teken,
Thus, by necessity, the most practical criteria upen which to base «
decision are gamma dose rate readings, which are in turn related to the
amount of fallout.
Dose
The most immediate solution aight be to establish lower pernitted
dose rate levels et leter times after detonation.
Hovever, if a series of
Gose rates are established for increasing times after detonation se that
their relationship follovs t72°*, then the doses delivered in X hours
(before the material is washed off) will be grester for earlier tines
after detonation.
If one were sure of the tine that the fallout saterial
waz to remain in place, then a scale ef dose rates versus time after detonation could be made to yield the same total dose over the X hours.
Since
there is obviously no set time period for duration of contest that would
be valid for all cases, one might assume the worst case where the aaterial
remains in place until its activity has decayed to an insignificant level,
Dose rates could then be approximated, to yield a given infinity‘dove, by:
De 54st
where:
D ® infinity dose
A # dose rate at tine “t",
If the above discussion is accepted, then the remaining question is to
set the infinity dose,
Here, we must be cleer that whereas the measurements
taken by the monitors, and the data upon which action will be decided will
be gamma dose rate readings, the point of principal concern is the beta dose
delivered to the basal layer of the epidermis (essuzed ac 7 milligrams per
square centineter).
The retio of emission of beta to gama is a function of
.
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