of dosage, the accepted level has been set at three feet above the
ground.
The relationship between the intensity measured at the air-
craft and the three foot intensity is proportional to (over an
altitude range from 200 - 1000 ft.)s
I, * Ip= (See Figure 7)
(1)
I, * radiation intensity in airoraft
I, 2 radiation intensity at ground level
u, = Mnear absorption coefficient of air (2¢74)
X = altitude (ft)
Then
Ip = Ty
(2)
EX
And
¢ -i_
Ee
(3)
where fa = altitude correction factor
from (2) & (3), Ip = f, x I,
(4)
and Log 1, = log f, + log I,
(5)
from (3) f, =L - Etux
(6)
log f, = ux or log f, =X
Because the detector output is designed to provide a logarithmic
response, it is only necessary to add the log fe electrically to ob=
tain log Tee
Also — log f, is directly proportional to altitude
(equation 6) and thus may be derived from a radio altimeter.
It is not possible to maintain an aircraft in level flight
and the changes of # 50 feet which normally occur will create
large changes in the radiation reading,
- 13
<-
Thus it is essential to