EFFECT OF CU AS МINORITY АLLOYING ЕLEMENT ON GLASS FORMING ABILITY AND CRYSTALLIZATION BEHAVIOR OF RAPIDLY SOLIDIFIED AL-SI-NI RIBBONS

The influence of copper as a minority alloying element in the process of rapid solidification of Al-Si-Ni ribbons produced by Chill Block Melt Spinning (CBMS) was investigated. XRD and TEM analyses proved a completely amorphous structure of the alloys Al74Ni16Si10 and (Al74Ni16Si10)98Cu2. The crystallization behaviour of these alloys was studied by DSC analysis. It was found that the crystallization of the amorphous alloys (Al74Ni16Si10)100-xCux, x=0, 2 runs in two steps. The temperatures Tx1 and Tx2 of each of the crystallization steps were determined. It was proven that the addition of 2 at. % copper does not significantly change Tx temperatures. The temperature difference ΔTx was calculated and it showed that more thermally stable is the copper containing alloy. Crystalline analogues of the amorphous alloys were obtained by annealing of the melt-spun amorphous ribbons at a temperature which exceeded by 170°C the onset crystallization temperature. The type and size of separated crystalline phases were determined by XRD. It was found that the addition of 2 at. % Cu to Al74Ni16Si10 alloy causes a separation of new phases - Cu3.8Ni and (Al, Cu)Ni3 and 54%, 24% and 7% size increase of the phases Al, Al3Ni, NiSi2 respectively

Evaluation of EC Measurement Comparison for 137Cs, 40K and 90Sr in Milk Powder

This report describes the full life cycle of the measurement comparison of 137Cs, 40K and 90Sr in milk powder among 60 European laboratories monitoring radioactivity in food and the environment. An available IAEA reference material was re-processed at IRMM into suitable intercomparison samples and the homogeneity of the distributed samples together with other quality parameters was determined. Reference values of the three radionuclides under study in this intercomparison were determined at IRMM using tracer techniques and standardised radionuclide solutions and are thus traceable to the SI units. The sample preparation and measurement processes applied in the participating laboratories are described and the results of the intercomparison are presented and discussed in detail. Whereas, in general, the measurement results for 137Cs and 40K show good agreement with the reference value, the results of this comparison point at problems of 90Sr determination in about one third of the laboratories. The corresponding participants should investigate and revise their analytical methods, next to many laboratories needing to improve their estimation of measurement uncertainty.JRC.D.4-Isotope measurement

Evaluation of EC Comparison on the Determination of 226Ra, 228Ra, 234U and 238U in Mineral Waters

This report describes all details of the comparison for the determination of 226Ra, 228Ra, 234U and 238U in mineral waters among 45 European laboratories monitoring radioactivity in food and the environment. Three commercially available mineral waters were provided as comparison samples. Reference values of the four radionuclides under study in this comparison were determined in collaborative work of IRMM and the Bundesamt für Strahlenschutz (BfS), using tracer techniques and standardised radionuclide solutions. The reference values are thus traceable to the SI units. The sample preparation and measurement processes applied in the participating laboratories are described and the results of the comparison are presented and discussed in detail. Whereas, in general, the measurement results for the uranium isotopes show a relatively favourable agreement with the reference value, the results of this comparison point at severe problems of 226Ra and 228Ra determination in about one fourth and more than one third of the laboratories, respectively. For radium, 19 results corresponding to 14 % of all are even off by a factor of two or more. By comparison, for uranium, this number amounts to 6 % (9 results out of 150). Nevertheless, also for the determination of uranium, 14 % to 23 % of the laboratories report results not compliant with the En evaluation criterion. The corresponding participants are urgently requested to investigate and revise their analytical methods.JRC.D.4-Nuclear physic

Uncertainty Budget for 226 Ra Activity Concentration in Water by Alpha Spectrometry

Abstract Alpha-particle spectrometry is the most frequently used technique for the activity determination of alpha emitters, such as radium, uranium, plutonium, americium and thorium in environmental samples. In this paper an extensive uncertainty budget is presented for a typical alpha-particle spectrometry measurement of the 226 Ra activity concentration in drinking water. The most influential parameters contributing to the uncertainty are investigated. The set-up used is a common alpha-spectrometry system for environmental samples using PIPS detectors. In particular, the influence of geometrical parameters as well as the activity distribution in the measured sources on the solid angle is scrutinised

