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...

A thoron experimental house was constructed in a laboratory room of Helmholtz Zentrum München to perform exposure studies of thoron and its decay products under controlled conditions. The single room house (7.1 m(3)) was built from unfired clay stones and clay plaster. For the plaster of the inner side, the clay was mixed with granite powder enriched with (232)Th. The thoron inventory increased...

A rapid method for directly determining the exhalation rate of thoron from material surfaces was studied. Thoron accumulated with the accumulation chamber is detected with the scintillation cell. The alpha counting efficiency of the scintillation cell was estimated by the Monte Carlo calculation. Measurements were carried out in a sandy loam and different building materials. The results show th...

The HMGU thoron experimental house: a new tool for exposure assessment Doses in human organs due to alpha, beta and gamma radiations emitted by thoron progeny in the lung A theoretical study on accurate measurements of thoron with airflow-through scintillation cell method RADIATION PROTECTION DOSIMETRY OCT 2010 141 4 Sp. Iss. SI 448 451 Ishimori, Y Time-integrated monitoring of thoron progeny c...

The annual exposure to indoor radon, thoron and their progeny imparts a major contribution to inhalation doses received by the public. In this study, we report results of time integrated passive measurements of indoor radon, thoron and their progeny concentrations that were carried out in Garhwal Himalaya with the aim of investigating significant health risk to the dwellers in the region. The m...

Radon and thoron isotopes are responsible for approximately half of the average annual effective dose to humans. Although the half-life of thoron is short, it can potentially enter indoor air from adobe walls. Adobe was a traditional construction material in the Great Hungarian Plain. Its major raw materials are the alluvial sediments of the area. Here, seasonal radon and thoron activity concen...

As it is known, the radon (222Rn) gas and its progenies are considered to be the major contributors to human exposure from natural radiation sources [1]. Several surveys seem to have concluded that the radon in the living environment implies an increased health risk [3, 9, 18]. This is the reason why national authorities and international organizations issues guidelines concerning radon levels ...

In the past, the radon isotope Rn (thoron) was often paid little attention in the context of radiation protection at home. Measurements in buildings on the Central-Chinese Loess Plateau have shown, however, that in dwellings built from unfired earthen material, thoron and its progenies can significantly contribute to the inhalation dose of the dwellers. In Germany, such buildings mainly compris...

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...