RA14 Application Notes
www.teviso.com Rev. 12.02.2016 Copyright © Teviso Sensor Technologies Ltd 2015
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Radon Detector RA14 Application Notes
Measuring the Radon Concentration
Some level of radon will be found in all homes. Radon mostly enters a home directly from the soil
through the lowest level in the home that is in contact with the ground.
Radon exposure in homes and offices may arise from certain subsurface rock formations, and also
from certain building materials (e.g., some granites). The greatest risk of radon exposure arises in
buildings that are airtight, insufficiently ventilated, and having foundation leaks that allow air from
the soil into basements and dwelling rooms.
Radon concentrations in the same location may differ by a factor of two over a period of 1 hour.
Also, the concentration in one room of a building may be significantly different from the
concentration in an adjoining room.
Because radon concentrations can vary seasonally, it would be best to measure radon over the
longest period of time possible. Ideally, this would be one full year because this allows you to
determine the annual average radon concentration in your home.
The average annual radon concentration should not exceed 200 becquerels per cubic meter (200
Bq/m³) in the normal occupancy area.
Data Logger
For analyzing the collected samples the activities of Pb-214 and Bi-214 are of primary interest.
Both Pb-214 and Bi-214 decay via beta decay followed by gamma emission. Electrostatic
collection of the Rn-222 progeny Po-218 is a practical method to get a representative measure for
the concentration of radon in the environment being monitored. Sampling times of at lest 3 hours
are recommended. Consistent results over longer periods of time are available by using software
displaying the detected radiation in a count rate vs. time graph.
Radon concentration monitored over a period of 24 hours in a room in the basement of the building