The certification of the activity concentration of the radionuclides 137Cs, 90Sr and 40K in wild berries: IRMM-426

This report describes the production of CRM IRMM-426, a dried bilberry material certified for the radionuclide activity concentrations of 137Cs, 90Sr and 40K. The material was produced following ISO Guide 34:2009. Bilberry samples were collected in a woodland region of so-called “strontium hot spots” close to the Chernobyl reactor site. The samples were air-dried at the sampling site before transport to IRMM, where the raw material was oven-dried, cryo-milled, sieved, homogenised and bottled. The bottled material was sterilised by gamma-irradiation. Between-unit homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006. The material was characterised by an intercomparison among laboratories of demonstrated competence and adhering to ISO/IEC 17025. Technically invalid results were removed but no outlier was eliminated on statistical grounds only. Uncertainties of the certified values were calculated in compliance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible inhomogeneity and instability and to characterisation. The material is intended for the assessment of method performance and quality control. As any reference material, it can also be used for control charts or validation studies. The CRM is available in amber glass jars containing about 100 g of dried bilberry powder. The minimum amount of sample to be used for analysis is 50 g for 90Sr and 18 g for 137Cs and 40K.JRC.D.2-Standards for Innovation and sustainable Developmen

A Practical Procedure for Assigning a Reference Value and Uncertainty in the Frame of an Interlaboratory Comparison

A method is suggested for the calculation of a reference value and its uncertainty to be used in the frame of an interlaboratory comparison (ILC). It is assumed that the reference value of the measurand is determined independently from the ILC round. It is derived from a limited set of measurement results obtained from one or several expert laboratories.JRC.D.4-Isotope measurement

Measurement Comparisons of Radioactivity among European Monitoring Laboratories for the Environment and Food Stuff

For more than 15 years, EU laboratories monitoring environmental radioactivity have been obliged to participate in measurement comparisons organised by the European Commission. After a short review of comparisons conducted during the 1990s, the approach of IRMM organising these comparisons since 2003 is presented. It relies on the provision of comparison samples with reference values traceable to the SIR. The results of the most recent comparison, the determination of 40K, 90Sr and 137Cs in milk powder, are presented. The influence of repetitive participation in measurement comparisons on laboratory performance is studied on the basis of data from more than 20 laboratories having participated in several exercises during the last 15 years.JRC.D.4-Isotope measurement

European Measurement Comparison of 137Cs, 40K and 90Sr in Milk Powder

Recently, IRMM has assumed responsibility for organising regular measurement comparisons among those laboratories which provide radioactivity monitoring data from their country to authorities of the European Commission (EC) under obligations of the EURATOM Treaty. The most recent exercise under this International Comparison Scheme for Radioactivity Environmental Monitoring (ICS-REM) is presented here. The exercise was designed to evaluate the performance of the participating laboratories in measuring Cs-137, K-40 and Sr-90 activity in milk powder. The whole cycle of the intercomparison is described, including the establishment of traceable reference values, demonstration of the homogeneity of the distributed samples, treatment and measurement of samples in the participating laboratories, and evaluation of the results.JRC.D.4-Isotope measurement

Visualisation of Interlaboratory Comparison Results in PomPlots

In this work a novel graphical method is applied to the presentation of intercomparison results. This is demonstrated with the results of a recent intercomparison in measuring the 137Cs, 40K and 90Sr activity concentration in milk powder. The 'PomPlot', an intuitive graphical method, is used for producing a summary overview of the participants' results of a common measurand. The 'PomPlot' displays (relative) deviations of individual results from the reference value on the horizontal axis and (relative) uncertainties on the vertical axis.JRC.D.4-Isotope measurement

Uncertainty Budget for 226Ra Activity Concentration in Water by Alpha Spectrometry

Alpha-particle spectrometry is the most frequently used technique for the activity determination of alpha emitters, such as radium, uranium, plutonium, americium and thorium in environmental samples. In this paper an extensive uncertainty budget is presented for a typical alpha-particle spectrometry measurement of the 226Ra activity concentration in drinking water. The most influential parameters contributing to the uncertainty are investigated. The set-up used is a common alpha-spectrometry system for environmental samples using PIPS detectors. In particular, the influence of geometrical parameters as well as the activity distribution in the measured sources on the solid angle is scrutinised.JRC.D.4-Isotope measurement