A multi-detector continuous monitor for assessment of <Superscript>222</Superscript>Rn in the coastal ocean

Summary Radon-222 is a good natural tracer of groundwater discharge and other physical processes in the coastal ocean. Unfortunately, its usefulness is limited by the time consuming nature of collecting individual samples and traditional analysis schemes. We demonstrate here an automated multi-detector system that can be used in a continuous survey basis to assess radon activities in coastal ocean waters. The system analyses ²²²Rn from a constant stream of water delivered by a submersible pump to an air-water exchanger where radon in the water phase equilibrates with radon in a closed air loop. The air stream is fed to 3 commercial radon-in-air monitors connected in parallel to determine the activity of ²²²Rn. By running the detectors out of phase, we are able to obtain as many as 6 readings per hour with a precision of approximately ±5-15% for typical coastal seawater concentrations.     

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.     

A survey of 222Rn concentrations in dwellings of Turkey

As part of a national program to determine public exposure to natural radiation, indoor air ²²²Rn concentrations were determined in dwellings of Turkey. The ²²²Rn concentrations were measured with time-integrating passive nuclear etched track detectors in 27 provincial centers. The indoor radon concentrations were found to be in the range of 10-380 Bq^.m^-3. This revised version was published online in August 2006 with corrections to the Cover Date.     

Measurements of222Rn migration in soil

The concentration of radon (²²²Rn) was measured in the soil near the ground surface, using CR/39 solid state nuclear track detectors. The measurements were carried out in PVC tubes at 0.25 m intervals up to 1.25 m. The detectors were etched in 7N NaOH solutions at 80°C. The -tracks from radon's decay were counted using a microscope. A microscope-camera-computer system developed for automatic counting was also used. The results provide evidence for the non-diffusive transport of radon in soils. A transport length of (46.9±3.2) cm was estimated for radon transport near ground surface. Also the variation of soil's radon concentration was correlate to humidity and atmospheric pressure.     

Charged particle ratio in222Rn indoor atmosphere

The majority of radon daughter products are positively charged; however, their charge is masked by atmospheric ions created along the path of the accompanying -particles. The resulting positive-to-negative particle ratio P, which is usually higher than unity can change during the mitigation of radon daughters; such a change gives evidence that the mechanism is controlled by electric forces.     

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.     

Comparison of three methods for measuring 222Rn in drinking water

Three techniques were used to measure ²²²Rn in drinking water: the degassing method followed by counting in an ionisation chamber (IC); gamma spectrometry (GS); and liquid scintillation counting (LSC). Environmental samples were measured in the field using the IC, and the same samples were measured in the laboratory using GS and LSC. The results obtained using the three techniques are compared and discussed in the context of the new Euratom Drinking Water Directive (2013/51/Euratom), which sets out general principles for monitoring radioactive substances such as radon.

     

222Rn radioactivity in urban waters of fault zone in China: dose rate and risk assessment

Journal of Radioanalytical and Nuclear Chemistry - The exhalation of radon from waters surrounding active fault zones is at present not well understood. In this work, radon concentrations in urban...     

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...     

226Ra and 222Rn concentrations of spring waters in Balaton Upland of Hungary and the assessment of resulting doses

²²²Rn and ²²⁶Ra concentration of 18 frequently visited and regularly used, consumed spring waters on the Balaton Uplands have been measured by radon emanation method and alpha-spectrometry. ²²²Rn concentration varied between 1.5-55 Bq/l while ²²⁶Ra concentration between -601 mBq/l. The expected dose, between 14.1-119 mSv/y, has been assessed from the value of concentration supposing a daily consumption of 1 liter.     

Proficiency testing for measurement of radon (222Rn) in drinking water

The Finnish Environment Institute in collaboration with the Radiation and nuclear safety authority (STUK) carried out the proficiency test for measurement of radon (²²²Rn) in water. Samples were taken from two drilled wells in November 2007. STUK has supplied the regional laboratories with RADEK MKGB-01 equipment based on gamma spectrometry. Two samples for this PT were taken from two drilled wells. Ground water moves irregularly in the process and cracks of the bedrock which is why each participant received an individual sample. Each participant’s sample was measured also by STUK using liquid scintillation counter (LSC) as the reference method in this proficiency test. In estimating laboratory performance the results that deviated less than ±10% from the value measured by STUK using LSC were regarded satisfactory. In total, 73% of the results in the analysis of the sample R1 and 82% in the analysis of the sample R2 deviated less than 10% from the values measured by STUK. The results reported by the participants were generally smaller than the results measured by STUK. The deviation between each participant’s result and the result measured by STUK with the LSC was ?7.4% (Sample R1) and ?6.2% (Sample R2). Due to the lack of certified reference materials and a reliable proficiency testing data, it is impossible to check the traceability of radon measurements by using the reference method (LSC) at this moment.     

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.     

Measurement of 222Rn and 220Rn decay product deposition velocities using SSNTD based passive detectors

In the present study, the deposition velocities of ²²²Rn/²²⁰Rn decay products were measured experimentally using SSNTD based passive detectors, direct radon progeny sensor (DRPS) and direct thoron progeny sensor (DTPS) and the results were compared with obtained values by Monte-Carlo simulations. In both cases, deposition velocities were found to be log-normally distributed and also the experimentally measured geometric mean (GM) and geometric standard deviation (GSD) of (0.12, 1.85) m h^?1 for radon decay products and (0.07, 1.75) m h^?1 for thoron decay products were found to be in good agreement with the simulated values.     

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.     

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.     

Application of ultra-low level liquid scintillation to the determination of 222Rn in groundwater

A procedure for the determination of ²²²Rn in environmental water samples using liquid scintillation counting (LSC) was applied. The extractive scintillator RADONS^Ò and an ultra-low background 1220 QuantulusÔ were used. A minimum detectable activity of 0.1 Bq·l^?1 in 20 ml was found with low-diffusion polyethylene vials and 200 minute measurement time. Quenching effects and possible interferences due to the existence of other radionuclides in the extraction process were studied. The procedure was controlled by gamma-ray spectrometry of the ²²²Rn daughters. Applications to environmental samples collected from spas, wells, and public springs in Extremadura (Spain) are presented.