EXAMPLE PROBLEM 1.
Given:
R1 = 100 cGyph and n = 0.8
Find:
Rt at H + 7 hours
Answer:
20 cGyph
SOLUTION: Using Figure 6-6, align the hairline with 7-hour tickmark of the 0.8 time scale and equal
values of the left and right reference lines. Mark a point on the index scale where the hairline intersects
it. Then pivot the hairline about this point to the 100 cGyph tickmark on the R1 scale. Read the dose
rate at H + 7 as 20 cGyph at the point of intersection of the hairline with Rt scale.
EXAMPLE PROBLEM 2.
Given:
R1 = 2,000 cGyph, Rt = 45 cGyph, and n = 2.0
Find:
The time when the dose rate will be reduced to 45 cGyph
Answer: H + 6.75
SOLUTION: Using Figure 6-7, align the hairline with 45 cGyph on the Rt scale and 2,000 cGyph on
the R1 scale. At the intersection of the hairline with the index scale, pivot and align equal values on the
left and right reference lines. Read 6.75 hours at the point of intersection of the hairline with the 2.0
time scale.
CM2308
6-12
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