This application note describes how to simply and quickly quantify Radon exhalation on surfaces using a Radon monitor like RTM 1688-2, RTM 2200, or RTM 2200 Soil Gas from SARAD GmbH and an exhalation bonnet.
The quantifying of Radon exhalation on surfaces is based on observing the increase of Radon activity concentration related to a well-defined gas volume until a steady concentration level is obtained in a certain time.
The Radon flux (or exhalation rate) E [Bq / (m²s)] on a surface is defined as ratio of (Radon-) activity A [Bq] to a Radon exhalating surface area (area F [m²]) and a durance t [s]:
1) E = A / (F * t) [Bq / (m²s)]
Consider an exhalation bonnet with the shape of a rectangular solid or a cylinder and with a covered area F [m²] and height h [m], also with volume V :
2) V = F * h [m³]
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