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Abstract  

A certified reference material (CRM) for radionuclides in seawater, IAEA-381 (Irish Sea Water), is described and the results of certification are presented. The material has been certified for nine radionuclides (40K, 90Sr, 137Cs, 237Np, 238Pu, 239Pu,240Pu, 239,240Pu and 241Am). Information on massic activities with the corresponding 95% confidence intervals are given for eight radionuclides (3H, 125Sb, 234U, 235U, 236U, 238U, 241Pu and 244Cm). Less reported radionuclides include 60Co, 99Tc, and 242Pu. The CRM may be used for quality assurance/quality control of the analysis of radionuclides in environmental water samples, for the development and validation of analytical methods and for training purposes. The material is available from the IAEA in 5 kg units.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Pham, M. Betti, P. Povinec, M. Benmansour, V. Bünger, J. Drefvelin, C. Engeler, J. Flemal, C. Gascó, J. Guillevic, R. Gurriaran, M. Groening, J. Happel, J. Herrmann, S. Klemola, M. Kloster, G. Kanisch, K. Leonard, S. Long, S. Nielsen, J.-S. Oh, P. Rieth, I. Östergren, H. Pettersson, N. Pinhao, L. Pujol, K. Sato, J. Schikowski, Z. Varga, V. Vartti, and J. Zheng

Abstract  

A new certified reference material (CRM) for radionuclides in sea water from the Irish sea (IAEA-443) is described and the results of the certification process are presented. Ten radionuclides (3H, 40K, 90Sr, 137Cs, 234U, 235U, 238U, 238Pu, 239+240Pu and 241Am) have been certified, and information values on massic activities with 95% confidence intervals are given for four radionuclides (230Th, 232Th, 239Pu and 240Pu). Results for less frequently reported radionuclides (99Tc, 228Th, 237Np and 241Pu) are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in water samples, for the development and validation of analytical methods and for training purposes. The material is available in 5 L units from IAEA (http://nucleus.iaea.org/rpst/index.htm).

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Abstract  

The instrumental neutron activation analysis technique (INAA) was used for homogeneity tests and certification analyses of coal fly ash reference materials ENO, ECH, and EOP prepared at the Institute of Radioecology and Nuclear Techniques (IRANT), Koice, Czechoslovakia. Quantitative estimation of a degree of inhomogeneity was suggested. The relative standard deviations due to inhomogeneity were found to be <1% for macroconstituents and <3% for minor and trace elements for sample weights about 25 mg. The results of determination of the elements Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Ga, Hf, In, K, La, Mn, Na, Nd, Ni, Rb, Sb, Sc, Sm, Sr, Ta, Th, Ti, U, V, W, and Zn were compared with the IRANT certified or information values. NBS SRM 1633a Trace Elements in Coal Fly Ash was also analyzed as a control sample and the results for the above elements were compared with the NBS certified, information or literature available values. From these comparisons, inference was made on the quality of the IRANT specified values for the element contents.

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Abstract  

In order to calibrate a gamma-ray spectrometer for radioactivity measurements in environmental samples, it is essential to use standard radioactive sources in the appropriate geometrical configuration. However, the lack of standard sample due to any reason would necessitate the use of reference materials as reliable alternative. They often appear in many matrices and densities. Accordingly, special attention should be drawn towards optimizing the calibration. This work studies the errors encountered because of the attenuation process due to the density difference of the samples (including reference samples) aliquots with identical matrix contents. The highest effect was noticed in the lower energy regions. This study suggests that even for the reference samples with the same matrix, it is necessary to set a recommended density for the measurement process to avoid the errors due to the attenuation. If this is not practically possible it is recommended that attenuation correction due to matrix contents followed by another correction due to density correction would be a reliable approach to reach an optimum calibrating condition.

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Abstract  

In order to determine the elemental concentrations of three new soil standard reference materials SRMs 2709, 2710 and 2711 from the National Institute of Standards and Technology (NIST), a comparative study of different medium-lived neutron activation analysis methods was carefully performed. Three irradiation conditions (1-hour thermal, 1-hour epithermal and 5-minute epithermal) and two counting modes (normal and Compton suppression) have been evaluated for following ten elements: As, Au, Cd, Ga, K, La, Mo, Sb, Sm, and W. The results show that the method of 5-minute epithermal and a 1-day decay is the optimum way to analyze Ga, while the addition of the Compton suppression is very beneficial for the determination of K. Using the Compton suppression system in conjunction with the 1-hour epithermal and a 1-week decay, is ideal to determine Au, Cd, Mo and W, while routine 1-hour thermal and a 1-week decay, is adequate to determine As, Sb, Sm and La in concentrations found in soil.

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Summary  

Elemental concentrations of twelve geochemical reference materials of ores and mineralized rocks were determined including some for which there were few previously published data. Reference materials CHR-Bkg, CHR-Pt, CCU-1c, NBM-1a, NBM-2a, NBM-4a, NBM-6a, NBM-6b, PM-S, UMT-1, WMG-1, and WMS-1 were analyzed for 34 elements by instrumental neutron activation. To our knowledge, the analytical results in this paper are among the first published for five reference materials from the Nevada Bureau of Mines and Geology. Reliable results for Au and Ir down to concentrations of a few ng.g-1were obtained without preconcentration.

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Abstract  

A suite of natural matrix reference materials (RMs) were used to assess the quality of analytical results obtained by k 0-instrumental neutron activation analysis (k 0-INAA) at the Joef Stefan Institute (IJS). Five certified reference materials (CRMs) from the Institute for Reference Materials and Measurements (IRMM), two standard reference materials (SRMs) from the National Institute of Standards and Technology (NIST), three RMs from the International Atomic Energy Agency (IAEA) and one RM from IJS were analyzed. Altogether, results for twenty-four elements in inorganic matrices and twenty-nine elements in organic matrices, obtained by k 0-INAA, were compared to certified values. Results obtained show good agreement with certified or assigned values except for Fe, La, Nd, Sm and U in inorganic matrices, and Ag, Al and Cr in organic matrices.

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Introduction Reference materials of known properties are commonly used to calibrate, verify, or validate the performance of test instruments or methods. In dynamic mechanical analysis, spring steel is commonly used to calibrate

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Abstract  

Instrumental neutron activation analysis was applied to determine La, Ce, Nd, Sm, Eu, Tb, Yb, Lu and Sc in two biological reference materials: NIST 1575 Pine Needles and BCR-CRM 101 Spruce Needles. The purpose was to contribute to the reference data for these two reference materials. The results were obtained with a good precision (relative standard deviations less than 15%). For the Pine Needles reference material there are already some proposed values and our results showed, in general, a good agreement with the data published. The contribution of uranium fission products to La, Ce, Nd and Sm was evaluated and considered in the determination of these elements. Interferences in the determination of rare earth elements in biological materials are also discussed.

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Abstract  

The comparator instrumental neutron activation analysis (INAA) method was used for certification of arsenic in Korea Research Institute of Standards and Science (KRISS) reference materials 108-04-001 (Oyster Tissue). The certified value was determined by analyzing one sample of approximately 0.15 g from ten bottles selected by random sampling. Potentially significant sources of uncertainty were taken into consideration using the guideline given by ISO. A complete evaluation of all sources of uncertainty yielded an expanded uncertainty for the mean value of this reference material of 4.7% at approximately 95% level of confidence.

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