(
in the PATAPSCO deck log for 10 March 1954.
In order to estimate the cumulative gamma dose (D) over various time intervals
(t,, to) as expressed by equation (1),
t
(1)
f
D
a: 1
R,
‘
dt
it is first necessary to evaluate the dose rate (R,) as a function of time.
This is usually accomplished by defining a set of “unit reference dose rate"
fallout deposition contours so that subsequent decay corrected dose rates can
be expressed relative to these unit hour (t = H + 1) reference rates, (R,)
according to the equation
(2)
R, == Ry t -1.2 .
‘Actually since the fallout is seldom if ever all down at H+1 hour at any location, and since the R, values must be based on the total cumulative deposition,
Ry is a ficticious quantity defined and used to simplify computations.
In
practice R is calculated from dose rate measurements made at various locations
and times from the relationship.
(3)
This
R,
=
R
is approximately valid, assuming 100% retention of bomb debris deposited
on an infinite plane surface.
All these gamma dose rates are defined for a
point three feet above the surface and are proportionally reduced if some
fraction of the radioactivity is removed by wind, rain or other decontamination,
(2)