DEVELOPMENT OF 222RN IN AIR SECONDARY STANDARD IN THE SLOVAK REPUBLIC.

Slovak Institute of Metrology received in 2016 funding for realisation of a set up of a radon chamber with AlphaGUARD as a secondary standard of 222Rn in air as one part of the project. This secondary standard will serve to provide the traceability for laboratories that deal with 222Rn measurements in environmental samples. This project is a response to the European Union legislation and provides metrological support for the development and implementation of the national radon action plan, which the member states of the European Union are committed to fulfil in accordance with Council Directive 2013/59/Euratom. During development of the radon chamber, the determination of its basic technical parameters, such as the exact determination of the container volume and the area of the inner walls of the radon chamber, many tightness tests of the chamber, the definition of homogeneous radon atmosphere parameters and bilateral comparisons, were realised.

(60)Co in cast steel matrix: A European interlaboratory comparison for the characterisation of new activity standards for calibration of gamma-ray spectrometers in metallurgy.

Two series of activity standards of (60)Co in cast steel matrix, developed for the calibration of gamma-ray spectrometry systems in the metallurgical sector, were characterised using a European interlaboratory comparison among twelve National Metrology Institutes and one international organisation. The first standard, consisting of 14 disc shaped samples, was cast from steel contaminated during production ("originally"), and the second, consisting of 15 similar discs, from artificially-contaminated ("spiked") steel. The reference activity concentrations of (60)Co in the cast steel standards were (1.077±0.019) Bqg(-1) on 1 January 2013 12h00 UT and (1.483±0.022) Bqg(-1) on 1 June 2013 12h00 UT, respectively.

An advanced method of activity determination of large area beta emitting sources.

The presented advanced method of activity determination of large area beta emitting sources is based on a version of efficiency tracing method using a test foil placed between the source and a conventional large area detector. It is shown that the total efficiency of the measuring system may depend on a dimensionless parameter derived from the difference in count rates caused by inserting the test foil while other disturbing effects are mostly reduced or compensated.