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  • Author or Editor: H. Kudo x
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Abstract  

When neutron-irradiated Li(1 wt%)-Al alloys were heated under vacuum at temperatures above 770 K, more than 95% of tritium was extracted in the gas phase within 1 h. The predominant species of extracted tritium were HT and HTO, although the distribution of both species varied depending upon the extraction temperature. The specific activity of the HT fraction was found to change within wide limits also depending upon the extraction temperature. The phenomenon was attributed to the difference in the release behaviour between tritium produced by the6Li(n, α) T reaction and protium contained as impurity in the alloy.

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Abstract  

Gamma-rays of nuclides of uranium and thorium series in silicone resin and ceramics were measured with a Ge(Li) detector. The state of radioactive equilibrium was determined by comparing the concentrations of uranium and thorium with the radioactive concentrations of214Pb and212Pb. The radioactive equilibrium was attained in silicone resin but not in ceramics. The -flux was calculated from the concentrations of uranium and thorium and their daughter nuclides. The calculated values of -flux agreed with that of -flux measured.

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Abstract  

A method of radioactivation analysis has been developed for the determination of indium and tin. It is based on substoichiometric extraction of indium diethyldithiocarbamate into carbon tetrachloride from a slightly ammoniacal solution in the presence of potassium cyanide. With this method, indium can be determined via116mIn (T=54 min) and tin via113mIn (T=104 min) which is formed by the reaction112Sn(n, ψ)113Sn. The method has been applied to the determination of indium in metallic zinc and of tin in tin-doped gallium arsenide, and 0.4 ppb of indium was analyzed in a zinc sample.

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Abstract  

Polyethyleneglycol (PEG) and its derivatives of high molecular weight were found to be employed as useful extractants for the solvent extraction of uranium. The extraction behaviors of uranium and neptunium were investigated, particularly concerning the dependence of the extractibility of uranium(VI) on the molecular weight of PEG. A dominating species of the extracted uranium(VI) thiocyanate complexes was assumed to be NH4 UO2(SCN)3·(PEG). The extraction of protactinium was also preliminarily studied. The extraction of these actinides from an acidic thiocyanate solution increased in the order: uranium(VI)>protactinium(V)>neptunium(V).

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Abstract  

We calculate the energy levels of the metastable states of an antiprotonic helium atom. The coupled rearrangement channel method is employed to describe a dual character of the atom effectively. Calculated transition frequencies between the metastable states are in good agreement with the observed values. The uncertainty of an antiproton mass is estimated by the calculated transition frequencies with the slightly shifted antiproton mass from the proton mass. When a more accurate value of the charge-to-mass ratio of antiproton is considered, the uncertainty of antiproton mass and charge is estimated at 54 ppb which improves the value recommended by the particle data by a factor of ten.

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Abstract  

Oxygen in silicon was determined by the secondary nuclear reactions of6Li(n, α)T and16O(t, n)18F. Lithium fluoride was deposited in vacuum on fused quartz, covered with the sample and irradiated in a nuclear reactor. The depth profiles of18F in fused quartz and in silicon were observed, and enough depth to eliminate surface oxygen was estimated. On the basis of these results, oxygen was determined by the average cross-section method. Oxygen concentration in CZ silicon with various growing condition was 5–26 ppm and was consistent with those determined by the infrared absorption method. The detection limit of oxygen in silicon is 5 ppm.

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Abstract  

The substoichiometric determination of some impurities in gallium arsenide and selenium supplied by OEC and IUPAC, respectively, as reference materials for radioactivation analysis is described.

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Abstract  

Theoretical calculations based on the density functional theory (DFT) were performed to understand the effect of substituents on the molecular and electronic structures of technetium nitrido complexes with salen type Schiff base ligands. Optimized structures of these complexes are square pyramidal. The electron density on a Tc atom of the complex with electron withdrawing substituents is lower than that of the complex with electron donating substituents. The HOMO energy is lower in the complex with electron withdrawing substituents than that in the complex with electron donating substituents. The charge on Tc atoms is a good measure that reflects the redox potential of [TcN(L)] complex.

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Abstract  

Chemical states of tritium existing in neutron-irradiated solid lithium compounds were analyzed using a radiometric method. Nearly 100% of tritium was found in the T+ state in LiOH, Li2O2 and Li3N, while the T state predominated in LiH, Li7Pb2 and Li2C2. Tritium incorporated in Li2O, Li2S, LiF, LiCl, LiBr and LiI was distributed over the T+, T and T0 states. In Li2O crystals, the distribution of tritium in the T+ state increased from 58% to 81% with increasing neutron fluence from 2.5×1016 cm–2 to 6.3×1017 cm–2.

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Abstract  

The reaction of [TcNCl2(PPh3)2] with 2,2′:6′,2″-terpyridine producedcis-[TcNCl2(terpy)] selectively. The resulting complexes were characterized by1H NMR and IR spectroscopy. The geometries of thecis andtrans isomers were estimated by theoretical calculations following a density functional method. Thecis isomer is likely more stable than thetrans one with respect to thetrans influence of the nitrido ligand. Furthermore, the behavior of nitridotechnetium complexes in polar solvents was compared to Os-analogues.

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