Dynamic viscosity coefficient mPa s 0. Selected physical and chemical properties of radon. The decay of Radon in air gas phase results in the spread of radioactive aerosols and their deposits mainly in case of Rn may become hazardous long-lived deposits. Radiotoxicity of radon is thus an important factor, since it may be released from natural sources e.
This article has been cited by other articles in PMC. Abstract This study examined correlations between radon, thoron and thoron progeny concentrations based on surveys conducted in several different countries.
Radon and thoron concentrations were measured using passive discriminative radon-thoron detectors. Weak correlations were found between radon and thoron as well as between thoron and thoron progeny. The statistical evaluation showed that attention should be paid to the thoron equilibrium factor for calculation of thoron progeny concentrations based on thoron measurements.
In addition, this evaluation indicated that radon, thoron and thoron progeny were independent parameters, so it would be difficult to estimate the concentration of one from those of the others.
Measurements of natural radiation were carried out in cave dwellings distributed in the Chinese loess plateau. Radon and thoron gas concentrations were measured using a passive integrating radon-thoron discriminative detector. Measurements were conducted in dwellings from August through August A short-term measurement was. Abstract A simple, discriminative measurement technique for radon and thoron concentrations is discussed. In this technique, a single scintillation cell is used for both radon and thoron measurements. It consists of two measurements that use the difference of the half life between the two isotopes. Measurement of radon progeny concentration in air by α-particle spectrometric counting during and after air sampling. Journal of Radiation Research , Online S. Tokonami, A. Sorimachi, H. Takahashi, R. Falcomer. () Preliminary results of simultaneous radon and thoron tests in Ottawa. Radiation Protection Dosimetry
In the past, Rn studies were more common than those of Tn, but recent studies in Serbian [ 1 — 3 ], Chinese [ 45 ], Indian [ 6 ] Canadian [ 7 — 9 ], Japanese [ 10 ], Korean [ 1112 ], Hungarian [ 13 ], Slovenian [ 14 ], Irish [ 1516 ] and USA [ 17 ] dwellings have show that Tn can be a significant contributor to the radiation exposure.
The contributions of Rn and Tn and its progeny TnP to radiation exposure are quite different. The decay half life of Rn is 3. Several parameters, such as dwelling type, ventilation rate and construction materials, influence the Rn concentration in dwellings.
Due to its long half life, Rn is usually well-mixed in room air. On the other hand, due to the relatively short half life of Tn Also, Tn can interfere with the detection of Rn in detectors that lack diffusion barrier discrimination and thus allow rapid gas entry into the sensitive volume [ 22 ].
For a rough estimation of lung dose using the equation given by UNSCEAR [ 23 ], several important components are required, such as the equilibrium equivalent concentration EECthe equilibrium factor F and gas concentration C.
Since direct measurements of the concentration of all short-lived Rn and Tn decay products are difficult and limited, the EEC is estimated from considerations of equilibrium or disequilibrium between Rn and Tn and their decay products, and is expressed by the equation: Several groups have reported the Rn equilibrium factor to be within the range 0.
On the other hand, simultaneous long-term measurements of Tn and its progeny have rarely been conducted, and there is a shortage of data on EEC for Tn [ 426 — 32 ].
A previous study carried out by the Chinese Laboratory of Industrial Hygiene and the US National Cancer Institute showed an increased lung cancer risk due to high residential Rn levels.
Other Chinese surveys provided by Tokonami et al. Simultaneous measurements of indoor Rn, Tn and airborne TnP were made in Ireland for the evaluation of long-term exposures in dwellings [ 16 ].
The Korean studies were designed as nationwide surveys for Rn, Tn and TnP to provide annual averages of them and to estimate the effective dose for the general public [ 35 ].
In addition, the problem of evaluation of the Tn equilibrium factor was considered. These detectors were developed and evaluated at NIRS. The working principle for both detectors is the same. A detector consists of two diffusion chambers with different air exchange rates.
The Rn gas in the air diffuses to the LER chamber through a very narrow invisible gap, while Tn diffuses through evenly distributed holes made on the HER chamber wall.
The LLD depends on the concentration of both gases and on the exposure period.
In the first version of the detector Fig. CR chips are covered with an aluminium-vaporized Mylar film of mm air-equivalent thickness. The thickness of the Mylar film allows the detection of only the 8.
The LLD of the modified detector was estimated using the Currie formula [ 43 ] to be 0.measuring radon and thoron separately, such as the RADUET used in the simultaneous radon and thoron surveys in Canada .
If an ATD is designed for radon measurement, but sensitive to thoron, it gives a total concentration. ESTIMATION OFANNUAL EFFECTIVE DOSE DUE TO RADON AND THORON CONCENTRATIONS IN MUD DWELLINGS OF MRIMA HILL, KENYA M.
Chege1,*, (SSNT) detectors were used for simultaneous measurement of radon and thoron. The canister used for the measurement of both radon and thoron was. Schematic diagram of the simultaneous in situ measurement system for radon and thoron exhalation rates from the ground surface22).
Fig. 2. Topography of Minamidaito-jima. ★: measurement point of measurement errors for radon and thoron have been estimated . Measurement of radon progeny concentration in air by α-particle spectrometric counting during and after air sampling.
Journal of Radiation Research , Online S.
Tokonami, A. Sorimachi, H. Takahashi, R. Falcomer. () Preliminary results of simultaneous radon and thoron tests in Ottawa.
Radiation Protection Dosimetry Comparative analysis of radon, thoron and thoron progeny concentration measurements Miroslaw JANIK1, Shinji TOKONAMI2,*, simultaneous long-term measure- a measurement period of 90 days, the detection limits are estimated to be 5 Bq m−3 and 7 Bq m−3.
Variation of Radon and Thoron Levels in Garhwal Homes term measurement of indoor radon/thoron concentrations (). In present investigation, the measurements of A twin dosimeter was used for simultaneous measurements of radon and thoron inside the houses. The work presented in this paper is a part of the national radon survey.