REFERENCE SURFACE FOR IN SITU GAMMA SPECTROMETRY.

Chemical laboratories of the Fire Rescue Service of the Czech Republic are part of the radiation monitoring network and participate in the radiation situation monitoring in the Czech Republic. Measurements in situ are crucial for monitoring the radiation situation in emergencies associated with the deposition of radioactive substances on a large area. Those data can be used for estimating a possible dose obtained either by staying in a contaminated area or by consumption of food produced in the area. For correct setting of device parameters (e.g. efficiency calibration), standard samples should be measured regularly. Unlike in laboratory, verification in field conditions is difficult. Therefore, a search for suitable reference areas containing a higher amount of 137Cs homogeneously dispersed after the fall of a radioactive cloud passing through our territory following the Chernobyl accident was conducted. Small airports in the East Bohemia regions were identified as suitable candidates.