator, and the distribution of thermal neutron was measured by using In foil, MnO2 and Au foil. The maximum thermal neutron flux of 3×103n/cm2⋅sec. was obtained with 1-2.1 em thick paraffin.
    The self-shielding effect and self-absorption effect were also studied; the both effects were observed when the amounts of sample exceeded 250 mg.
    Two hundred and fifty milligrams of powdered sample (Ca. 200 mesh) was irradiated for 17 hours at the distance of 2.5 cm from the neutron source, and after cooling for 10 min, activity was measured with G-M counter.
    The decay curve and the gamma scintillation spectrum indicated that the activity obtained was attributed to the decay of 56Mn. The constituents of minerals such as O, Na, Mg, Al, Si, Ca, Fe etc., did not give any effect, when manganese content was more than 2 %. Manganese in minerals can be determined within the relative error of 5%.
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  • Masatoshi KOBAYASHI, Teruko SAWAI
    1964 Volume 13 Issue 1 Pages 20-25
    Published: January 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    The additions of a small quantity of uranium to steel has been proposed so as to improve some mechanical properties.
    This paper describes the activation analysis of the alloyed uranium component in steel. The samples of the commercial carbon steels containing 0.1% and 0.5% uranium were irradiated for a few minutes in a flux of 1011n/cm2⋅sec, allowed to stand for about 48 hrs, then their radioactivities were measured directry without any chemical separation. The radio-nuclide used is239Np (half-life 2.33 day) which allows the measurement of a photoelectric peak at 0.105 MeV with a 13/4 in φ×2 in NaI (Tl) crystal and 512-channel's γ-ray spectrometer. The results were in good agreement with the colorimetric analysis. We applied this method to the study of the segregation of uranium in two ingots.
    This method of activation analysis for uranium in steel offers the advantages of rapidity and simplicity in operation and it permits the determination of the uranium content from 1% to 0.0001 %.
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  • Masatoshi KOBAYASHI, Sumiko NAGATSUKA, Teruko SAWAI
    1964 Volume 13 Issue 1 Pages 26-31
    Published: January 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    A simple separation scheme was examined for the systematic determination of the radioactive nuclides which were produced comparatively easily from the impurities contained in aluminium of high purity.
    These radionuclides were classified into two groups according to their half-lives. That is to say, the impurities such as copper, antimony, arsenic and gallium which give rise to the radioactivities with comparatively short half-lives are separated by precipitation method and the impurities such as scandium, iron, zinc and cadmium that give rise to long-lived gamma activities are separated by anion exchange method. The separated fractions are then analyzed by γ-ray spectrometry. This simple separation scheme enables to determine copper (2×10-5g), antimony (5×10-7g), arsenic (8×10-8g), gallium (3×10-7g), scandium (6×10-8g), iron (4×10-5g), zinc (9×10-6g) and cadmium (7×10-8g) .
    By this scheme the time needed in the systematic analysis was about five hours respectivly on the precipitation method and on the anion exchange method.
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  • Yoshio YAMADA
    1964 Volume 13 Issue 1 Pages 32-38
    Published: January 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    Radioactivation analysis is very useful for the determination of micronutrient elements in soil. The details of the methods are described for Ni, Cu, Zn, Mo and Co in soil. Soil samples and standard samples, which contained known amounts of the elements, were activated simultaneously for 14 hours in the pile (1.5×1012 neutrons per sq. cm per second) and sys tematie radiochemical separation of the individual elements were followed using carriers.
    Finally, these elements were precipitated as Ni-dimethylglyoxime, Cu-thiocyanate, Zn-quinaldate, Mo-hydroxyquinolate and potassium cobaltinitrite. Radiochemical purity of each compound was confirmed by plotting decay curve and gamma spectrometry. The radioactivities due to these elements from the soil samples and standard samples were compared after correction for chemical yields, self-absorption, radioactive decay and paralysis time. The quantities of these elements were calculated by beta counts and gamma counts, respectively. The results for the soils treated or nontreated the farmyard manure for many years showed that the farmyard manure had small increasing effects on the contents of the micronutrient elements in soil.
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  • Masao SHIBUYA
    1964 Volume 13 Issue 1 Pages 39-45
    Published: January 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    By the use of the techniques of neutron activation analysis the following methodological studies were made; (1) non-destructive systematic activation analysis of Mn, Na, Cu, Zn and Sb in rice plants, and (2) the determination of individual rare earth element in rice plants and soils by activation-focusing-chromatography.
    In the first study, 100 mg of rice plant materials were used for analysis, and these samples were transferred from nuclear reactor (Max. thermal neutron flux is 5×1011n/cm2⋅ sec) to a cooling system. The radioactivity was measured by a 256-channel pulse-height analyser.
    According to the differences of neutron cross section, the decay constant and the content of the element in question, the time reqiured for neutron irradiation and cooling time were selected.
    No chemical treatment was included in this process. Samples are in no way changed after determination of one element. Consequently, starting with short-lived nuclides, many elements were analysed successively.
    In the second study, a neutron-irradiated sample was extracted by the appropriate reagent in aqueous solution, and the solution was painted on the chromatographic paper and subjected to separation.
    The perfect separation of individual rare earth element was possible within 10 minutes under the suitable conditions as follows: Complexing reagent was 0.5 M citric acid, pH gradient of both solutions between anode and cathode was 1.5 (HCl) -4.35 (citric acid), the applied voltage was 900 V (D.C.) .
    After treatment of separation, the autoradiographic technique was used to decide the position of separated lines.
    The identification and determination were carried out by measuring 7-activity and spectra of their separated lines cut from the strip.
    Resulting data, La, Sm and Eu were found in rice plants and rice soils, but Tb, Tm and Yb were found to be present in only trace amounts.
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  • [in Japanese], [in Japanese]
    1964 Volume 13 Issue 1 Pages 46-49
    Published: January 15, 1964
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • [in Japanese]
    1964 Volume 13 Issue 1 Pages 50-52
    Published: January 15, 1964
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • [in Japanese], [in Japanese]
    1964 Volume 13 Issue 1 Pages 53-79
    Published: January 15, 1964
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • [in Japanese]
    1964 Volume 13 Issue 1 Pages 80-91
    Published: January 15, 1964
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • [in Japanese]
    1964 Volume 13 Issue 1 Pages 92-97
    Published: January 15, 1964
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • 1964 Volume 13 Issue 1 Pages 98-111
    Published: January 15, 1964
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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