the groups of equations (1) and (2) allow determination of the radon concensration
from the alpha activity of the filter by means of a computer.
Ve
EXPERIMENTAL RESULTS
We present a certain number of radon profiles obtained during several sets of
measurements.
A meteorological study made with the help of daily measuremerts of
the Weather Bureau plus measurements on board the aircraft (humidity, wind and
temperature gradient) allow interpretation of the results.
A.
Horizontal Flight
On May 9, 1966 we made a horizontal flight at 500 meters altitude between
Mont-de-Marsan and Toulouse (150 km over a region cut with valleys and of the
same geologic origin).
The south of France is normally in a flow from the north=-
west, a cold circulation at high altitude maintains a strong unstable activity
above France.
The region surveyed was situated at the edge of the disturbance.
There was partial cloud cover of low cumulus.
Curves 1 and 2 of Figure 3 show the variations in filter activity during the
trip out and the return.
Curve 3 shows the alpha activity of the filter for the
case where the radon and daughter concentrations remair constant during sampiing.
The three curves are identical indicating a constant radon concentration during
a flight.
There were no significant variations due to uneven emanation from the
soil.
On June 6, 1966 this same region was in a flow from west, south-west.
Figure 4 shows the concentration profile at the beginning of afternoon at
around 70 km from the coast.
At 1500 meters the rapid decrease of radon concen-
tration indicated a non-uniformity of emanation from the source plane.
emanation above the ocean is negligible.
The
The air takes up radon passing across
Fs TREE GS SEPeTSO eter petey
Influence of an Emanation Discontinuity
+
Be