The distribution of natural radionuclides K, Ac, and Ra on Romanian Territory: a radiometric study.

To estimate the radiation hazard due to the natural terrestrial radioactivity, 598 samples of soil covering the entire Romanian territory were collected and analyzed for the distribution of natural radionuclides K, Ac, and Ra. The ultra-low background Slanic-Prahova underground laboratory was used to determine the gamma-ray-specific activity of these radioactive isotopes with an uncertainty between 5 and 20%. All these data permitted to establishing a set of 2D maps illustrating the distribution of specific activity of each radionuclide as well as of the resulting air dose rate, all of them illustrating an heterogeneous distribution, increased values being displaced on the western and south-western territory.

Cs distribution on the territory of Romania 30 years after Chernobyl accident.

To estimate the contribution of Chernobyl Cs contamination, in 1993 and especially 2016, its total inventory was determined by gamma-ray high-resolution spectroscopy in 62 and respectively 747 soil samples covering the entire Romanian territory. This permitted to estimate the Cs inventory as varying between 0.4 and 187 as well as between 0.

Determining the probability of locating peaks using computerized peak-location methods in gamma-ray spectra as a function of the relative peak-area uncertainty.

The probabilities of locating peaks with a high relative peak-area uncertainty were determined empirically with nine types of peak-location software used in laboratories engaged in gamma-ray spectrometry measurements. It was found that it is not possible to locate peaks with a probability of 0.95, when they have a relative peak-area uncertainty in excess of 50%.

Muography applications developed by IFIN-HH.

Cosmic-ray muons have been studied at IFIN-HH for more than 20 years. Starting as fundamental physics research, the muon flux measurements bring new directions of study regarding muography. Two new directions have been recently developed: underground muon scanning of old mining sites in order to detect the possible presence of unknown cavities and underwater scanning of ships in commercial harbours in order to prevent the illegal traffic of radioactive materials.

Systematic influences on the areas of peaks in gamma-ray spectra that have a large statistical uncertainty.

A method is presented for calculating the expected number of counts in peaks that have a large relative peak-area uncertainty and appear in measured gamma-ray spectra. The method was applied to calculations of the correction factors for peaks occurring in the spectra of radon daughters. It was shown that the factors used for correcting the calculated peak areas to their expected values decrease with an increasing relative peak-area uncertainty.