Radioactivity and radon emanation fraction of the granites sampled at Misasa and Badgastein

The chemical composition was analyzed and the radioactivity, radon exhalation rate and emanation fraction were measured to investigate the characteristics of the granites sampled at Misasa and Badgastein, world famous for radon therapy. The Misasa granite was probably composed of quartz, albite and microcline. The Badgastein granite was probably composed of quartz and muscovite. The radon exhalation rates and emanation fractions of the Misasa granite were much higher than those of the Badgastein granite, regardless of the Ra-226 activity concentrations

Radon and Thoron Exhalation Rates From Surface Soil of Bangka - Belitung Islands, Indonesia

DOI:10.17014/ijog.2.1.35-42Radon and thoron exhalation rate from soil is one of the most important factors that can influence the radioactivity level in the environment. Radon and thoron gases are produced by the decay of the radioactive elements those are radium and thorium in the soil, where its concentration depends on the soil conditions and the local geological background. In this paper, the results of radon and thoron exhalation rate measurements from surface soil of Bangka Belitung Islands at thirty six measurement sites are presented. Exhalation rates of radon and thoron were measured by using an accumulation chamber equipped with a solid-state alpha particle detector. Furthermore, the correlations between radon and thoron exhalation rates with their parent nuclide (226Ra and 232Th) concentrations in collected soil samples from the same locations were also evaluated. The result of the measurement shows that mostly the distribution of radon and thoron is similar to 226Ra and 232Th, eventhough it was not a good correlation between radon and thoron exhalation rate with their parent activity concentrations (226Ra and 232Th) due to the environmental factors that can influence the radon and thoron mobilities in the soil. In comparison to a world average, Bangka Belitung Islands have the 222Rn and 220Rn exhalation rates higher than the world average value for the regions with normal background radiation

Real-time setup to measure radon emission during rock deformation. Implications for geochemical surveillance

Laboratory experiments can represent a valid approach to unravel the complex interplay between the geochemical behaviour of radon and rock deformation mechanisms. In light of this, we present a new real-time experimental setup for analysing in continuum the alpha-emitting 222Rn and 220Rn daughters over variable stress–strain regimes. The most innovative segment of this setup consists of the radon accumulation chamber obtained from a tough and durable material that can host large cylindrical rock samples. The accumulation chamber is connected, in a closed-loop configuration, to a gas-drying unit and to a RAD7 radon monitor. A recirculating pump moves the gas from the rock sample to a solid-state detector for alpha counting of radon and thoron progeny. The measured radon signal is enhanced by surrounding the accumulation chamber with a digitally controlled heating belt. As the temperature is increased, the number of effective collisions of radon atoms increases favouring the diffusion of radon through the material and reducing the analytical uncertainty. The accumulation chamber containing the sample is then placed into a uniaxial testing apparatus where the axial deformation is measured throughout a linear variable displacement transducer. A dedicated software allows obtaining a variety of stress–strain regimes from fast deformation rates to long-term creep tests. Experiments conducted with this new real-time setup have important ramifications for the interpretation of geochemical anomalies recorded prior to volcanic eruptions or earthquakes

EXPERIMENTAL TECHNIQUE TO MEASURE THORON GENERATION RATE OF BUILDING MATERIAL SAMPLES USING RAD7 DETECTOR

Thoron (220Rn) is the second most abundant radon isotope in our living environment. In some dwellings it is present in significant amount which calls for its identification and remediation. Indoor thoron originates mainly from building materials. In this work we have developed and tested an experimental technique to measure thoron generation rate in building material samples using RAD7 radon-thoron detector. The mathematical model of the measurement technique provides the thoron concentration response of RAD7 as a function of the sample thickness. For experimental validation of the technique an adobe building material sample was selected for measuring the thoron concentration at nineteen different sample thicknesses. Fitting the parameters of the model to the measurement results, both the generation rate and the diffusion length of thoron was estimated. We have also determined the optimal sample thickness for estimating the thoron generation rate from a single measurement

Difusi Gas Radon dari dalam Tanah di Daerah Bengkulu

The aim of this research is to achieve a rough estimation of the radon diffusion coefficient from soil in Bengkulu. The samples were taken from 28 points of different area in Bengkulu. We used a GM tube and LR-115-II detectors to detect the radon concentration. It is found that the average of radon concentration is 136 Bq/m3. While, on the other hand the average of radon diffusion coefficient of soil in­crease lenearly with increase of soil depth. We also found that radon exhalation rate from ground surface is 0.88 mBq/m2/s up to 1.51 mBq/m2/s

The imprint of thermally induced devolatilization phenomena on radon signal. Implications for the geochemical survey in volcanic areas

Thermal gradients due to magma dynamics in active volcanic areas may affect the emanating power of the substrate and the background level of radon signal. This is particularly effective in subvolcanic substrates where intense hydrothermal alteration and/or weathering processes generally form hydrous minerals, such as zeolites able to store and release great amounts of H2O (up to ∼25 wt.%) at relative low temperatures. To better understand the role played by thermally induced devolatilization reactions on the radon signal, a new experimental setup has been developed for measuring in real time the radon emission from a zeolitized volcanic tuff. Progressive dehydration phenomena with increasing temperature produce radon emissions two orders of magnitude higher than those measured during rock deformation, microfracturing and failure. In this framework, mineral devolatilization reactions can contribute significantly to produce radon emissions spatially heterogeneous and non-stationary in time, resulting in a transient state dictated by temperature gradients and the carrier effects of subsurface gases. Results from these experiments can be extrapolated to the temporal and spatial scales of magmatic processes, where the ascent of small magma batches from depth causes volatile release due to dehydration phenomena that increase the radon signal from the degassing host rock material

Indoor radon: an overview on a perennial problem

According to the World Health Organization (WHO) radon constitutes the second cause of lung cancer in the general population, the first being smoking. In addition health investigations also show that children are more susceptible than adults to ionizing radiation. In the past, it was accepted that only radon concentrations above 400 Bq/m3 could constitute a health risk, however, recent epidemiological findings demonstrate lung cancer risk from exposure to indoor radon at levels in the order of 100 Bq/m3. Furthermore, lung cancer aggravates based on the accumulated inhaled dose and, according to WHO, there is no lower radon level below which the risk from exposure disappears. Nevertheless, some surveys show that the majority of the public seems to consider the health risks involved in radon exposure as being negligible. To make things worse, only a few countries require the use of protection measures for buildings located in radon affected areas. This paper reviews literature on radon as a source of indoor air contamination. It covers recent legislation, building protecting measures and their cost-effectiveness. It also covers the case of radon emissions from construction and decorative materials