Radon and thoron investigation
conducted by Natural Radioactivity Laboratory
IFJ PAN, Krakow, Poland


Miroslaw Janik 

Natural Radioactivity Laboratory, Institute of Nuclear Physics, Krakow, Poland 

Radon (radon and thoron) and its short-lived daughters are the most important radioactive 
sources in air and cause about half of the effective dose equivalent of all natural ionizing radiations. 

Natural Radioactivity Laboratory (NRL) has carried out many types of radon investigation, from 
in-situ measurements (radon and thoron concentration in soil gas, radon exhalation rate and soil 
permeability) to radon transport modeling. 

Within scientific cooperation with Vinca Institute of Nuclear Science, Belgrade, Serbia and 
Montenegro, NRL takes part in the field work. This investigation are conducted in Niska Banja spa (in 
Serbia and Montenegro) where extremely high radon (222Rn) concentrations are observed in soil gas 
(> 2000 kBq/m3) as well as very high values of radon exhalation rates (1.5 Bq/m2s). The next control 
measurements and monitoring of radon risk are planned for full recognition and understanding of that 
unusual phenomenon. 

Another part of our research is transport of radon and its moving from ground into the house. 
Radon concentration in house depends on many parameters, such as soil permeability for gases, soil 
porosity, radium concentration in soil and the spatial distribution of these parameters, which should 
be incorporated in the numerical model. The results of soil measurements in houses around Krakow 
agglomeration were compared to radon transport model (TriRAD) output. The difference between 
model and experimental data is in the range 10 - 20%. 

Our current research concentrates on radon exhalation from the ground and its dependence 
on different factors. The measurements are performed on the Radon Study Field which is located at 
the Institute of Nuclear Physics.