Cosmogenic beryllium-7 in the near-ground air of Ukraine

Abstract

The 7Be isotope is of exclusively natural origin. This radionuclide attaches to the submicron aerosols, so 7Be can be used as a marker in the search for patterns of air mass movements. Studies of natural cyclic variations and sporadic increases in volume activity of 7Be are needed to identify of various sources of total radioactivity of near-ground air. Using the measurement data of radionuclide stations located in four regions of Ukraine within 48–51°N and 25–30°E, seasonal and annual variations in the volume activity of beryllium-7 in surface air were studied. We used both published data for 2005-2019 and new measurement results of the Main Center for Special Control in Ukraine (https://gcsk.gov.ua/), carried out in 2017–2020. This material confirms the seasonal changes in the volume activity of beryllium-7, found earlier for latitudes 45–55°N, with a maximum in April-August and a minimum in November- February. Comparison of measurements in Ukraine with the data of radionuclide monitoring of neighboring countries made it possible to choose the most reliable row of average annual values from 2005 to 2011, which was obtained from measurements in the Chernobyl zone. This data correlates with the flux of the neutron component of cosmic rays and with the height of the equipotential surface of 200 mbar.