Ronan Engineering X96SI/R, Инструкция по эксплуатации

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Theory of Radiation Gauging
Gamma radiation gauges operate on the principle of absorption and transmission. A source
holder directs the radiation beam through the vessel and its process material onto the surface of
the detector. As the process material raises inside the vessel, the gamma radiation is attenuated
by the process causing the detector signal to decrease. Therefore, an increase in process level
results in a decrease of transmitted radiation.
The detector’s output signal, described as counts, varies inversely to the process level (or
mass). Shown here is a typical response curve for a continuous level application.
Fairly simple conditions exist when only one process density is involved. In that case, the
variation in mass of material can only be caused by a variation in level of the process. In these
cases, we can be assured that a change in the detector counts is a result of a change in the
process level.
When the process level is full (or high) the process material “shields” the detector which pre-
vents radiation from reaching the detector, producing a low output of counts. When the process
level is absent (or low) the detector is exposed to a maximum amount of radiation which pro-
duces a high output of counts. (Figure 1)
Figure 1
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