Determination of alumina film thickness by alpha particle scattering

The scattering of accelerated alpha particles has been used to determine the surface oxide film thickness of anodized aluminium. The measurements were based on determining the difference between the energy of an alpha particle scattered from the surface oxide layer and that from the underlying metal. Films ranging in thickness from 10 to 130 microg/cm (2) were analysed non-destructively with a relative standard deviation of 3.5 %. The average time for an analysis was 30 min with an incident beam current of up to about 1 microA.     

Secondary ion mass spectrometry and alpha-spectrometry of electrodeposited thorium films

The main aim of this work was the preparation of samples with thorium content on the steel discs by electrodeposition for determination of natural thorium isotope by alpha spectrometry and secondary ion mass spectrometry and finding out their possible linear correlation between these methods. The analysis of the composition of surface was other aim of study. Discs were measured by alpha spectrometer. After that, alpha spectrometry discs were analyzed by TOF-SIMS IV, which is installed in the International Laser Centre in Bratislava. The integral and normalized intensities of isotope of ²³²Th and intensities of ions of ThO⁺, ThOH⁺, ThO₂H⁺, Th₂O₄H⁺, ThO₂ ^?, ThO₃H^?, ThH₃O₃ ^? a ThN₂O₅H^? were measured. The linear correlation is between surface’s weights of Th and intensities of ions of Th⁺ from identified in SIMS spectra. We found out the chemical binding between thorium and oxygen and hydrogen on the surface of samples by SIMS method. Obtained intensities of ions ²³²ThO⁺, ²³²ThOH⁺, ²³²ThO₂H⁺ prove the presence of oxidized forms of thorium in the upper layers of surface. The oxidized ions predominate in univalent form of thorium up to deep about 3,000 nm.     

Determination of thorium with DBF-arsenaz by flow-injection analysis

A sensitive,selective,rapid,simple,and convenient method for the determination of thoriumwas developed.The method was based on the color reaction of thorium with DBF-arsenazo in astrong acidic medium (4 mol/L HCI).The flow-injection technique was used with an automated flow-injection analyzer.Beer's law was obeyed in the range of 0—1.4 μg/mL.The relative standarddeviations were less than 1%.     

Determination of thoria in thorium ores by an emission spectrographic method

The emission spectrograph is used to determine thoria in monazite sand. A sample of only 15 mg is required and yields rapid and accurate results for 2% thoria or less. Of various additives tested as carriers, carbon and MoO₃ were found to be best. A current of 6 A gave a proper rate of volatilization without excessive spattering. The 267.28 nm Mo line was used as internal standard and the 269.24 nm Th line for analysis. Silica and iron sulphide were used as matrix in synthetic samples. Results compared well with those obtained by wet-analysis.     

Determination of fluoride with thorium nitrate by catalytic titration

Amperometry, constant-current potentiometry and spectrophotometry were used to follow the course of catalytic titrations of fluoride and silicofluoride with thorium nitrate. The hydrogen peroxide-iodide system was used as the indicator reaction. Titrations were performed in 50% ethanolic acetate buffer, pH 3.6. Amounts of 3.70-6.85 mg of ammonium fluoride, 5.53-10.79 mg of potassium fluoride and 4.34-8.41 mg of sodium silicofluoride were determined with a maximum average deviation of 0.9%. The results obtained are in good agreement with those of comparable methods.     

Determination of thorium in the range of low concentrations

Summary Methods for the determination of Th in the range of low concentrations are compiled and discussed. Application of spectrophotometry and voltammetry is investigated. Spectrophotometry is applicable down to concentrations of the order of 0.1 g/l as long as the ratio U:Th is low. Voltammetric determination of Th is not possible in the presence of Al.     

Determination of protactinium-233 in irradiated thorium

A method has been devised for the absolute determination of ²³³pa in irradiated thorium meta1 by counting the β-emission of chemically separated and purified sources. The counter was calibrated by a source of ²³⁷Np of known activity in equilibrium with its 233Pa daughter, and checked by 4 π counting     

Determination of thorium isotopes in bastnaesite ores

A procedure for the determination of alpha-emitting thorium isotopes in bastnaesite ores has been developed. The refractory sample was completely decomposed by potassium fluoride fusion in a platinum crucible followed by transposition to a pyrosulfate fusion. The pyrosulfate cake was dissolved in HCl and the resulting precipitate dissolved in DTPA solution; thorium was coprecipitated as hydroxide using cerium present in bastnaesite as natural carrier. Thorium was then extracted into a TOPO solution, separated by using Dowex 1-X8 for anionic exchange, electrodeposited and finally analyzed by alpha-spectrometry. Thorium was also determined spectrophotometrically using Arsenazo as a colorimetric reagent. The thorium yield of the above discussed chemical procedure is more than 85%.     

Determination of reactor neutron spectra with multicomponent activation detectors

A procedure is described for the functional fitting of reactor neutron spectra with C/Eⁿ and fission spectra. The method is applied to multicomponent activation detector measurements in a Triga research reactor. In multicomponent detectors a mixture of several detector materials is irradiated as a single unit and measured simultaneously for all reaction products with a Ge(Li) gamma ray spectrometer.     

