Reviews methods for the measurement of the activity concentrations of radon-222 daughters in air. Describes method which enables activity concentrations as low as 0.05 pc i/l of ra a to be measured with simple readily transportable equipment. The method presented here also measures RaB (214 Pb) and RaC (214Bi) activity concentrations and working levels with improved precision compared with established methods.
Gives general discussion of sources of radon gas and its daughter products. Reviews measurements made of radon concentrations in air. Outlines control strategies for limiting radon in buildings.
A portable background gamma-radiation dosimeter with a high-pressure ionization chamber was designed. The gamma background radiation dose rate and radon concentration in the air of the 97 new flats were measured. The flats were selected in the houses of the experimental settlement in Suzewiec (quarter of Warsaw), of three settlements of Kodz, and of five settlements of the upper silesian industrial area. For the construction of these settlements building materials typical for new constructions in Poland were used, such as products derived from metallurgical wastes like slag or boiler ash.
Reports measurements of concentrations of thorium, potassium, uranium radium, and relative radioactivity of building materials used in the United Kingdom. Gives table of results. Examines in particular calcined gypsum prepared as a by product in the manufacture of superphosphate fertilizers. Discusses the relationship between radium concentration and gamma-ray dose rate
Reports study of emanation of radon from concrete blocks enriched with uranium ore, placed in an airtight enclosure. The radioactivity of air samples was determined using a high resolution silicon diode detector system.
Describes a method for measuring the radon concentration of three litre samples of atmospheric air without pretreatment. Apparatus used consists of a 12 in. photomultiplier with 2ns (ag) phosphor and counting chamber. A measured efficiency of 38% when the phospor is negatively changed, is in good agreement with theory. The ultimate sensitivity is governed by the background which is equivalent to a concentration of 5 x 10|-4 c/l
Reviews literature on radioactivity in construction material. Finds that radioactivity in building materials used in the United States has received very little attention and that except for studies to find construction materials of very low background, there are no reports of radiological surveys of any U.S. building materials used for general construction purposes. Discusses surveys made outside the U.S.A. and summarized the gamma exposure rates found inside buildings (table 2). Gives bibliography of approximately 270 references.
Discusses mechanisms for radon liberation in dwellings. Mentions survey which found radon concentrations exceeding the maximum permissable concentration of 3 x 10^-12 curies in 13 of the 65 dwellings. Gives expressions for number of radon atoms in indoor air at time t and activity due to radon per unit volume. Discusses liberation of radon from walls and from soil and concludes that if the ventilation is poor or if there is a high emanation of radon, the indoor radon concentration may approach the maximum permissable level.
Calculations of the activity concentration of RaA (218 Po) in the air within living rooms and in the outside air were made at 87 dwellings in England and Scotland. From these measurements together with a determination of the ventilation rate existing in the room at the time of the measurements, the rate at which 222 Rn is emanating from room surfaces into room air in pci/l/h can be calculated.
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