From the measured gamma-ray spectra, activity concentrations are determined for (238)U, (232)Th and (40)K. The mean acti … Determination of uranium, thorium and potassium activity concentrations in soil cores in Araba valley, Jordan Radiat Prot Dosimetry. 2008;128(2 ... Thorium / analysis*
Uranium and thorium as natural radioactive elements are present everywhere in the environment. Their trace levels are also present in various materials, such as copper, used as a shielding material in gamma-ray spectrometry, usually located very close to the detector. Ultra-low levels of uranium and …
Work on various methods of assay of uranium and thorium in ores by purely radiometric methods are described. Some of the methods are applicable only to ores containing either uranium or thorium separately, and some can be used when a mixture of the two is present in one ore. ... The minimum concentraiions that can be determined are 0.005% …
Hellstrom, in his article, recommended a wider application of the improved uranium-thorium dating method. It is actually a 50-year-old technique, but a vastly improved one. Cave art is typically ...
Laser-induced breakdown spectroscopy (LIBS) has been developed for determining the percentage of uranium in thorium-uranium mixed oxide fuel samples required as a part of the chemical quality assurance of fuel materials. The experimental parameters were optimized using mixed oxide pellets prepared f …
The amounts of uranium and thorium in the sample mixtures prepared in similar way as the calibration mixtures were determined using the aforementioned calibration plots.
The concentrations of thorium and uranium are determined using the distinctive emission peaks associated with 208Tl and 214Bi 22. ... Unlike potassium and uranium, thorium has lower mobility.
These two elements react with the dyestuff in hydrochloric acid and acetate-buffered methanolic solution respectively forming colored complexes which can be applied for the quantitative spectrophotometric determination of both thorium and uranous ions. 5 mu g thorium or 20 mu g uranium(IV)/ 10 ml measuring solution can be determined with a ...
Thorium fuels, therefore, complement uranium fuels and ensure long term sustainability of nuclear power. • Thorium fuel cycle is an attractive way to produce long term nuclear energy with low radiotoxicity waste. In addition, the transition to …
1829 Jöns Jacob Berzelius determined that the rock called thorite contained a new element, thorium. ... So as magma cools, uranium and thorium are some of the last elements to be incorporated into crystals so the melt component of the magma becomes progressively enriched in uranium, thorium and other incompatible elements. In turn, …
1829 Jöns Jacob Berzelius determined that the rock called thorite contained a new element, thorium. ... So as magma cools, uranium and thorium are some of the last …
Pomegranate peel was investigated as biosorbent to remove uranium as well as thorium from aqueous solutions under different experimental conditions (concentration, counter ions, temperature). The material was used in raw and modified form after treatment with acidic and alkaline solutions to increase its sorption capacity. …
Large part of available literature on biogeochemistry of uranium and thorium refers to the studies performed either in highly contaminated areas or in nutrient solutions that have been artificially 'spiked' with radionuclides. Effects of background levels of natural radioactivity on soil-grown plants have not been studied to the same extent.
The concentrations of uranium-238 and thorium-232 were determined by direct counting using a hyper pure germanium (HPGe) detector inter phased with a multi channel analyzer (MCA) . Results showed ...
The behavior of uranium and thorium is also influenced by their speciation and low pH conditions. Uranium is present as a positively charged uranyl ion UO22+ in low pH samples and is very mobile. ... 228 Ra was determined by beta counting, whereas a paper filter was used to screen the alpha particles of 226 Ra. Corrections were made if …
The impurities of uranium and thorium at ultra-low levels in electrolytic copper using RNAA via their induced nuclides U-239/Np-239 and Pa-233, were determined. Obtained results showed that electrolytic copper samples contained impurities of uranium and thorium in ultra-trace levels: up to 45 pg/g (550 nBq/g) for uranium and …
This paper describes the identification and quantification of uranium, thorium and other chemical elements in a low-grade uranium ore, using macro and micro-X-ray fluorescence scanning. The result of such scanning is their surface distribution determined in flat samples.
Abstract. We have re-determined the 234 U and 230 Th half-lives to be 245,250 ± 490 years (2σ) and 75,690 ± 230 years (2σ), respectively. Using high precision thermal ionization mass spectrometric (TIMS) methods, we measured 234 U/ 238 U and 230 Th/ 238 U atomic ratios in 4 different materials that were likely to have behaved as closed ...
We determined the amounts of uranium or thorium (by injection, ingestion, or inhalation) in soluble compounds leading to a committed effective dose of 200 mSv. These amounts of uranium or thorium were considered to be critical values in the case of a nuclear or radiological incident regarding stochastic radiation damages. As for the …
The actinides are thought to have been generated by the rapid neutron capture (r)-process in a supernova at the origin of the solar system (4.6 × 10 9 an ago) …
Thorium boasts several advantages over the conventional nuclear fuel, uranium-235. Thorium can generate more fissile material (uranium-233) than it consumes while fuelling a water-cooled or molten-salt reactor.According to estimates, the Earth's …
Half-lives have been determined in laboratories for many radioisotopes (or radionuclides). These can range from nearly ... The three naturally-occurring actinide alpha decay chains given below—thorium, uranium/radium (from uranium-238), and actinium (from uranium-235)—each ends with its own specific lead isotope (lead-208, lead-206, and ...
Concentrations of multielements including REEs and thorium have been determined by k 0-based internal monostandard INAA (IM-INAA) method in the presence of uranium in minor or trace quantity. Thorium is determined by INAA by measuring gamma rays of 300 and 312 keV of 233 Pa (26.97 d), the daughter product of activation …
Radioactive heat productionA is a scalar and isotropic petrophysical property independent of in situ temperature and pressure. Its value is usually expressed in HGU units (1 HGU=10 −13 cal/cm 3 sec) and depends on the amounts of uranium, thorium and potassium. A varies with rock type over several orders of magnitude and reflects the geochemical …
uranium-thorium-lead dating, method of establishing the time of origin of a rock by means of the amount of common lead it …
The mineral composition was determined by X-ray diffraction (XRD) and uranium and thorium-bearing minerals were identified by electron probe micro-analysis …
Model samples contained the known concentrations of uranium and thorium. After preconcentration and separation, thorium and uranium were …
The uranium and thorium contents in the soils and bottom sediments of the Lake Bolshoye Yarovoye natural system correspond to the data for the steppe climate zone and are noticeably lower than the background values for the Altai Territory as a whole. Factors that reduce the content of uranium and thorium are: 1 - lighter grain size …
Uranium–thorium dating is commonly used to determine the age of calcium carbonate materials such as speleothem or coral, ... Berzelius made some initial characterizations of the new metal and its chemical compounds: he correctly determined that the thorium–oxygen mass ratio of thorium oxide was 7.5 (its actual value is close to that, ...
Measurements of the lead isotopic composition and the uranium, thorium, ... The newly determined value of the lead isotopic composition of Canyon Diablo troilite is as follows: …
Uranium and thorium are both determined by inductively coupled plasma mass-spectrometry using an isotope dilution method. While standard and spike solutions can be purchased, their isotopic composition and the concentration of the standard solution need to be verified. Digestion procedures for apatite and fluorite are relatively straightforward ...
