Campbell CS725, Инструкция по эксплуатации

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CS725 Snow Water Equivalent Sensor
D-5
D.2 Does most of the gamma detection occur under
the area of the CS725?
Answer:
Yes, the closer the distance, the more influence it has on the overall readings
for a given area. The following table provides some theoretical calculations on
the contribution to total counts versus angle from the center.
TABLE D-4. Contribution to Total Counts versus Angle from the Center
Angle Range Outer
Tadius @ 3M Total Count Contribution
with Collimater Total Count Contribution
Without Collimator
Sum
from 0° Sum from 0°
0-5° (0.26 M) 0.4% 0.4% 0.2% 0.2%
5-10° (0.26 M)
1.55% 2.05% 0.85% 1.05%
10-15° (0.80 M)
3.0% 5.05% 1.55% 2.6%
15-20° (1.09 M)
4.3% 9.35% 2.2% 4.8%
20-25° (1.40 M)
6.0% 15.35% 3.1% 7.9%
30-35° (2.1 M)
9.0% 32.15% 5.05% 17.0%
35-40° (2.52 M)
9.55% 41.7% 6.0% 23.0%
40-45° (3.00 M)
9.55% 51.25% 7.0% 30.0%
45-50° (3.58 M)
9.2% 60.45% 7.9% 37.9%
50-55° (4.28 M)
8.6% 69.05% 8.75% 46.65%
55-60° (5.20 M)
7.9% 76.95% 9.15% 55.8%
60-65° (6.43 M)
6.9% 83.85% 9.6% 65.4%
65-70° (8.24 M)
5.8% 89.65% 9.65% 75.05%
70-75° (11.20 M)
4.5% 94.15% 9.2% 92.4%
75-80° (17.01 M)
3.2% 97.35% 8.15% 92.4%
80-85° (34.3 M)
2.1% 99.45% 6.0% 98.4%
85-90°
.55% 100% 1.6% 100%
The table above shows that 23% of the radiation counts come from sources
beyond the 60° beam angle when a collimator is installed versus 44% when the
collimator is removed.