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H
3.2.4.3.2 Place the УПГД-3Б carriage holder with the device in
the position, where gamma radiation DER from the
=(10.0 0.1) µSv/h. After the device has been exposed to
H
*
(
10
)
0
radiation, wait for 5 s and proceed to take five measurements of
gamma radiation DER with a 10 s interval. Enter the results in the
report. Calculate the average value of gamma radiation DER
H
*
(
) by the formula (3.1). The value of gamma radiation
(
10
)
DER with gamma background DER in УПГД-3Б
calculated as follows:
*
H
(
10
)
where
from the source and gamma background in УПГД-3Б calculated by
the formula (3.1), µSv/h;
H
*
- is an average value of the device's readings during
(
10
)
Ф
gamma background measurement in УПГД-3Б, µSv/h.
3.2.4.3.3 Determine the main relative permissible error of gamma
radiation DER measurement in percentage by the following method.
3.2.4.3.3.1 Calculate the confidence limit of relative random error
of measurement results as follows:
t
where t = 2.78 - a Student's coefficient at the confidence
probability Р = 0.95 and n = 5;
5
H
*
i
1
(
10
)
*
H
(
10
)
H
- is an average value of the device readings
*
(
10
)
S
,
*
(
10
)
i
5
*
H
(
10
)
,
Ф
77
(3.1)
137
Cs source is
H
, µSv/h, is
*
(
10
)
(3.2)
(3.3)
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