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ABSTRACT: An analytical system is suggested to separate a number of elements of the Periodic Table in a hydrogen or oxygen stream at temperatures up to 1400 °C. High temperature chemical filters are used to separate volatile products. The approach has demonstrated its efficiency in a number of examples of carrier-free isotope production from targets irradiated at an accelerator: 109 Cd from In; 22 Na from Al; 72 Se from GaAs; 188 Pt, 183 Re, 185 Os and 201 Tl from Pb or Bi; separation of Po from Pb and Bi, etc. Another application of high temperature chemical sublimation of elements and oxides was realized in activation analysis of noble metals in various ores and samples.
Journal of Radioanalytical and Nuclear Chemistry 12/2004; 263(1):59-64. · 1.52 Impact Factor
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ABSTRACT: In the analysis of biological samples with sub ng/g uranium concentrations, pre-concentration has been shown to improve the detection limit for the determination of uranium. Recovery corrected kinetic phosphorescence analysis (KPA) combines pre-concentration and separation of uranium by anion-exchange from human tissues dissolved in 6M HCl, with the radiochemical yield determined by alpha-spectrometry, using 232 U as a tracer. Total uranium is determined by KPA after correction for chemical recovery. Twenty-one randomly selected dissolved tissue samples from the United States Transuranium and Uranium Registries (USTUR) Case 0242 were chosen for comparative analyses. The set of samples included dissolved bone and soft tissues. Uranium concentrations for seven of the samples had not been previously reported. Direct KPA could not be used to determine uranium concentrations of five unreported tissues. Three of these tissues had uranium concentrations at or below the KPA L Q value of 0.028 ng/ml and two tissues had known matrix interferences. All seven of the unreported tissues were successfully analyzed by recovery corrected KPA; concentrations ranged from 9 to 1380 ng per tissue, including those that could not be analyzed by direct KPA due to matrix problems. Recovery corrected KPA gives results similar to direct KPA where matrix interferences and low detection limits are not encountered. A comparison of the direct method of KPA versus recovery corrected KPA shows marked improvement for the determination of uranium in samples that heretofore either uranium was not detected or the sample had to be drastically diluted to minimize matrix effects in order to measure uranium.
Journal of Radioanalytical and Nuclear Chemistry 12/2004; 263(2):295-300. · 1.52 Impact Factor
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ABSTRACT: The present study evaluated the feasibility of direct measurement of alpha emitting radionuclides in liquids using passivated ion implanted planar silicon (PIPS) diode detectors. The performance characteristics and durability of PIPS diode detectors enabled direct detection of alpha particles from liquid samples by placing the diode detector in close proximity to the liquid sample. Factors affecting the sensitivity and accuracy of direct detection of alpha-emitters in solution and interferences of beta/gamma emitters have been examined. Direct assay of liquid samples using PIPS diode detectors can enable rapid and straightforward detection methodologies suitable for process control applications.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
