A calibration procedure for beta-gamma coincidence detector-systems using four radioxenon spikes.

The determination of activity concentrations of the CTBT-relevant radioxenon relies on a robust calibration method. A procedure is outlined using four radioxenon spikes for beta-gamma detector-systems with 4π geometry. Detection efficiencies of beta-gamma coincidences in the net count calculation method, including the interference matrix between radioxenon and radon, are determined by three measurement channels: beta singles, gamma singles and beta-gamma coincidences, without reference activity values.

Radioxenon standards used in laboratory inter-comparisons.

Preparation methods for (133)Xe standards of activity concentration and the results of the 2014 (133)Xe laboratory inter-comparison exercise are described. One element of the quality assurance/quality control (QA/QC) program for laboratories of the International Monitoring System (IMS) will be regular inter-comparison exercises. However, until recently, no activity concentration standards for benchmarking were available.

Vertical distribution of radionuclides in soil of a grassland site in Chernobyl exclusion zone.

Five soil profiles from a site about 8 km SE of the Chernobyl NPP were investigated for the vertical distribution of radionuclides. The average (137)Cs-inventory at the site is about 2.6 MBq/m(2) (reference date 1 May 1986).