A new method for determination of222Rn and220Rn in geothermal steam

The radionuclides²²²Rn and²²⁰Rn are measured by incorporating their daughters²¹⁴Pb and²¹²Pb in a very thin layer of PbS and accumulating the alpha spectrum of their daughter products²¹⁴Po and²¹²Po. The median yield was measured as 88% using a known amount of²¹⁰Pb tracer. A single fumarole and all 23 geothermal wells tested were found to contain²²⁰Rn. As isotopes of Th, Bi, Po and Ra, are also absorbed in the PbS layer, the method can be used for determinations of these in tap-water.     

Background of low-level gamma-ray spectrometer due to the atmospheric 220Rn and 222Rn

In connection with low-level gamma-ray counting of natural samples, background due to 220Rn- and 222Rn-daughters was monitored. The results obtained for 4 months showed that the background gamma-ray from 222Rn-daughters was more variable than that of 220Rn-daughters. An efficient air-conditioning was helpful to keep the background stable. It was practically equivalent to the use of N2-gas. Radiometric data for dust samples filtered from the laboratory air suggested that Rn-daughters tended to be removed by air-conditioning.     

Measurement of the Unattached Fraction of 222Rn Progeny Using Wire Screens

A method for the measurement of the unattached radon progeny based on the electrostatic deposition on wire screens has been implemented and calibrated, using only one sampling pump. The importance of being able to measure the short-lived radon progeny resides in the special radiological significance that the unattached fraction has. It was possible to apply this measurement method to several dwellings of Argentina and then, have an estimated value of the unattached fraction under different aerosol source conditions. The remarkable aspect of this method is its simplicity, not only in the sample collection equipment used, but also in the measurement instruments, as well as the counting protocols that are simple and fast.     

A simple technique for surface labeling of solids with222Rn and its short-lived decay products

A simple radioactive labeling technique is described which is based on a recoil injection of atoms of²²²Rn and its decay products from a²²⁶Ra source into thin surface layers of solids.     

Radiological assessment of 222Rn, 220Rn,EERC, and EETC in residential dwellings of district Palwal,Southern Haryana,India

Journal of Radioanalytical and Nuclear Chemistry - A systematic measurement of radon/thoron concentration by using pin-holes dosimeter and their decay products by deposition based progeny sensors...     

Soil gases (222Rn, 220Rn and total radon) and 214Bi measurements across El Avila fault near Caracas, Venezuela

Summary Radon measurements were performed across two sections of the Avila fault near Caracas, Venezuela. The radon concentrations clearly showed the different tectonic features and lithology at the Tacamahaca and Spanish Trail sites. ²¹⁴Bi (U-cps) measurements also were related to the lithology. The passive radon method employed laboratory-made dosimeters with LR 115, type 2 celulose nitrate films as detectors. They were buried in the ground at 30 cm depth. While, the active radon method was performed with a Pylon radon measurement system with Lucas cells. The soil gas was also sampled at 30 cm depths, but for only one minute, which was sufficient to fill the 150 cm³ Lucas cells completely. The total radon counts were then separated into those corresponding to ²²²Rn (radon) and ²²⁰Rn (thoron) by a simple computer routine. A comparison of the active and passive methods for the Tacamahaca section over a three-month period showed that both methods could locate precisely the active fault trace.     

Determination of 222Rn in Iranian mineral waters using liquid scintillation alpha-spectrometry

Liquid scintillation counting (LSC) method has been used for the measurement of ²²²Rn in mineral water samples under a pilot project for the first surveillance in Iran. Low level background LSC counter Quantulus and pulse-shape analysis method have been employed. The concentration of ²²²Rn found in mineral waters of the studied areas ranges from about 1 to 75 Bq/l. The best lower limit of detection obtained with the applied technique was 0.069 Bq/l for a counting time in the range of 236–296 minutes.     

Preparation and analysis of <Superscript>226</Superscript>Ra-<Superscript>222</Superscript>Rn emanation standards for calibrating passive radon detectors

Summary In order to calibrate vials containing charcoal for measurement of radon, emanation sources of radon were produced in-house using ²²⁶Ra salts. Calibrated emanation standards containing solution of ²²⁶Ra(NO₃)₂ absorbed into inorganic compounds were prepared. The emanation coefficient of ²²²Rn for these standards vary from 0.23-0.25. The emanation sources were found to be suitable for calibrating radon monitors.     

Measurement of 222Rn and 226Ra in municipal supply tap water to evaluate their radiological impacts

ABSTRACT

Radon (²²²Rn) and its parent radionuclide Radium (²²⁶Ra) are classified as carcinogen. Human exposes to radon in water via inhalation and ingestion, although ingestion is the only way for radium to enter the human body. In this research, tap water collected from Bornova distinct was studied to determine the concentration of radon (²²²Rn) and radium (²²⁶Ra) for evaluating their radiological impact. For this reason, the annual effective doses for ingestion and inhalation were estimated. The measurements were performed using a collector chamber method. The mean concentrations of ²²²Rn and ²²⁶Ra were determined as 0.85 and 0.76 Bq/L, respectively. It can be stated that the ²²²Rn and ²²⁶Ra concentrations of tap waters here are lower than the international reference levels. Obtained concentration levels were applied to estimate annual effective dose due to the inhalation and ingestion. The dose values are also found to be lower than the recommended maximum values. On the other hand, it should be considered that consumption of these waters (2 L) and average radon and radium concentrations of water are the significant factors for estimating doses.     

