Radon transport mechanisms in soils were studied to determine the dominant transport mechanism for Delaware county soils. In modeling the soil, it was assumed that is was homogenous and moisture-free. Two transport mechanisms were investigated, the transport of radon in the soil by molecular diffusion (assumed to be governed by Fick's law) and transport by pressure-induced flow or convection (assumed to be governed by Darcy's law). Following the previous work of W. E. Clements, a general transport equation was described which incorporated both diffusion and convection. In steady-state conditions, a closed-form solution was obtained for the concentration of radon in the soil interstices as a function of depth. Similarly, solutions were examined for transport by diffusion alone. Representative soil parameters were assigned and the diffusion fraction (the ratio of concentration due to diffusion to the concentration due to both diffusion and convection) was calculated. Referring to the work of A. B. Tanner, a radon availability number (RAN) was determined for the soils; the RAN value was a measure of the activity of radon per unit area. Analyses were also performed to determine the significance of pressure variations on calculated diffusion fractions and RAN values. For 99% of the acreage in Delaware county, the diffusion fraction was 0.95 or greater. Therefore, it was concluded that molecular diffusion is the dominant transport mechanism for the soils of Delaware county. / Department of Physics and Astronomy

Measurements of radon in groundwater before, during and after the 1995 Kobe earth-quake in Japan indicated that there might be a correlation between levels of 222Rn ingroundwater and seismological activity. The artEmis project investigates this possibleconnection with the goal of building a network of detectors in seismically active parts ofEurope. The detectors will be placed in groundwater and measure many factors, one ofthem being the radon level by measuring gamma radiation. The original vision for thedetectors also included alpha detection. The obtained data is analyzed with artificialintelligence. This thesis investigates a possible method for alpha detection under water. Specif-ically by seeing if it is possible for radon dissolved in water to diffuse from the water,through silicone tubes and into the air inside of the silicone tubes. There is a possibilityfor alpha detection of the radon decay if the radon gas could get into the air. This wasinvestigated by submerging an air-filled silicone construction in water with high levelsof radon. The level of radon in the water was increased by placing pieces of lightweightconcrete in the water. The construction was removed after a period of time and itsgamma-ray spectrum was measured. A statistically significant increase in radon levelscompared to the background radiation would indicate that diffusion happened. Measurements of the silicone construction with a germanium detector resulted ingamma spectra that were analyzed with a Python program to determine the activity of222Rn over time. Short measurements, around 1 hour long, showed a significant increaseof radon compared to the background. For longer measurements however, around one ortwo days, this effect was no longer apparent. The conclusion is that radon diffused intothe silicone construction, either into the silicone material itself or into the air inside theconstruction, but it comes out again quickly. If the radon diffused into the air inside ofthe silicone, the use of alpha detection to measure radon levels in groundwater is muchless far-fetched than before. Therefore, the artEmis project might be one step closer tousing alpha detection in their detector network.