Concentrations of ⁷Be in the Atmosphere in Yavne during 2003-2017

The cosmogenic radionuclide ⁷Be (T_1/2 = 53 d) is continually produced in the upper atmosphere (stratosphere and troposphere) from spallation of oxygen and nitrogen by cosmic radiation (protons and neutrons). The product molecules attach to aerosols, diffuse into lower atmospheric layers and then deposit to the ground (e.g., by precipitation). The concentration of ⁷Be in the air at ground level depends on several parameters, such as height from surface and temperature. Knowledge on the concentration of ⁷Be is important for research related to environmental sciences (e.g., transport of pollution in the atmosphere). Thus, the concentrations of ⁷Be are continuously monitored in multiple locations worldwide.

Monitoring of radionuclides in the air is continually performed at the Soreq Nuclear Research Center, located at sea level. In this work, we describe the ⁷Be measurements performed from 2003 to 2017. Air sampling was carried out in the following manner: 3.5 days of sampling, 1 day of waiting time and 1 day of measurement. Air sampling was performed using a high volume sampler positioned 1 m aboveground. The filter was later compressed and measured using a high-purity germanium detector. Activity concentration was quantified based on the 478 keV emission line of ⁷Be. Trends of the ⁷Be air concentration will be presented, including its correlation to seasonal changes in Israel, and compared to measurements performed in several locations worldwide.