The Experts below are selected from a list of 7650 Experts worldwide ranked by ideXlab platform
Michael E Ketterer - One of the best experts on this subject based on the ideXlab platform.
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envirogeochemical exploration for norm wastes quadrupole inductively coupled plasma mass spectrometric measurements of thorium and Uranium Isotopes
Journal of Analytical Atomic Spectrometry, 2000Co-Authors: Michael E Ketterer, James A Jordan, Scott Szechenyi, David D Hudson, Rick Robert LaymanAbstract:Naturally occurring radioactive material consists of 238U, 235U and 232Th and series daughters; it is released into the environment from many anthropogenic sources. The use of quadrupole ICP-MS is well-suited to site investigations of releases of naturally occurring radioactive material through measurements of the ratios 232Th∶230Th, 230Th∶238U and 234U∶238U. Each ratio measurement may potentially indicate the contrast between the geochemical background and the affected environment. 232Th∶230Th was measured in samples prepared by fusion or selective extraction; Th was concentrated using TRU-Spec extraction resin and isotopic measurements were made with 5–10 µg Th. The precision is ≈1% (2σmean) and 10% for 232Th∶230Th of 1 000 and 100 000–200 000, respectively. Thorium isotopic measurements were applied to studies of accumulation of 230Th in phosphate-fertilized lawns. The ratio 230Th∶238U was determined via combining separate measurements of 230Th∶232Th and 232Th∶235U or 232Th∶238U; a 230Th∶238U precision of 1–2% (2σmean) is reported for a phosphate fertilizer sample. This 230Th∶238U measurement scheme requires no synthetic yield tracers, and is applied to studies of deposition of U mill tailings in an affected river basin. The ratio 234U∶238U was determined in natural waters following a two-stage extraction with Chelex 20 and UTEVA resins; a precision of ≈0.3–0.5% (2σmean) is attained for sample concentrates containing 15–25 µg U. 234U∶238U measurements are useful in distinguishing between dissolved U from natural weathering versus mining/milling sources.
Rick Robert Layman - One of the best experts on this subject based on the ideXlab platform.
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envirogeochemical exploration for norm wastes quadrupole inductively coupled plasma mass spectrometric measurements of thorium and Uranium Isotopes
Journal of Analytical Atomic Spectrometry, 2000Co-Authors: Michael E Ketterer, James A Jordan, Scott Szechenyi, David D Hudson, Rick Robert LaymanAbstract:Naturally occurring radioactive material consists of 238U, 235U and 232Th and series daughters; it is released into the environment from many anthropogenic sources. The use of quadrupole ICP-MS is well-suited to site investigations of releases of naturally occurring radioactive material through measurements of the ratios 232Th∶230Th, 230Th∶238U and 234U∶238U. Each ratio measurement may potentially indicate the contrast between the geochemical background and the affected environment. 232Th∶230Th was measured in samples prepared by fusion or selective extraction; Th was concentrated using TRU-Spec extraction resin and isotopic measurements were made with 5–10 µg Th. The precision is ≈1% (2σmean) and 10% for 232Th∶230Th of 1 000 and 100 000–200 000, respectively. Thorium isotopic measurements were applied to studies of accumulation of 230Th in phosphate-fertilized lawns. The ratio 230Th∶238U was determined via combining separate measurements of 230Th∶232Th and 232Th∶235U or 232Th∶238U; a 230Th∶238U precision of 1–2% (2σmean) is reported for a phosphate fertilizer sample. This 230Th∶238U measurement scheme requires no synthetic yield tracers, and is applied to studies of deposition of U mill tailings in an affected river basin. The ratio 234U∶238U was determined in natural waters following a two-stage extraction with Chelex 20 and UTEVA resins; a precision of ≈0.3–0.5% (2σmean) is attained for sample concentrates containing 15–25 µg U. 234U∶238U measurements are useful in distinguishing between dissolved U from natural weathering versus mining/milling sources.
M Thoennessen - One of the best experts on this subject based on the ideXlab platform.
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Discovery of actinium, thorium, protactinium, and Uranium Isotopes
Atomic Data and Nuclear Data Tables, 2013Co-Authors: C. Fry, M ThoennessenAbstract:Currently, 31 actinium, 31 thorium, 28 protactinium, and 23 Uranium Isotopes have so far been observed; the discovery of these Isotopes is discussed. For each isotope a brief summary of the rst refereed publication, including the production and identication method, is presented.
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discovery of the actinium thorium protactinium and Uranium Isotopes
arXiv: Nuclear Experiment, 2012Co-Authors: C. Fry, M ThoennessenAbstract:Currently, 31 actinium, 31 thorium, 28 protactinium, and 23 Uranium Isotopes have so far been observed; the discovery of these Isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.
Andrew Entwistle - One of the best experts on this subject based on the ideXlab platform.
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validation of the analytical linearity and mass discrimination correction model exhibited by a multiple collector inductively coupled plasma mass spectrometer by means of a set of synthetic Uranium isotope mixtures
Journal of Analytical Atomic Spectrometry, 1995Co-Authors: P D P Taylor, Paul De Bievre, Andrew J Walder, Andrew EntwistleAbstract:A set of commercially available synthetically prepared mixtures of Uranium Isotopes (IRMM 072) were used to assess the linearity and mass discrimination exhibited by a multiple collector ICP-MS instrument. Measurements of eight Uranium isotopic reference materials with 233U : 235U isotope abundance ratios ranging from 1 to 0.01 were made. Linear, power law and exponential relationships between instrumental mass discrimination and mass difference were evaluated. The power law and exponential function resulted in the best correction. The corrected isotope abundance ratios for 233U : 235U and 233U : 238U did not differ significantly from the certified values at the 3 × 10–4 level.
Osamu Iwamoto - One of the best experts on this subject based on the ideXlab platform.
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development of a comprehensive code for nuclear data evaluation ccone and validation using neutron induced cross sections for Uranium Isotopes
Journal of Nuclear Science and Technology, 2007Co-Authors: Osamu IwamotoAbstract:A new comprehensive code for nuclear data evaluation, CCONE, has been developed for the evaluation of nuclear data for actinides. Neutron-induced reaction cross sections for Uranium Isotopes (A = 232, 233, 234, 235, 236, 237, 238) were analyzed for incident energies from 10keV to 20MeV using CCONE in order to validate its capability. Reproducibility of the cross section calculations for various reactions such as total, fission, capture, and (n, 2n) was tested using simple parameterization. The calculated cross sections and neutron emission spectra show good agreement with the experimental data.