Determination of uranium isotopes in irradiated thorium dioxide by alpha spectrometry using WinALPHA for deconvolution of complex spectra

Isotopic composition of uranium obtained from irradiated thorium dioxide was determined using alpha spectrometry by employing WinALPHA for the deconvolution of the alpha spectra recorded using electrodeposited sources. The results obtained were found to agree within 1% with those determined by thermal ionization mass spectrometry. The deconvolution methodology is important since it is possible to account for the in-growth of ²²⁸Th, which interferes in the determination of ²³²U by alpha spectrometry. The present methodology has the potential to determine isotopic composition of uranium in the irradiated thorium based nuclear fuels, employing alpha spectrometry.     

Porous cobalt hydroxide film electrodeposited on nickel foam with excellent electrochemical capacitive behavior

A new porous cobalt hydroxide film has been successfully electrodeposited on nickel foam from 0.1?M cobalt nitrate electrolyte at ?1.0?V vs. SCE without adding any surfactant. The microstructure and surface morphology of prepared cobalt hydroxide films were physically characterized by X-ray diffraction analysis and scanning electron microscopy. The results indicate that an interlaced network structure was obtained. The effects of electrodeposition time, deposition potential, and different substrates on the specific capacitance and microstructure of prepared porous ??-Co(OH)₂ thin film were systematically studied. The results indicate that the film deposited on nickel foam at ?1.0?V has excellent electrochemical properties. A maximum specific capacitance of 1473?F?g^?1 could be achieved at a current density of 2?A?g^?1.     

Determination of thorium in the organs of deceased thorotrast patients

Thorotrast was widely used in the past as an X-ray contrast medium, containing a colloidal solution of thorium dioxide (²³²ThO₂). After injection, thorium accumulates and is mainly retained in the liver. Thus once Thorotrast is administered, patients might be chronically exposed to -radiations. Recently, significant development of cirrhosis and cancer of the liver has often been noted among Thorotrast patients. Additionally the incidence of lung and breast disease has significantly increased. Thus, the assessment of internal radiation dose from deposits of Thorotrast is very important. In this report, the thorium content in various organs was determined by means of neutron activation analysis. All the samples were taken from organs of Thorotrast patients subsequent to death. The ashed samples were irradiated in a reactor. After cooling, the content of thorium was determined by measurement of gamma rays resulting from the decay of protactinium-233. For comparison, measurements by other analytical methods such as inductively coupled plasma mass spectrometry, colorimetric analysis using ArsenazoIII and radiation measurement of -rays from actinium-228, were carried out.     

The electrodeposition of thorium in natural materials for alpha spectrometry

A technique has been developed for the electrodeposition of thorium on stainless stell planchettes following standard radiochemical separation and uptake in acetate buffer. The method has been used on over 130 samples including calcrete, clay, granite and shell matrices. To assess the efficiency at ultra low levels, three solutions of carrier free²²⁸Th (<1.5–10⁻⁷ μg in 5 ml electrolyte) and four solutions of²²⁹Th (4.4–10⁻⁴ μg in 5 ml) were studied. The efficiencies of the former avaregad 66 per cent; those of the²²⁹Th varied from 41 to 91%.     

Oligomer-immobilizing ability of an electrodeposited aramid resin film in the electrooxidation of aniline derivatives and the functions of the resulting films

An aramid resin, poly(p-phenylene terephthalamide) (PPTA), was electrodeposited on an indium-tin oxide electrode as a mechanically stable film from a dimethyl sulfoxide solution. Two aniline derivatives, o-phenylenediamine and o-aminophenol, were electrooxidized from H₂SO₄ aqueous solutions using the PPTA film-coated electrode. The PPTA film was permeable to the aniline derivatives, and the derivatives were electrooxidized on the electrode surface. When the derivatives were electrooxidized, the film immobilized the corresponding oligomer species as well as the polymers plain (o-phenylenediamine) (PoPD) and poly(o-aminophenol) (PoAP), and the deposited amount of the polymers was increased by the PPTA film. The immobilized amount of PoAP was greater than that of PoPD because of the 1,4-substituted structure of PoAP. In the PPTA film, both PoPD and PoAP were electronically stabilized, and they became durable against oxidative degradation.     

Raman spectroscopic investigation of film thickness

The determination of film thickness is of prime importance in the quality assurance of coated pharmaceutical preparations. The rapid measurement of this parameter is problematic for multi-particulate pellet systems. The aim of this study was to apply the Raman spectroscopic method for the determination of the thickness of polymer coating on pellets. The change of Raman intensity was compared with measured film thickness, which was calculated from the change of the geometric parameters of the pellets, measured with an image-analyzing system. The results revealed that despite some difficulties Raman spectroscopy is a suitable method for the fast and accurate determination of film thickness on multi-particulate systems.     

Determination of microgram quantities of uranium in thorium

Uranium present in micro amounts in thorium is extracted with 5% tributyl phosphate in presence of EDTA at pH 2.5. Calcium nitrate is used as salting agent. Uranium is back-extracted with ammonium carbonate and determined fluormetrirically. Thoria samples containing as little as 0.4 p.p.m. of uranium have been analysed.     

Determination of zirconium,thorium and scandium with 2,5-dihydroxy-1,4-benzoquinone

Zirconium is quantitatively precipitated by 2,5-dihydroxy-1,4-benzoquinone and is separated from scandium in 1 N hydrochloric acid solution. Thorium is separated at pH 0.5 from uranium(VI), cerium(IV), lanthanum, yttrium and scandium. Scandium is quantitatively precipitated by this reagent in the pH range 1.4–2.0 and at pH 1.5 equivalent amounts of lanthanum do not interfere; small amounts of yttrium cause interference.