Page 47 - bukuneutron

back-scatter neutron gauge technique. Layout of de-
tection mechanism apply in this gauge is given in Fig-
ure 2.6.

Figure 2.6: Principle of neutron gauge for tank floor
scanning technique.

Usually the gap in between the tank floor with foun-
dation is filled up with the water. This is resulting from
the condensation of vapor underneath the storage tank
floor due to temperature variation in the day and night.
The existence of water can cause corrosion to the bot-
tom surface of storage tank floor. Corroded surface
reduces the strength of tank floor. There is crucial to
determine the amount of water left in the gap and it is
can be estimated using neutron back-scattered tech-
nique.

This technique require some calibrations particu-
larly when come to the determination of water thick-
ness. This can be calibrated by using several thick-

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