PART B - COMPUTE THE TIME OF STAY
USING THE M28A1 RADIAC CALCULATOR SET
The ABC-M1A1 RADIAC Calculator of the M28A1 Nuclear Calculator Set can be used to determine
the time of stay in a fallout area when the rate of decay is standard (n = 1.2). To determine the time of
stay using the calculator, the time of entry, H + 1 dose rate, and total dose must be known. These values
are determined the same as was discussed in Part A using the nomogram. To determine the time of stay,
you must set the known data on the calculator. The dose rate is located on the outer disc and aligned
with the H + 1 mark on the intermediate disc. Rotate the inner disc until the time of entry value is
aligned with the time of entry mark on the intermediate disc. Locate the total dose value on the outer
disc, and note the relative position of this mark in relationship to the guide band. Follow the guide band
to the same relative position where the guide band meets the inner disc. At this point, read the value on
the inner disc. The time difference between this reading and the time of entry is the time that personnel
can stay in the fallout area. As an example, with the following data follow the procedures as shown in
Figure 4-2. Total dose is 50 cGy, dose rate is 200 cGyph, and time of entry is H +6.5 hours.
4-5
CM2308
Previous Page
