Environmental radiation monitoring

 

Environmental radioactivity is a combination of different components such as environmental gamma radiation, radioactivity in construction material of detectors, radio impurities in the shield, cosmic rays, radon gas and man-made radioactivity. The purpose of this research is to collected data for subsequent studies such as soil, water and air on plants, animals, foods for humans in Vietnam, from the irradiation center, from hospitals in radiation therapy, and especially from future nuclear power plants.

 

The research in this field includes network of monitors, sample collection, sample analysis from the laboratory, data estimation... Equipments used in the analysis such as low background gamma spectroscopy include HPGe detectors, alpha spectroscopy, total beta alpha spectroscopy, dose rate meter – inspector.

 

Nowadays, gamma spectrometer using HPGe detector becomes important and essential for the measurement of radioactivity in many laboratories in the world. Therefore, research, investigation of characteristics of spectroscopy plays an important role. Optimizing detector geometry and using optimized parameters in Monte Carlo simulations allows to calculate efficiency. The reliability of the method is evaluated from a comparison simulated and measured efficiency.

 

Radon isotopes, both radon 222Rn and thoron 220Rn, are present in air as active gases emanating from traces of 238U and 232Th in building construction materials and/or local soils and rock. Neither of these is particularly well endowed with gamma-ray emissions but their progeny are. These can be absorbed on dust particles and surfaces within the detector enclosure and give rise to characteristic peaks of 214Pb, 214Bi and 210Pb, (from the 238U series) and 212Pb, 212Bi and 208Tl (in the 232Th series) in the background.