No abstract available

[en] The scope of radioanalysis can be enlarged substantially by preconcentration. The minimal concentration factor required depends on the concentration to be determined, the limit of determination of the analytical technique and the maximal acceptable sample-weight. Simultaneously, the preconcentration step may cause a decontamination. In post-irradiation chemistry this is usually the crucial parameter. The present paper proposes the classification of (pre-) concentration techniques by the relation between the concentration-factor X and the decontamination-factor Y. In addition, three other criteria here are used to judge the applicability in combination with the analytical technique chosen. They stem from the minimal representative and the maximal acceptable sample-weights and the maximal acceptable dose-rate. The features of a particular combination of (pre-) concentration and analytical technique can be visualized in an X-Y graph. (author)

[en] Published in summary form only

No abstract available

[en] Published in summary form only

[en] Short communication. A summary of an essay submitted for the Master of Science degree. Leningrad State University, Faculty of Chemistry, Radiochemistry Department, 1985

[en] The purpose of this work is to apply the method of instrumental neutron activation analysis to determine the trace elements in lung samples from autopsy of smoker and non smoker individuals. In this preliminary study, the adequate conditions for analysis and preparation of lung samples had been established. The frozen samples were homogenized, lyophilized and sterllized using ⁶⁰Co source. The samples and the standards were irradiated in the IEA-RI reactor under a thermal neutron flux of 3.7 X 10¹¹ n.cm^-2.s^-1, Au, Br, Co, Cs, Fe, Rb, Sc, Se and Zn were determined. The countings were carried out with a hiperpure (Ge) detector connected to a 4096 channels analyser and a microcomputer. The results obtained indicate a good reproducibility. The accuracy of the method was evaluated analysing reference materials Bowen's Kale from IUPAC and Bovine Liver from NIST. (author)

[en] A single comparator method with its accuracy has been studied for determining multielement by reactor neutron activation analysis. Spectral index at the irradiation position of each sample was determined using two flux monitors of Au and Co, one of which was used as a single comparator. The uncertainties of nuclear data related to the method were investigated for 18 elements and the error of the analytical result due to the uncertainties of nuclear data related is found to be less than 6%. The analytical results of 4 USGS reference samples agree well within 15% deviation with the results evaluated by USGS. (Author)

[en] Trace elements in eleven kinds of coal were determined by thermal neutron activation analysis using the multi-element comparator technique. Coal samples and N.B.S Coal-standard reference material (1632a-Bituminous) were irradiated for 1 min, 10 min and 7 hr at a flux of 10¹² n/cm²-s in the University of London Reactor. The spectra w.re processed using the SAMPO program. The results of different irradiation times were compared to minimize the irradiation time for a particular group of elements. The results were analysed with the CLUSTER ANALYSIS program adapted to PDP11/04 minicomputer to find out the similarity of elemental concentrations for each kind of coal

[en] N.A.A. technique is well known for its sensitivity, precision and selectivity. About 50 elements could be analyzed by this method. The main field application of this technique are in biomedical, forensic science and environmental studies, geology, agriculture and quality control. The main aim of this paper is to provide basic knowledge of this technique and its application in those fields. (author)