Page 49 - bukuneutron

and the source tube is lowered into the tube to the de-
sired depths of measurement as illustrated in Figure
2.7.

Figure 2.7: Illustraion of Moisture meter containing
neutron radioactive sources inserted into the tube at a
desired depth. Adotpted from [?]

An Americium 241/Beryllium source (typically with
a radiation rating of 50 millicurries/m) emits high-energy
neutrons is used in the measurement. This is a slight
different compared with neutron gauge for the level
and interface measurement where fast neutron has been
thermalized before being used on site. Where, in this
case, thermalization is happened in the soil, so high
thermal neutron will be scattered upon collision of fast
neutron with the wet soil as compared with the dry one.

Lowering the source down into the tube well sur-
36