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- Author or Editor: M. Herranz x
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Abstract
Different approaches are found in the literature to compute the characteristics limits used to decide whether an activity measurement result for a radionuclide is significantly above the background level for the analyte in the sample. Comparing the different working expressions of the characteristic limits (critical level and detection limit) that can be used by any measurement laboratory; this paper shows that they are similar under the routine conditions of a majority of radioactivity measurement laboratories.
Abstract
Time series analysis techniques have been applied to the study of the 7Be activity concentration in air, which was obtained by weekly collecting aerosols in filters in the north of Spain, and measuring them by gamma ray spectrometry. Between 2001 and 2009, a trend pattern is found. The cyclical component of this series is clearly influenced by the solar cycle (11 years period). Two kinds of seasonality were found in the time series: annual periodicity and variations with seasons of the year. The irregular component has also been studied but its contribution has been insignificant; one of its possible causes, rainfall, has been analysed and the conclusion is that the atmospheric concentration of 7Be is unaffected by rainfall. The contribution of 7Be presence in air to the total effective dose rate in air has also been studied, resulting negligible.
