after the burst. Any reading that is not recorded 1 hour (H + 1) after a burst is commonly referred to as

an Rt reading. In order to perform radiological calculations and make decisions on the nuclear

battlefield, all readings must be represented using the same reference time. If this is not done, the

radioactive elements will decay and a true representation of the hazard, past and present, cannot be made

because radioactivity is accumulative in the human body.

For instance, a monitor reports a dose rate of 100 cGyph 5 hours after the burst. The decay rate was

determined to be standard decay **(n = 1.2)**. What was the dose rate at monitor A's location at H + 1?

This can be determined mathematically by the use of nomograms, (Figures S-2 through S-39 in the

Supplemental Booklet).

The formula for the mathematical determination of the decay exponent is found by solving the Kaufman

equation for **n**, decay rate of fallout.

Symbols used in the above equation are:

R1 = dose rate (cGyph) measured at time, T1

(a peak dose rate or later)

R2 = dose rate (cGyph) measured at time, T2

(the last dose rate available)

T1 = the time (H + _____ hours after burst) that

dose rate R1 was measured

T2 = the time (H + _____ hours after burst) that

dose rate R2 was measured

In the equation, the time and dose rate of the earlier reading is represented by T1 and R1 and the time

and dose rate of the later reading is represented by T2 and R2.

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