Use of the decay nomogram is shown in the following example problems.

possible when joining values with the hairline. Be sure the hairline intersects the vertical line and the

interpolated value, tickmark, as closely as possible. The following problems are concerned with

technique only and do not consider the impact that these high dose rates might have on operations in the

contaminated area.

EXAMPLE PROBLEM 1. Given: Rt = 150cGyph at H + 3 hours

Find:

R1

Answer: 190 cGyph

Solution: Since the soil type (composition) is not known, calculations will be performed on the Soil

Type II (index) Scale. Align the hairline with the 3 hour tickmark on the Soil Type II (index) Scale and

the 150 cGyph point on the Rt scale. Read the dose rate as 190 cGyph at the point of intersection with

the R1 scale (Figure 6-13).