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Rapid determination of molar ratios in binary systems by 14 MeV neutron activation analysis
Determination of the molar ratio of iron(III) oxide and barium oxide in barium ferrite
Abstract
The magnetic characteristics of barium ferrite, a compound widely used for magnetic materials, depend on the molar ratio of iron(III) oxide to barium oxide. On account of this fact, activation analysis using 14 MeV neutrons was applied for the rapid and non-destructive determination of the molar ratio of iron(III) oxide to barium oxide in barium ferrite. Iron was detected as56Mn produced from the56Fe(n, p)56Mn reaction, and barium as137mBa originating from the138Ba(n, 2n)137mBa reaction. A linear relation was obtained between the ratio of counts of56Mn and137mBa and the molar ratio of iron(III) oxide to barium oxide; the corrected gradient of the experimental calibration curve, obtained with137mBa internal standard, agreed well with the calculated value. The molar ratios of iron(III) oxide to barium oxide obtained by activation analysis and by chemical analysis were in good agreement.
Rapid determination of molar ratios in binary systems by 14 mev neutron activation analysis
Determination of molar ratios of iron(III) oxide and zinc oxide in zinc ferrites
Abstract
The 14 MeV neutron activation analysis method was applied for the rapid and non-destructive determination of the molar ratios of iron(III) oxide and zinc oxide in zinc ferrites. Iron was detected as56Mn produced from56Fe by the (n, p) reaction, and zinc as the sum of the coincidence counts of the annihilation radiations of the positrons emitted from63Zn and64Cu produced from64Zn by the (n, 2n) and (n, p) reactions respectively. The ratios of the counts of56Mn and the sum of the coincidence counts were not linearly related to the molar ratios of iron(III) oxide and zinc oxide in zinc ferrites. However, by corrections of the mutual contributions to the counts, linear relations were obtained between the ratios of the counts and the molar ratios when the corrected sum of the coincidence counts was used as an internal standard. The experimental and theoretical slopes of the analytical lines agreed within a difference of approximately 10%. The deviations between the results of the activation analysis and those of the chemical analysis were less than 5% of the chemical results.
Determination of silicon in cast iron by 14 MeV neutron activation
High-resolution gamma-ray spectrometry with a56Mn internal standard
Abstract
Silicon in cast iron was analyzed by 14 MeV neutron activation—high-resolution γ-ray spectrometry. Silicon was detected as28Al, the product of the28Si(n, p)28Al reaction. Interference of56Mn was separated using a Ge(Li) detector and a biased amplifying system. The 1. 81 MeV gamma-radiation of56Mn, which is the product of the56Fe(n, p)56Mn reaction of the matrix of cast iron, was used as an internal standard and for correction of the self-absorption of the 1. 78 MeV gamma-radiation of28Al by the sample. The interferences of aluminum, phosphorus and manganese could be neglected according to the results calculated from their nuclear properties and contents in the cast iron of this experiment. The results of this method agreed well with the results of the usual chemical method, with errors less than 5% of the results, and the precision of the method was satisfactory with a C. V. of less than almost 6% for rapid analysis of silicon in cast iron. The analytical line through the origin with a slope of the mean value of the repetition experiments could be used as the analytical line with almost the same precision and accuracy of the results as for the analytical line calculated by the least squares method.
Abstract
Silicon as silicon dioxide in iron and steel-making slags and fluorspars was analyzed by 14 MeV neutron activation high-resolution γ-ray spectrometry. Silicon was detected by measuring the 1.78 MeV γ-ray of28Al, the product of the28Si(n, p) reaction, using a 30 cm3 coaxial Ge(Li) detector. A modified TPA method was used for the calculation.28Al is also produced from phosphorus by the31P(n,α) reaction, and from aluminium by the27Al(n,γ) reaction. The contribution from the former reaction could be corrected experimentally when the P2O5 content of the sample was known, while the latter reaction could be neglected in this neutron energy region. The experimental correction coefficient for phosphorus agreed well with the theoretical value calculated from the nuclear properties of silicon and phosphorus. Yields of28Al from SiO2, P2O5 and Al2O3 of the same weight percentages were calculated as 1, 0.426 (experimentally 0.44) and 0.0022, respectively. The results of this method agreed well with the results of the usual chemical methods. The limit of detection of SiO2 in iron and steel-making slags and fluorspars was calculated as 0.07%. The coefficient of variation of repeated experiments was compared with the statistical one.
Abstract
Distribution of samarium (Sm) in mice was investigated after inhalation exposure to Sm2O3 particles of 5 μm diameter and 15 mg/m3. Concentrations of Sm were determined by ICP-MS. Samarium was mainly distributed in lung, and the concentrations were varied, depending on the exposure length and time passed following final inhalation. Samarium concentrations in bone were lower than in lung, however, increased after cessation of the inhalation, suggesting that a part of Sm in lung was transported to bone via the blood stream.
Summary
Drinking water in developed countries is usually treated by the water-purification system, while in developing countries untreated natural water such as well water, river water, rain water, or pond water are used. On the other hand, many kinds of mineral water bottled in plastic containers are sold as drinking water with or without gas in urban areas in many countries. Seawater under hundreds meters from the surface is also bottled and sold as drinking water with advertising good mineral balance. Various element concentrations in water samples for drinking were analyzed, and then it was considered the effects of elements on human health.
Abstract
Environmental conditions were evaluated by element concentrations in hair of children living near the Aral Sea. Hair samples were provided by 63 children living near the Sea (K-district), and 143 children living about 600 km from the Sea (Z-district). PIXE was applied for the determination of elemental concentrations. The concentrations of Br, Na, Hg, and Ni were higher in K-district, and those of Al, Ca, Cr, P, S, and Si were higher in Z-district than in the other district, respectively. It is considered that these results reflect the environmental situation.
