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Abstract  

The cause of the low detection efficiencies of Cherenkov radiation by the liquid scintillation counter was investigated. The detection limit of the liquid scintillation counter was assumed and the increase of counting rates for the increase of refractive index was calculated from Cherenkov photo yields and -distribution.

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Abstract  

The counting efficiency of Cherenkov radiation by the liquid scintillation counter is studied in several solvents. The relation between the strength of the pulse height by the Cherenkov radiation and the maximum energy of -rays was fairly proportional. The colour quenching can be corrected by measuring the absorbance of solution.

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Abstract  

A rapid method has been developed for the de termination of214Pb and214Bi in natural waters by alpha-spectrometric measurement of214Po. Well water was filtered on a membrane filter impregnated with manganese oxide and followed by direct alpha-spectrometric analysis. A prominent alpha peak was assigned to214Po, which should be supported by the longer lived parents214Pb and214Bi. The activity ratios between214Pb and214Bi adsorbed on the filter were determined by using the change of activity of214Po as a function of counting period after the filtration. The adsorbed yield of214Pb was also determined from the growth of the alpha-peak due to210Po from a210Pb tracer added in the original water. The results indicated that the amount of214Pb was in radioactive non-equilibrium state with the Rn-222 dissolved, while the activity ratios of214Bi/214Pb showed on increasing tendency with the storage period of the water.

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Abstract  

We observed the interference effect of electron-capture X-rays emitted by the nuclear transformations in radioisotopes. This interference is between the direct monochromatic emission from the radioactive atoms and the emission totally reflected by the substrate surface. Nanometer-level structural information about the radioactive atoms can be obtained by analyzing the measured interference fringes because the period of these fringes depends on the position of the radioactive atoms relative to the substrate surface. In this work, we used the functional protein molecules (myosin subfragment 1 (S1)) which were radioiodinated with no carrier added125I to observe the conformational changes in aqueous solutions.

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Abstract  

Aomori Prefectural Govemment and Japan Nuclear Fuel Limited started environmental radiation monitoring around Nuclear Fuel Cycle Facilities in April 1989. External radiation is measured by NaI(TI) scintillator and Themoluminescence dosimeter. The level of external radiation is relatively low in the winter due to snow. We have collected terrestrial samples of drinking water, soil, agricultural products and marine samples of seawater, sea sediment, seafood, etc. periodically. We have measured many radionuclides and fluoride in these samples. In soil sample,239+240Pu ratio to137Cs was almost constant at all sampling points. A correlation was observed between salinity and concentration of tritium, uranium and fluoride in lake water of Lake Obuchinuma. The correlation between137Cs and239+240Pu in lake sediment was observed in each lake.

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Abstract  

The stability constants (β 1) of iodide ion-pairs of trivalent f-block element ions (lanthanoids Ce, Eu, Gd, Tb and Tm, and actinoid Am) were determined in the vicinity of pH 2.5 of mixed methanol/water solvent solutions of an ionic strength of 1.00 mol·dm−3 at 298±1 K. The values were less than 2. From the variation in distance between Eu3+ and I, which was calculated using a Born-type equation for Gibbs’ free energy derived from β 1(Eu), the Eu3+-I interaction was shown to be solvent-shared ion-pair formation when the mole fraction of methanol (X MeOH)≤0.40. In contrast, it was suggested that the interaction of Am3+-I changed from solvent-separated ion-pair to solvent-shared ion-pair with increasing X MeOH when X MeOH≤0.10, but remained as solvent-shared ion-pair in the range 0.16≤X MeOH≤0.40. Furthermore, β 2(Am) was measured in the range 0.31≤X MeOH≤0.40. It was also shown that the β 1 values of lanthanoids at X MeOH = 0.40, except for that of Gd(III), decreased with increasing atomic number.

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Abstract  

A simple method to determine -ray attenuation coefficients using Ba-133 -rays has been developed and applied to self-absorption correction in routine -ray spectrometry for environmental samples composed of unknown matrix elements. Experimental values of the mass attenuation coefficient obtained by the method agree well with calculated values for samples of known elemental composition which was determined by means of chemical analysis.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Yagi, T. Mitsugashira, I. Satoh, M. Hara, Y. Shiokawa, K. Inoue, K. Masumoto, and S. Suzuki

Abstract  

As a new fact, the neutron emission from the d-d nuclear fusion reaction in a SiO2–D2 system has been confirmed as well as that in the Ti–D2 system. By using a liquid scintillation detector, the neutron emissions from 8 sample materials consisted of SiO2, in which a small amount of deuterium was adsorbed chemically on the surface layer, were measured in the range of temperature between liquid nitrogen temperature and 400 °C. As a result, it was demonstrated that the neutron-emission reactions take place predominantly on the surface layer of sample material.

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Abstract  

Aerosol particles of99mTc-labeled carbon were prepared by sublimation and introduced in various liquid media. The adsorption of the aquasol and organosol particles were studied for various adsorbing substances and media, with the effect of surface treatment and voltage application. The particles often accumulated at the aqueous-organic interface, and also on the vessel surface in the presence of both aqueous and organic phases. The distribution of the particles was examined by a gamma-camera for different organic phases under various concentrations of electrolytes in the aqueous phase.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Yagi, Y. Shiokawa, S. Suzuki, M. Hara, I. Satoh, K. Masumoto, and T. Mitsugashira

Abstract  

Neutron emission from the d-d nuclear fusion reaction, D/d,n/3He, in and on titanium metals /titanium sponge and the mixture of titanium powder/ trapped deuterium at about 1 atm has been ascertained by using a high resolution liquid scintillation detector. The neutron emissions from 11 samples which were provided under wide varieties of conditions were measured by temperature change in the range of liquid nitrogen temperature to 350 °C. As a result, it was proved that the neutron emission observed can be divided into two types, such as cooling and heating, by the evolved conditions. Moreover, by estimating the neutron emission efficiencies of samples, it was suggested that the neutron emission reactions are closely related to the deuterium trapped in the surface of titanium metal.

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