Ground based radon (222Rn) observations in Bucharest, Romania and their application to geophysics

Atmospheric radon concentration was continuously monitored in Bucharest-Magurele area both near the ground at 1 m height as well as at 10 m height. This paper presents the results of radon in air near the ground concentrations obtained during the 1 July 2010 to 1 February 2012 period by use of solid state nuclear track detectors SSNTD CR-39. The mean atmospheric radon concentration near the ground at 1 m height was found to be 360.91 ± 66.49 Bq/m³, which was about more than an order of magnitude lower than average radon concentration in range of 44.92 ± 9.94 Bq/m³ recorded for period 1 August 2011 to 20 December 2011 at 10 m height by AlphaGUARD Radon monitor. The meteorological effects on the variation of atmospheric radon concentration were discussed. The analysis of spatio-temporal variations in time series radon concentration in air near the ground is a useful tool to study geo-dynamical processes associated with seismic activity in active Vrancea zone in Romania. Taking off the variations induced by external variables, such as temperature, barometric pressure, rainfall, and other meteorological parameters, can be assessed radon anomalies due to possible tectonic movements and also can be surveyed radioactivity background in relation with nuclear emergencies.     

Emanation of 222Rn from solid bodies of building materials and its measurement

Summary Measurement of ²²²Rn emanation from building components is now mandatory by European law. This implies formulation in terms of basic parameters and design of a routine control procedure. Both are presented here.     

Measurement of electroosmotic and electrophoretic velocities using pulsed and sinusoidal electric fields

In this work, we explore two methods to simultaneously measure the electroosmotic mobility in microchannels and the electrophoretic mobility of micron‐sized tracer particles. The first method is based on imposing a pulsed electric field, which allows to isolate electrophoresis and electroosmosis at the startup and shutdown of the pulse, respectively. In the second method, a sinusoidal electric field is generated and the mobilities are found by minimizing the difference between the measured velocity of tracer particles and the velocity computed from an analytical expression. Both methods produced consistent results using polydimethylsiloxane microchannels and polystyrene micro‐particles, provided that the temporal resolution of the particle tracking velocimetry technique used to compute the velocity of the tracer particles is fast enough to resolve the diffusion time‐scale based on the characteristic channel length scale. Additionally, we present results with the pulse method for viscoelastic fluids, which show a more complex transient response with significant velocity overshoots and undershoots after the start and the end of the applied electric pulse, respectively.     

222Rn gas diffusion and determination of its adsorption coefficient on activated charcoal

The adsorption coefficient is the fundamental parameter characterizing activated charcoal"s ability to adsorb ²²²Rn. The adsorption coefficient is determined for ²²²Rn activated charcoal detectors. In addition, a diffusion and adsorption model is developed for the transport of ²²²Rn in a porous bed of activated charcoal. These processes can be described by parabolic second order differential equation. The equation is numerically solved using the finite differences method. With this model, the ²²²Rn activity adsorbed in the detector is calculated for diverse situations.     

Average daily and annual courses of222Rn concentration in some natural medium

Simultaneous measurements of the²²²Rn concentration in the outdoor atmosphere of Bratislava and in the soil air over one year period have been made. Daily and seasonal variations of the²²²Rn concentration in both media were found. Some attributes of these variations as well as methods of measurements are presented in this work.     

Determination of isotopic ratios of uranium samples using passive gamma spectroscopy with multiple detectors

Uranium samples of various enrichments have been passively counted on the University of Texas detector gamma–gamma coincidence system. By observing gamma rays emitted from ²³⁵U and its daughters compared to gamma rays emitted by ²³⁸U daughters and comparing the data to standards of known enrichments, a technique has been developed to take a uranium sample of unknown enrichment and passively count it to determine its uranium isotopic concentration. Because the gamma rays from ²³⁵U are generally in the low-energy regime, there is a strong susceptibility to background interferences, especially from the Compton background produced from higher energy gamma rays. Other interferences, such as those from the decay series of uranium also exist for ²³⁵U gamma rays. In this light, we have collected data using list-mode to produce two-dimensional gamma–gamma coincidence spectra, which allows us to gate the low-energy gamma rays from ²³⁵U with gamma rays that are in coincidence. In doing this, much of the low energy interferences are reduced, and one can analyze the ²³⁵U gamma rays with high precision. Because of the high density of uranium, self-shielding has significant effects especially in the low-energy regime. To correct for this attenuation the detector system has been modeled by MCNP and self-shielding factors have been calculated across the energy spectrum. A big advantage to this method is the capability of performing this analysis with small (<1 g) samples in a non-destructive and relatively inexpensive manner. If necessary, this analysis can be performed within 24 h if an urgent nuclear forensics scenario arises.     

