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Abstract  

The reaction of238U with12C was studied radiochemically with the purpose of elucidating fast fission characteristics. Fast fission component was extracted in far-asymmetric mass region and interpreted as the mass diffusion following the Fokker-Planck equation. Anomalous charge dispersion widths in the corresponding mass region and a sudden increase of the whole mass distribution width at the critical energy were also observed to support the above interpretation. The reaction time of fast fission was determined to be 5·10−21 s from the width and position of the mass distribution.

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Abstract  

A rapid and precise method of determining radiocesium corresponding to 5 mrem/y, the Japan AEC's guideline, was proposed. The development and practical performance of cesium-selective resin and the determination method was described in this paper. The resin was prepared by the formation of ammonium molybdophosphate in the structure of Amberlite XAD-7 resin. It took only 3 hours to carry out all the procedures the authors proposed. This value represents 1/10∼1/2 of the time of conventional method. The concentration of137Cs and134Cs in sea water was determined to be 0.13∼0.16 pCi/1 and less than 7.1·10−2 pCi/1, respectively.

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Abstract  

The role of the charge degree of freedom in the heavy-ion-induced fission was investigated by carrying out a systematic analysis of radiochemically observed charge distribution in the fission of238U with12C ions of the incident energy between 85 and 140 MeV, particularly in connection with the energy given to the compound system. The charge distribution was found to follow essentially identical systematics as those which govern the light-ion fission except for the extremely weak energy dependence of the most probable chargeZ p. That is, values of the derivative ofZ p with respect to the energy were found to be quite small, or nearly zero, in the heavy-ion fission as compared to those of the light-ion fission. According to an analysis combining the derivatives ofZ p and fission neutron data, it was deduced that the excess energy given to the fused system was spent completely in the form of pre-scission neutrons and hence the number of post-scission neutrons remained constant as in the case of light-ion fission. The observed charge distribution was reproduced under the conditions that the relaxation of the charge degree of freedom be very fast and that the separation between the two potential fragments at the moment when the charge degree of freedom has been frozen is determined by usingViola's systematics on the fragment kinetic energy.

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Abstract  

We have focused on the poly(ethylene glycol) (PEG)-borate ester as a new type plasticizer for solid polymer electrolyte for lithium ion secondary battery. Adding the PEG-borate ester into the electrolyte shows the increase in the ionic conductivity of the polymer electrolyte. By measuring the glass-transition temperature of the polymer electrolytes with DSC, it is found that the increase in ionic conductivity of the polymer electrolyte is due to the increase in ionic mobility. By investigating the temperature dependence of the ionic conductivity of the polymer electrolytes using William-Landel-Ferry type equation, we considered that the PEG-borate ester does not have any influence for dissociation of Li-salt.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
K. Takamiya
,
T. Inoue
,
K. Nakanishi
,
A. Yokoyama
,
N. Takahashi
,
T. Saito
,
H. Baba
, and
Y. Nakagome

Abstract  

In order to estimate the deformation rate of fission fragment at the scission point for thermal neutron-induced fission of233,235U and239Pu, double-velocity and double-energy measurements were carried out. As the result of the estimation of the deformation rate, two types of scission point configurations were found. One type is composed of deformed light and heavy fragments, and the other type is a combination of deformed light and spherical heavy fragments. Mass and total kinetic energy distributions were sorted in two distributions by means of the type of configuration.

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Abstract  

Iron oxides, magnetite Fe3O4 and hematite Fe2O3 were laser-deposited onto Al substrates at various temperatures, and the Mössbauer spectra of the films were measured. The compositions of the films changed depending on the formation temperature of the substrate, oxide deficiency in the lattice structures and the formation process of the iron oxides. The films were composed of Fe3−x O4 and Fe1−x O independent of the laser-evaporation source (magnetite or hematite). Fe3−x O4 was seen to be dominant at higher temperatures and Fe1−x O was dominant at lower temperatures. The compositions of the films were confirmed by X-ray diffraction (XRD) measurements, and the surfaces of the deposited films were examined using scanning electron microscopy (SEM).

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
J. Glatz
,
I. Garcia-Alonso
,
T. Kameyama
,
L. Koch
,
G. Pagliosa
,
T. Tsukada
, and
H. Yokoyama

Abstract  

In order to study the dissolution behavior of a highly burnt LWR fuel, a fuel pin irradiated in the DR3 test reactor in Risoe National Laboratory, has been characterized by microstructural examination and then dissolved under PUREX type conditions. The dissolution behavior was investigated and the residues analyzed by scanning electron microscopy and by ICP-MS and IDMS after dissolution.

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Abstract  

Nuclear reactions of165Ho induced by 1.0 GeV15N or 1.8 GeV14N ions and those of141Pr induced by 2.3 GeV or 3.8 GeV40Ar ions have been studied by off-line -ray spectrometry. Mass distributions of the products were confirmed to reveal a limiting characteristics at projectile energies beyond 2 GeV. Longitudinal momentum transfer was measured with a thick-target-thick-catcher technique. The results demonstrated that a provisional limiting of the recoil velocity appears in the energy range of 2–10 GeV, besides the ultimate limiting condition already pointed out. The coincidence in the onset energy of the limiting behavior was interpreted as the result of the existence of the limit heating of nucleus.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
N. Momoshima
,
H. Kakiuchi
,
T. Okai
,
S. Yokoyama
,
H. Noguchi
,
M. Atarashi
,
H. Amano
,
S. Hisamatsu
,
M. Ichimasa
,
Y. Ichimasa
, and
Y. Maeda

Abstract  

Potted plants were exposed to D2O vapor in a greenhouse and uptake of D2O by leaf and deposition of D2O to pot soil were examined. Atmospheric D2O concentration in the greenhouse increased rapidly after starting the release and reached constant level in a few hours. Although the variation of D2O concentration in leaf followed that in air with showing a time delay, D2O concentration in leaf did not become the same level as that in air and vein showed lower concentration that lamina. D2O concentration in the pot soil increased slowly with diffusing in deeper layer.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
A. Yokoyama
,
S. Morimoto
,
T. Inoue
,
J. Sanada
,
H. Araki
,
T. Saito
,
H. Baba
,
S. Shibata
,
A. Shinohara
,
T. Muroyama
, and
Y. Ohkubo

Abstract  

Target-like products, that is,191–200Au,185–200Pt, and183–195Ir, from197Au target bombarded with12C ions at the energies of 180, 230, and 400 MeV/u were measured by using off-line gamma-ray spectrometry combined with chemical separation procedures. Spallation systematics by Rudstam reproduces well the measured cross sections for formation of platinum and iridium isotopes. It was found that the cross sections of gold nuclides increase with increase of the incident energy in the range studied and they are enhanced if compared with the reported proton-induced reaction of gold at a similar incident energy. It is suggested that the electromagnetic dissociation process plays a role for production of such gold nuclides.

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