OFFICIAL USE ONLY
may receive one rad of radiation dose.
This was calculated in the
following manner.
Step 1.
Determine the total mmber of disintegrations in the
lower large intestine necessary to produce 1.0-rad.
From equation (1)
(Number of disintegrations) (0.5) (8.0x1077) =1
150
Number of disintegrations = 3.8 x 102°
Step 2.
Determine the activity at time of intake to pro-
duce 3.8 x 10°“
intestine.
disintegrations within the large
From equation (2)
3-8 x 1020 = (5) (az) (372°?) (37°? - 5570-87
*
A37 = 2-7 x 107 a/nr.
Ao, = 4.5 x 10” d/hr.
Aok ® 34 pe
* If the time of intake is the 2th hour, then the start of
irradiation of the lower large intestine is 24 + 13 = 37% hour.
Graph Two has been used in estimating radiation doses to the lower
large intestine for prolonged periods of ingestion (Table Two).
The fol-
lowing calculations are illustrative for the period of 2th to the 120th
hour (start of intake at the beginning of the @nd day after detonation
for a duration of four days)
Step 1.
Determine the number of microcuries at time of ingestion
to produce 1.0 rad to the lower large intestine.
OFFICIAL USE ONLY
-3-