Measurement of environmental gamma radiation in Norwegian houses

Reports results of measurements of the environmental radiation inside Norwegian houses. Three types of measuring equipment were used: a scintillation rate meter specially designed for low intensity measurement, a geiger counter with a rate meter, and an ionisation chamber. The average doserate in air due to environmental radiation was found to be 87 mrad/year insidehouses with outer walls of wood. 115 mrad/year for buildings with outer walls of concrete and 129 mrad/year for buildings with outer walls of brick. The average of all the 2026 measurements inside Norwegian houses is 83 mrad/year for the dose rate due to gamma rays, when 25 mrad/year due to cosmic rays is subtracted.