Measurements Of Radon Activity Concentration Research Articles

In situ and laboratory measurements for radon transport process study

Characteristics of radon transport in porous media were studied through both in situ and lab-scale measurements. In situ measurements of radon activity concentration, together with soil thoron and carbon dioxide efflux, were carried out on Mt. Etna volcano. More detailed information on radon transport mechanisms has been obtained from laboratory measurements. In particular, we report the first results of a systematic study carried out at the University of Catania (Italy) by means of a facility consisting of a large cylindrical stainless steel vessel, homogeneously filled with different materials. Radon concentration vertical profiles were extracted in low-moisture samples for different advective fluxes, temperatures and porosities.

Estimation of radon risk exposure in selected underground workplaces in the Sudetes (southern Poland)

The risk of exposure to increased ionizing radiation from radon was assessed for two groups of people who spend time, either for work (employees serving these visitors, mainly guides) or leisure (members of the public – visitors), in underground tourist facilities: Bear Cave in Kletno, the Gold Mine complex in Złoty Stok and the Underground Educational Tourist Route in the Old Uranium Mine in Kletno. These facilities had been chosen due to their location within the Sudetes, the most radon–prone area in Poland, and because of continuous radon activity concentration measurements conducted there since May 2008 to the end of January 2012. The selected facilities also meet the criteria for a radiation hazard workplace set by Polish law.The annual limit of the effective ionizing radiation dose allowed for employees in Poland, which is 20mSv/year, is exceeded for guides working in all the facilities. Also, according to Polish radiological protection regulations, their working conditions qualify them as exposed workers of category A or B. After a month's work, guides receive the annual effective radiation dose allowed for category B workers (>1mSv/year) and after a few months – an annual effective radiation dose allowed for people employed in category A conditions (>6mSv/year). Members of the public spending no longer than one hour inside each facility are at risk of receiving small effective radiation doses, ranging from 0.001 to 0.2mSv/h.

Indoor radon activity concentration measurements in the great historical museums of University of Naples, Italy.

Indoor radon activity concentrations were measured in seven Museums of University of Naples, very old buildings of great historical value. The measurements were performed using a time-integrated technique based on LR-115 solid-state nuclear track detectors. The annual average concentrations were found to range from 40 up to 1935 Bq m(-3) and in 26 % of measurement sites, the values were higher than 500 Bq m(-3) which is the limit value of Italian legislation for workplace. Moreover, we analysed the seasonal variations of radon concentrations observing the highest average in cold weather than in warm.

Criteria of radon risk of territories and methods for their determination

The paper analyzes the values used in the assessment of radon potential of territories. It was shown that the most reliable criterion in the assessment of radon risk of territories can be the value of radon activity concentration fixed at large depths. The authors proposed a simple method to assess this value and radon flux density from the soil surface, based on the measurement of radon activity concentration in soil gas at two twice differing depths and the diffusion model of transport.

Preliminary results of indoor radon survey in V4 countries.

The measurements of radon activity concentration carried out in residential houses of V4 countries (Hungary, Poland and Slovakia) show that radon levels in these countries considerably exceed the world average. Therefore, the new radon data and statistical analysis are required from these four countries. Each partner chose a region in their own country, where radon concentration in residential buildings was expected to be higher. The results of the survey carried out in the period from March 2012 to May 2012 show that radon concentrations are <200 Bq m(-3) in ∼87% of cases. However, dwellings with radon concentration ∼800 Bq m(-3) were found in Poland and Slovakia. It was also found that the distribution of radon frequency follows that of houses according to the year of their construction.

Indoor radon levels in workplaces of Adapazarı, north-western Turkey

The main objective of this study is to assess the health hazards due to radon gas accumulation and to compare the concentrations in different kinds of workplaces, in the city of Adapazarı, one of the most important industrial cities of Turkey. For this purpose, radon activity concentration measurements were carried out in schools, factories, offices and outdoors using CR-39 solid state nuclear track detectors (SSNTD). Results show that the mean radon activity concentrations (RAC) in schools, offices and factories were found to be 66, 76 and 27 Bq/m3, respectively, with an outdoor concentration of 14 Bq/m3. The average concentrations were found to decrease as follows for different types of industries: automotive > electronic > metal > textile. Because the maximum measured radon concentrations are 151 Bq/m3 in the schools, 173 Bq/m3 in the offices and 52 Bq/m3 in the factories, the limits of ICRP are not exceeded in any of the buildings in the region. In addition, the estimated mean annual effective doses to the people in the workplace, students, office workers and factory workers have been calculated as 0.27, 0.63 and 0.20 mSv/y, respectively for the region.