CFD-based simulation and experimental verification of 222Rn distribution in a walk-in type calibration chamber

A walk-in type ²²²Rn calibration chamber (~ 22 m³) is established at the Centre for Advanced Research in Environmental Radioactivity (CARER), Mangalore University, India which is being used by research groups working on ²²²Rn in India and other countries as well. In recent times, computational fluid dynamics (CFD) technique is opted as an alternative approach for the prediction of ²²²Rn concentration profile in the closed domain. CFD simulations were carried out to study the transient build-up and spatial behavior of ²²²Rn concentration in the calibration chamber. Measurements were performed using active ²²²Rn measuring devices and results of the CFD predictions and direct measurements were compared. A good agreement was observed between the simulated and experimental results with deviation between the two entities being ~ 3% in the case of transient build up and ~ 8% in the case of spatial distribution of ²²²Rn concentration.

     

Local variations of atmospheric 222Rn and 210Pb concentrations in Badgastein (Austria)

²²²Rn was measured and aerosols for ²¹⁰Pb determination were collected simultaneously outdoors at ground level near the train station of Badgastein (1080 m a.s.l.), and later on also on the nearby Stubnerkogel (2230 m a.s.l.). Radon concentrations at lower altitude were up to 140 Bq/m³, on the mountain the usual background levels were found. In contrary to the differing radon levels, the ²¹⁰Pb activity concentrations were in the same order of magnitude for both locations with values between 0.16 and 0.77 mBq/m³.     

Optimization of time resolution and detection limit for online measurements of 222Rn in water

The online measurements of radon in flowing water with high temporal resolution and a lower limit of detection of some Bq/l is of growing interest in environmental research and earth sciences. Promising new fields of application in hydrogeology are the study of exchange and mixing processes and the monitoring of pumping procedures before and during groundwater sampling. A suitable, simple method has been proposed by Surbeck based on the separation of air and water by a diffusion membrane. Process parameters influencing the temporal resolution as well as the radon detection efficiency have been studied. Considering these results a new instrument has been developed enabling online radon-in-water measurement with time resolution of about one minute.     

Measurement of benzene concentration in urban air using passive sampling

The concentration of benzene in urban air in the Tri-City area of Poland (Gdańsk–Sopot–Gdynia, and Tczew) was assessed using diffusive passive samplers (Radiello). Samples were collected during a four-year monitoring campaign (2007–2010) at selected monitoring stations managed by the Agency of Regional Air Quality Monitoring in the Gdańsk Metropolitan Area (ARMAAG) Foundation. The performance of the passive samplers was investigated in a field study that measured the benzene concentration in urban air. The results obtained by the Radiello samplers were compared with the results obtained using an on-line monitor (Chrompack CP 7001). Statistical analysis of the results obtained by the two different techniques (passive and on-line) was performed by a linear regression method (Student’s t-test). The influence of temperature fluctuations on the uptake rate behavior of the passive samplers was also investigated.     

Evaluation of 222Rn and 226Ra concentrations in cement and limestone of Sheikh Buddin Hill,Pezu, Pakistan using different techniques

Lucky Cement Factory, Pezu is using limestone of Sheikh Buddin Hills as a raw material in cement. Workers of the factory have direct and general public have indirect exposure to radiological hazard due to natural radionuclides present in limestone. To address the radiological hazards, limestone, mixed (limestone+clay) and cement samples were evaluate for concentrations of ²²²Rn and ²²⁶Ra using CR-39, RAD7 and HPGe detectors. Maximum mean values of ²²²Rn using CR-39 and RAD7 detectors were found 1447 ± 198 and 1416 ± 74 Bq.m^?3 in cement samples and minimum were found in 536 ± 122 and 525 ± 45 Bq.m^?3 limestone samples, respectively. Maximum mean value of radon exhalation rate of 12.28 ± 1.68 Bq.m^?2 h^?1 in cement samples was found below the world average value of 57.6 Bq.m^?2 h^?1. Maximum mean values of ²²⁶Ra measured by CR-39 and HPGe detectors were found 24.25 ± 3.35 and 23.6 ± 0.70 Bq.kg^?1 in cement samples and minimum were found in 8.98 ± 2.02 and 9.19 ± 0.40 Bq.kg^?1 limestone samples, respectively. A positive correlations (R² = 0.9714) using CR-39 and RAD7 detectors and (R² = 0.9573) using CR-39 and HPGe detectors were obtained for the concentrations of ²²²Rn and ²²⁶Ra, respectively. Maximum mean value of annual effective dose of 347.78 ± 47.58 µSv.y^?1 in cement samples was found below the world average value of 1100 µSv.y^?1.