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Brno, Czech Republic

Olsovcova V.,Czech Metrology Institute
Applied Radiation and Isotopes | Year: 2010

The response of radionuclide calibrators for radionuclides with high abundances of high energy X-rays is very sensitive to changes in the source geometry. The magnitude of this effect was explored for Bqmetr (Konsorcium BQM, CR) calibrators with 123I, 111In and 153Sm in several vial and syringe geometries. Dependencies of chamber responses on solution volume and container position were calculated using MCNP transport code. The possibility of usage of an additional copper filter to reduce chamber sensitivity was studied and found to be suitable. © 2009 Elsevier Ltd.

Havelka M.,Czech Metrology Institute
Applied Radiation and Isotopes | Year: 2012

Since 2000 the software coincidence counting (SCC) system has been used for activity standardisation of about 15 radionuclides. Their activities were determined by the efficiency extrapolation method applied to 4π (PC)-γ coincidence. Some standardisations, mainly standardisations of EC-Β+ radionuclides, required optimal setting of coincidence parameters, for which new procedures based on "the coincidence to total PC count ratios", "a multiple gamma window combined from subwindows fractions" and "a source test for PC detection efficiency " were introduced. The paper summarises the development of SCC system related to findings from detailed analyses of recorded data. These findings are not practically achievable by a conventional approach. © 2012 Elsevier Ltd.

The measured oxygen refractive index formulas are still not sufficient for precise metrological applications. Thus, a new dispersion formula for the molecular oxygen refractive index at standard conditions is derived. The agreement of the standard air refractive index obtained from indices of its components with recent dry air refractive index formulas is within a few billionths. © 2011 Optical Society of America.

Zachovalova V.N.,Czech Metrology Institute
IEEE Transactions on Instrumentation and Measurement | Year: 2014

This paper describes mathematical modeling of cage-type ac current shunts. A calculable model was developed using lumped circuit elements. The transimpedance, ac-dc difference, and the phase angle error of a shunt can be derived from the model. An uncertainty analysis of the model was done by means of Monte Carlo methods. Comparison of the calculated and measured values shows an agreement better than 6 μΩ/Ω in the ac-dc difference and 110 μrad in the phase angle error at frequencies up to 100 kHz. © 2013 IEEE.

Necas D.,Masaryk University | Klapetek P.,Czech Metrology Institute | Klapetek P.,Brno University of Technology
Central European Journal of Physics | Year: 2012

In this article, we review special features of Gwyddion-a modular, multiplatform, open-source software for scanning probe microscopy data processing, which is available at http://gwyddion. net/. We describe its architecture with emphasis on modularity and easy integration of the provided algorithms into other software. Special functionalities, such as data processing from non-rectangular areas, grain and particle analysis, and metrology support are discussed as well. It is shown that on the basis of open-source software development, a fully functional software package can be created that covers the needs of a large part of the scanning probe microscopy user community. © 2011 © Versita Warsaw and Springer-Verlag Wien.

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