Recent developments in radon metrology: new aspects in the calibration of radon, thoron and progeny devices

Due to the importance of reliable measurements of radon activity concentration, one of the past developments in metrology was applied to the field of radon, thus meeting two basic needs: (1) the harmonisation of metrology within the scope of the mutual recognition arrangement, an arrangement drawn up by the International Committee of Weights and Measures for the mutual recognition of national standards and of calibrations issued by national metrology institutes and (2) the increased demands of the European Atomic Energy Community (EURATOM) directive, transferred into national radiation protection regulations with regard to natural radioactivity and its quality-assured measurements. This paper gives an overview of typical technical procedures in the radon-measuring technique group of PTB, covering all aspects of reference atmospheres (primary standards) for radon, thoron and their respective progenies.

Results of outdoor radon monitoring in Bratislava and Novaky

Measurements of radon activity concentration (RAC) were made in two localities of Slovakia. The first one is located on the campus of Comenius University in Bratislava, where radon has been monitored since 1991. The second area is situated in the city of Nováky (midwest Slovakia, ∼150 km from Bratislava). The localities have a different orography. RAC was measured continuously by large-volume scintillation chambers. The outdoor air was sampled at a height of 1.5 m above the ground. Time courses of RAC in both localities have a similar character. The correlation coefficients between RAC in Bratislava and Nováky was quite high (R(2) = 0.45). However, RACs in Nováky were found out to be about two times higher (∼12.1 Bq m(-3)) than in Bratislava.

A new active method for continuous radon measurements based on a multiple cell proportional counter

A new active method for continuous airborne radon activity concentration measurements is developed. It is based upon the use of a specially designed radon Multiple Cell Proportional Counter (MCPC). The constructed MCPC prototype is described and its operation principle presented. This gas-flow counter is a pile-up of 20 adjacent multiwire proportional counters. It uses argon–propane (1%) as the main counting gas mixture to which an appropriate fraction of ambient air is admixed. The airborne radon activity concentration is to be continuously measured through a periodic integral counting of the α particles emitted by 222Rn and its short-lived decay products within the sensitive volume. A Monte Carlo simulation program, taking into account the major physical processes that determine directly the detector performances, has been written and used for design optimization purposes. The simulation results show that the admixture of 10% of ambient air seems to be sufficient to continuously assess radon activity concentration levels ranging from about 15 Bq m −3 up to 2.6×10 5 k Bq m −3 for an integral counting time period of 10 min. The expected radon sensitivity is about 1.16 cpm/10 Bq m −3 with a radon counting efficiency of about 180%. The detector α-pulse height spectra obtained by simulation show a very good agreement with those delivered by the constructed MCPC prototype in its minimal configuration.

Detection efficiency improvement of a large volume scintillation cell

A large volume scintillation cell (LVSC) for radon activity concentration measurements has been reported at MARC-IV. The present paper describes improvements in the detection efficiency of the LVSC and results of the radon activity concentration measurements for indoor air that were performed using the improved LVSC. The cell is a cylindrical shape and has two photomultiplier tubes that are attached to a condensing lens on the photocathode so as to provide good light collection. Individual counting efficiencies were determined to be 0.48 for 222Rn, 0.55 for 218Po, and 0.61 for 214Po. The average counting efficiency per alpha-particle from the radon and its short half-life progenies was 0.55. This value is smaller than the original value reported by LUCAS of 0.86. However, the sensitivity is approximately eight times higher than that of the Lucas cell, which has a smaller volume. A background counting rate of 0.015 cps was obtained. The lower limit of detection (LLD) for the measurements was estimated using the average background counts, the detection efficiency and measurement time. The LLD at 80% statistics confidence limits was less than 10 Bq/m3 when counted within two hours.