An account is given of the behaviour of thoron and its progeny in the indoor environment. Emphasis is placed on the spatial distribution of these radionuclides in room air and on their interactions with indoor aerosols. How these aspects of thoron and progeny behaviour give rise to special problems for measuring them and assessing their radiological impact are described. Descriptions and compar...

Radon progeny concentration is measured with a total alpha counting system in 185 dwellings in the town of Thessaloniki. The Equilibrium Equivalent radon Concentration (EEC Rn) follows a lognormal distribution with an arithmetic and geometric mean value of 28 Bq/m and 16 Bq/m respectively. Simultaneous in situ alpha and gamma spectroscopy measurements were performed in 60 schools of Thessalonik...

background: radon, thoron and their progenies are the most important contributions to human exposure from natural sources. radon exists in soil gas, building materials, indoor atmosphere etc. among all the natural sources of radiation dose to human beings, inhalation of radon contributes a lot. the work presented here emphasizes the long term measurements of radon, thoron and their progeny conc...

Results of the measurement of indoor radon and thoron carried out in and around Srirampura, Bangalore, India using passive detector technique is presented. Measurements were carried out using twin cup radon-thoron dosimeter using small strips of 12 micron thick LR-115 Type II nuclear track detectors. Measurements were carried out in 60 dwellings for a period of one year on a quarterly time inte...

The mainly sources for indoor radon concentrations in all types of houses are the soil radon flux under the building (about 80%) and the radon exhalation from building materials (about20%). Our paper presents two methods for simultaneous measurement of this exhalation from soil and building materials: (1) -charcoal adsorption, respectively (2)-Lucas cell method. The both methods are applicable ...

Electret ion chambers (EICs), commercially available under brand name E-PERM(®), are widely used for measuring indoor and outdoor (222)Rn concentrations in air. These are designed to respond only to (222)Rn and not to (220)Rn by restricting diffusional entry area. Such radon EIC (R EIC) monitors are modified by increasing the entry area to allow (220)Rn, in addition to (222)Rn. Such modified un...

This study examined correlations between radon, thoron and thoron progeny concentrations based on surveys conducted in several different countries. For this purpose, passive detectors developed or modified by the National Institute of Radiological Sciences (NIRS) were used. Radon and thoron concentrations were measured using passive discriminative radon-thoron detectors. Thoron progeny measurem...

In most countries, radon is the dominant contributor among natural radiation sources to the radiation exposure dose of the general population. Numerous case-control studies of residential radon and lung cancer have been conducted using passive radon (Rn-222) detectors. These studies showed that radon may increase lung cancer risk, but most of them did not show a significant risk. Recently it wa...

Recently there has been an increased interest in the measurement of airborne ""Rn (thoron). Such measurements are particularly targeted in areas rich in thorium, and in facilities processing thorium compounds and associated radioactive wastes. Standard electret ion chambers @-PERMSR)* designed for making indoor and outdoor "^Rn (radon) measurement have very little response to "¡R (thoron). How...

Radon-222 (also known as radon) is a relatively long-lived isotope of radon and originates from uranium present in the earth's crust. Radon-220 (also known as thoron) is a short-lived isotope of radon and originates from thorium present in the earth's crust. Fundamental properties and health hazards of these gases are compared. On the average, the thoron contribution to the total dose to the lu...