Radiation monitoring after experimental dirty bomb explosion

Experiments simulating radioactive dirty bomb explosions in an urban area were performed at the National Institute of NBC Protection (SUJCHBO v.v.i.), Czech Republic. A solution containing 99mTc radionuclide was dispersed by an explosion on an open-air model of a square covered with filters. Subsequently, spectra of gamma rays originating in contaminated filters were measured by a hand-held NaI(Tl) spectrometer and laboratory HPGe spectrometers. The ambient dose equivalent rate at measuring vessels was set as well. Self-made standards had been prepared by dripping a defined amount of 99mTc solution uniformly on the filters to set the 99mTc surface contamination of measured samples. The urban area model's radioactive contamination map was set using previously determined filters' locations. The defined amount of 99mTc solution was dripped non-homogenously on some filters to estimate the impact of non-homogenous filters' coverage by radioactive aerosol' particles.