Spatial Distribution of Radon and Thoron Concentrations Indoors and their Concentrations in Different Rooms of Buildings

Abstract

The concentrations of radon and thoron were measured in a few old and new types of buildings that had four or six different rooms for a period of 1 year from December 2002 to November 2003 using solid state nuclear track detectors (SSNTDs). The dosimeters containing the detector (LR-115 Type II Film) used in each rooms were fixed 2m above the floor. After an exposure time of 90 days films were etched to reveal tracks. From the track density determined using a spark counter the concentrations of radon and thoron were evaluated. Higher radon and thoron concentrations were observed in older buildings rather than new types and a lecturer hall. This is because types of flooring and ventilation conditions are different for different buildings. Seasonal variation and spatial distribution of these gases from the floor surface and walls were studied and analysed.