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  • Author or Editor: U. Wätjen x
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Abstract  

Recently, the Institute for Reference Materials and Measurements (IRMM) has assumed responsibility for organizing regular measurement comparisons among those laboratories which provide radioactivity monitoring data from their country to authorities of the European Commission (EC) under various EC legislation articles. The most recent exercise under this International Comparison Scheme for Radioactivity Environmental Monitoring (ICS-REM) in measuring the 137Cs, 40K and the 90Sr activity concentration in milk powder is presented here. The complete cycle of the comparison is described, including the establishment of reference values traceable to SI units, the demonstration of the homogeneity of the distributed samples, the treatment and measurement of samples in the participating laboratories, and the evaluation of the results.

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Abstract  

Five copper alloys were prepared with modern powder metallurgical processes in the frame of the European project Improvement of Means of Measurement on Archaeological Copper-Alloys for Characterisation and Conservation (IMMACO) and certified for As, Pb, Sn and Zn mass fractions. Similar in their composition to archaeological bronze alloys, these Certified Reference Materials (CRMs) are to be used for calibration of XRF instruments for characterization of archaeological samples either in the laboratory or in the field. This paper presents and compares the successful contribution of our non-destructive analytical methods (k 0-NAA and PIXE) to the IMMACO project and to the certification of the five reference materials.

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Abstract  

Three new synthetic multi-element standards (SMELS) were developed for testing the performance of the k 0-standardization neutron activation analysis (k 0-NAA) method when implemented in a laboratory. SMELS consist of a phenol-formaldehyde polymer matrix spiked with different groups of elements according to the half-lives of the formed radionuclides. They are classified as Type I for short-, Type II for medium- and Type III for long-lived radionuclides. This article presents the preparation of SMELS including different aspects such as choice of the matrix and spiking elements, chemical compounds, target concentrations, purity of the matrix and spiking procedure and the homogeneity study for all the spiked elements in order to demonstrate the quality of the produced materials.

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Abstract  

The paper presents the results of radiological investigation of several mushroom samples collected in the fall of 2004 in different parts of Europe. The work was performed in order to support decision making to develop and produce a certified reference material for quality assurance of radionuclide measurements in environmental samples. The levels of 137Cs in mushrooms varied widely ranging from 0.6 to 4300 Bq/kg on dry mass basis, while those of natural 40K were relatively constant. In one sample 60Co of unknown origin was detected (25±2 Bq/kg dry mass), while 90Sr concentrations were usually below the detection limit (<150 mBq/kg dry mass).

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Abstract  

In 2007/2008 the Institute for Reference Materials and Measurements (IRMM) organised an interlaboratory comparison (ILC) on the determination of 226Ra, 228Ra, 234U and 238U activity concentrations in mineral water. This paper describes the determination of the reference values for the activity concentrations of 234U and 238U by radiochemical separation and α-particle spectrometry performed at two independent laboratories. The experimental uncertainty of the reference values is discussed in detail.

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