X-ray photoelectron study of murataite ceramics containing Th, U, Np, and Pu

The structure of X-ray photoelectron spectra of actinide-containing (An = Th, U, Np, and Pu) murataite ceramic (Ti-Mn-Ca-An-Zr-Al-Fe-O) samples as potential matrices for immobilization of actinide radioactive waste was studied. The elemental composition of the sample surface was analyzed, and comparison with the calculated data for the bulk of the samples was made. The binding energies of the An4f electrons and the parameters of the fine structure of their X-ray photoelectron spectra were determined. These parameters were compared with the corresponding values for the dioxides.     

Aluminum (Iron) Phosphate Glasses Containing Rare Earth and Transuranium Elements: Phase Composition,Oxidation State of Np and Pu,and Hydrolytic Durability

Samples of aluminum (iron) phosphate glasses containing weighable amounts of rare earth and transuranium elements were synthesized. The quenched glasses obtained are X-ray amorphous, and in the course of annealing they undergo partial crystallization with segregation of a poorly soluble phase of monazite structure. However, the hydrolytic durability of the glasses remains on the level meeting the requirements to immobilized high-level waste (no more than 10^–7 g cm^–2 day^–1). Plutonium in the surface layer of the glass samples occurs in oxidation state IV, and neptunium, mainly in oxidation states IV and V.     

The activation of oil-insoluble antifriction additives

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 17–19, March 1991.     

X-ray photoelectron study of the MoCl2C30H30 composite

The surface of a MoCl₂C₃₀H₃₀ composite in the form of molybdenum nanoclusters in a polyacetylene matrix, produced by reacting MoCl₅ with C₂H₂ in benzene and toluene, has been studied by X-ray photoelectron spectroscopy before and after Ar⁺ ion milling. The composite actively reacts with atmospheric oxygen and moisture. As a result, the molybdenum clusters on its surface oxidize to molybdenum(V) or molybdenum(VI) oxides or oxychlorides (E _b(Mo 3d _5/2) = 232.3–232.5 eV) during the sample preparation process. The electron binding energy of molybdenum affter surface etching (E _b(Mo 3d _5/2) = 228.5 eV) suggests that the oxidation state of the molybdenum in the composite is 2⁺ or 3⁺. Analysis of the structure of the spectrum of the C 2s electrons of the inner valence molecular orbitals using the energy level diagram of the C₂ molecule suggests that the hydrocarbon matrix of the composite contains, in addition to-CH=CH-CH=CH- conjugate bonds, linear carbyne fragments: -HC=C=CH- or -C≡C-. After etching, the surface layer of the composite contained argon, which might be due to adsorption because of the small particle size of the composite or chemisorption on the surface of the polyacetylene matrix. The composite is stable in a high vacuum of 1.3 × 10⁻⁵ Pa up to 350°C and does not experience charging when exposed to X-rays, which indicates that it has weak dielectric properties.     

Application of the photomult plier FEU-12 to scintillation spectroscopy

An investigation was made of the spectral response and other characteristics of the FEU-12 photomultiplier having grid-type dinodes and developed by G. S. Vildgrube.The authors consider it their pleasant duty to thank Mr. G. S. Vildgrube who made available to them photomultipliers and certain materials for technical tests.     

Surface composition and morphology of a carbon matrix/Mo<Subscript>2</Subscript>C composite material

The surface composition and morphology of a carbon matrix/Mo₂C composite have been studied by scanning electron microscopy and X-ray photoelectron spectroscopy. The results demonstrate that the carbon matrix has the form of entangled filaments of carbon nanotubes. The surface layer of the composite contains 57 carbon atoms per molybdenum atom. Molybdenum is present here in the form of the Mo₂C carbide (39 at %) and the Mo₂O₅ (50 at %) and MoO₂ (11 at %) oxides, with E _b(Mo 3d _5/2) = 228.2, 229.6, and 231.9 eV, respectively. The presence of the Mo⁴⁺ and Mo⁵⁺ oxides in the surface layer is due to active reaction of the Mo₂C in the composite with atmospheric oxygen and moisture during the sample preparation process and can be accounted for by the small particle size of the material. Based on analysis of the structure of the C 2s and C 2p valence electron spectra, we assume that the carbon nanotubes of the composite are graphitelike carbon structures. The composite studied here does not become charged when exposed to an X-ray beam, which suggests that it is a weak dielectric.     

Structure of the XPS Spectra of a ThO2 Crystal Film

Radiochemistry - The complex structure of precision X-ray photoelectron spectra (XPS) of valence and core electrons of a ThO2(001) crystal film on Si(100) was obtained and analyzed, and the...