Determination of 7Be concentration in Tehran city using high volume air sampler and HPGe detector

In this research, air samples were collected at an air flow rate of 300 m3/h to 900 m3/h. These samples were collected during more than two months (Nov 2019-Jan 2020). After the decay of short-lived radionuclides, the samples were formed as a disc to prepare for measurement. Then, these discs were evaluated by two HPGe detectors with relative efficiencies of 40% and 70%. A prototype of a standard high volume air filter was proposed and constructed by a novel method, which provides a symmetric distribution of radionuclides and efficiency calibration curve was obtained for two HPGe detectors. This standard filter was solved the problem of the asymmetry and inhomogeneous distribution of radionuclides in standard air samples. 7Be concentrations were assessed in the collected samples. The average concentration of 7Be was measured as 3.80±0.46 mBq/m3.